(SST info through 7 Sep 04)
1. Subject: SST parts list/schematic error: output low-pass filter
Date: Wed, 30 Apr 1997 08:54:11 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
There's an error in the SST schematic and parts list. For the 40 meter
SST, L2 and L3 should have 18 turns, or approx. 1.3 microhenries. These
are the same values used in the 40A and Sierra. (Thanks to Bob Parks,
K6AEC, for catching this.)
Also, the crystal filter circuit has been improved since I wrote the
article, and now has L-C impedance transformation at either end. I'll
post the new values for this circuit soon.
Wayne
N6KR
2. Subject: SST article typo: 40m novice-band version VXO range...
Date: Wed, 30 Apr 1997 20:37:41 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
...is about 7.105 to 7.115, not 7.110.
Wayne
N6KR
3. Subject: SST: First production unit completed!
Date: Wed, 14 May 1997 01:49:50 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
I just built the first SST using the revised schematic, production PC board
and cabinet. Looks and works great. Made three test QSOs late this
evening (AZ, TX, WA), all coming back on the first call. I'll try to hook
up with a local tomorrow to get a detailed signal report.
I built the 40-meter version first, but I'll build 30 and 20-meter versions
ASAP. Some preliminary observations on the 40m unit:
* 2.3W out max at 14VDC (this can be increased with one resistor change)
* QSK is fast enough to hear between the dots at >35WPM, with no thumps
* filter bandwidth is about 300Hz at -6dB; peak is near 600Hz
* opposite sideband suppression is >50dB (better measurement later)
* noise floor is extremely low; "sounds like" -140dBm, but I'll
post an actual measurement later (let's put it this way: with the
antenna disconnected, I hear nada!)
* quick test with the KC1 showed no audible receiver interference w/KC1
running
* turns out that the "S-meter"/AGC LED was supposed to be a high-efficiency
red type, not a regular red type. I have to call Bob Dyer first thing
tomorrow to have him change the Mouser order :) Could have been worse....
I'd like to once again thank those of you who ordered early for being
patient. Doing things right takes time!
73,
Wayne
N6KR
4. Subject: SST transceiver theory note: receiver front-end response
Date: Wed, 21 May 1997 08:01:14 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
In the SST article in QRPp, my explanation of how the SST's receiver
front-end filter works left too much to the imagination. Funny how when
you take away some parts, the thing gets more complicated ;) Here's how
it works:
C1 and RFC1 actually form a *series-tuned* circuit, with RFC1 effectively
connected to AC ground by C3 (.01uF). Since the signal is shunted to
ground by C3, the load for the tuned circuit is U1 (NE602), via C2 (5pF).
At the junction of C1/RFC1, the impedance is very high, and C2 provides a
good match to the 1500-ohm input impedance of U1. On transmit, D1 shunts
C1/RFC1 to ground so the series-tuned circuit has no effect.
When the series-tuned circuit is considered together with the low-pass
filter (C34/35/36 and L2/3), you find that the overall response on receive
is much more complex than with the series-tuned circuit alone. It is a
double-humped band-pass response, with the second hump's location dependent
on where the knee in the low-pass filter curve is located. The 5-pole LPF
greatly attenuates the image response, which on 40m is around 15.04 MHz.
Ideally, you want the low-pass filter's knee to be at the same location as
the peak of C1/RFC1. While it is possible to select components for the
low-pas filter that result in an optimal band-pass peak at the operating
frequency, this compromises transmit performance. As an example, consider
C34=C36=1000pF, C35=1500pF, and L2=L3=1100nH. These values work well on
receive, but show a high SWR and excessive ripple on transmit.
Modelling
If you're interested in modelling this circuit, you'll need to also add in
the parasitic capacitance for RFC1 (about 6pF in parallel), as well as
about 4pF for pin 1 of the NE602. On 40 meters, C1's value is around 24 pF
at resonance; RFC1 is 15uH.
For the low-pass filter, I used C34=C36=330pF, C35=820pF, and L2=L3=1.4uH,
which provides a good match from the 2N3553 to a 50-ohm load. This places
the low-pass knee somewhat above 7MHz. You may want to plug in the
low-pass values I mentioned earlier to see the effect of moving the knee
down in frequency.
In order to make the model match reality on receive (with the actual LPF
values), I had to include some capacitance for the zener diode and the
2N3553's collector. I used about 400pF, which may be on the high side, and
eventually I'd like to use a more accurate figure. (If anyone else tries
to model the circuit, please let me know.) In the real SST, the second
hump is near 8.5MHz and about 10dB below the 7MHz peak of the series-tuned
circuit, and the model agrees when I add the extra 400pF at the zener side
of the LPF.
73,
Wayne
N6KR
5. Subject: SST: First QSO on 30m version (WL7VO), plus misc. factoids
Date: Thu, 22 May 1997 01:13:57 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
More SST news (all good) from SST headquarters in Belmont, CA.
I finally had a chance to put the 30m version of the SST on the air.
Conditions were marginal, but I hooked Dick, WL7VO, in Chicken, AK on the
first call. 439 report--not bad for 2W and a vertical. No luck calling
the ZL4 after that....not yet, at least.
Here are a couple of measurements taken on the completed 30-meter version
w/13.8V supply:
Transmit power out, max: 2.7W
Transmit PA efficiency: 77% at 2.O W out
VXO range: 10.105-10.118 w/MV209 varactor
10.097-10.112 w/MVAM108 varactor
Note: High end of VXO range can be moved up to
10.123 with an inductor change
Receiver selectivity: approx. 300Hz at -6dB (AGC off)
Wayne
N6KR
6. Subject: KC1 FREQ. COUNTER NOTE (w/SST): Simple way to improve VFO signal
Date: Tue, 3 Jun 1997 00:22:35 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
The frequency counter section of the KC1 is typically coupled to a strong
VFO or VXO using a small capacitor. However, in the SST, the VXO signal is
both high in frequency and low in amplitude, so I needed a different
method. The technique I'll describe may work in other KC1 installations,
too.
NOTE: These instructions will be included in the SST manual.
Here's the trick:
Instead of connecting the KC1 directly to the VXO, I connected it to the
output of the receive mixer's on-chip buffer (U1, NE602 or NE612, pin 7).
Using this buffer effectively isolates the VXO from the KC1. However, due
to the low VXO amplitude, a large (100pF) coupling cap is needed from U1
pin 7 to the KC1. This large cap causes the KC1 to load down the buffer,
reducing its output voltage. What to do?
An often-used trick with the NE602 to improve oscillator starting is to put
a resistor from pin 7 to ground. What I discovered is that this trick also
stiffens up the buffer, allowing it to tolerate the large coupling cap for
the KC1 without much reduction in signal. (The current drain of the '602
goes up slightly when you do this--less than a milliamp.) There is no
other apparent effect on the NE602's performance.
Besides using the trick above, there are a couple of other steps you'll
need to perform when installing a KC1 in an SST. Here's the complete list:
1. Change R3 on the KC1 from 3.3K to 470 ohms. This greatly improves the
gain of the KC1's on-board VFO amp at high frequencies. (It also adds 3mA
to the KC1's current drain. Can't get something for nothing....)
2. Use a large value for the VFO coupling cap (Cv). 100pF seems to work
fine. Connect the SST to pin 7 of the receive mixer (NE602) through Cv as
shown in the KC1 manual. This is the normal connection point, indicated by
"CTR" on the SST PC board.
3. On the SST, add a resistor from pin 7 of U1 to ground to lower the
impedance of the NE602's on-chip buffer. 15K will do the trick.
4. Other aspects of the KC1 installation in the SST are similar to the
NorCal 40/40A, except that I recommend NOT using the KC1's MUTE output.
Just leave it disconnected. As for the sidetone coupling cap, try .01uF.
The KC1/SST combination installed as described draws 22 to 23mA from 12V
when using headphones. You can shave a couple of mA by substituting a
"micropower" 5V voltage regulator for U2 on the KC1.
73,
Wayne
N6KR
7. Subject: SST #1
Date: Mon, 9 Jun 1997 14:29:01 +0100
From: adams@chuck.dallas.sgi.com (Chuck Adams)
Gang,
Doug sent me email saying that he had good news and he had bad news.
Good news --- he was bringing SST #1 from the production of kits and I
was going to get to build it. Bad news --- the rig was his and he gets
to keep it. :-) followed by :-(
After dinner Doug and I head for the house which is on the other side of
Dallas from the hotel. We get setup and here is the scenario. We have
a complete kit (many thanks to Wilderness Radio and Bob Dyer for doing this)
but the manual was not back from the printers or whatever, so all we have
is a bag of parts and a hand written parts list that Doug did from the only
copy of a list that Bob had. :-) Now, there was a schematic in the Dec
issue of QRPp from NorCal, but that is on the other side of the house,
for the time being. So Doug calls out the part number, say R1, and hands
me the X-ohm resistor and I install it using only the silk screen parts
numbers. It takes us a little of 1.5 hours or so to do this. Time may
vary..... etc. Can't do a review of the manual as I have not seen it.
But you don't need the manual if you have the parts list as witnessed
by the building that took place for this rig.
Parts are good quality and the board is excellent. More detailed review
to follow when I get my 30M version. Only problems encountered and they
are minor, but be warned. Board has two R12 labels. One should be R1.
You won't get this mixed up as one is 1/8W resistor and the other is
a board mounted variable for the RF gain. No biggie. The other is the
PC board mounted slide power switch has the three switch connections and
two legs that need to be soldered to the board. The two legs are slightly
closer together than the holes on the board, so you have to file/scrape
the inside area of the legs to get a neat fit, but experienced builder
and careful builder will lose just a little time in doing this.
There are two trimmer caps to peak receiver input and to tune a LC
bandpass on the transmitter side for the only two adjustments for tuning
up the receiver and the transmitter. I found that the leg separation on
the parts and the board are slightly off and the caps did not sit flat
on the board and the pins did not protrude all the way out the bottom
of the board, but they did solder nicely anyway.
After getting the board assembled and using the toothbrush to remove
the water soluable flux we are now ready for the smoke test. So get
the gel-cel and measure about 12.33V or so and attach the power
cable we are ready to fire the puppy up (it is smaller than the NC40a)
and see how it plays. Power on (the power switch is in the down
position gang) and we hear a hiss in the headphones. Good sign and
I don't hear any frying or smell any thing burning (that comes later).
Get the Tek 191 RF generator and sweep the 20M band (did I tell you this
SST was for 20M?) and hear a signal. Proceed to peak (at this point I
did have to treak down the hallway to the bookcase and get the QRPp
issue with the schematic) the receiver input. Seems to be sensitive
enough.
Now get OHR WM-1 and dummy load and peak output of transmitter. Getting
about 1W out. Now at this point in writing this, let me predict. We
are going to see tons of mods for this rig or add-ons 'cuz there are not
many serious milliWatters in this group. :-) Output test at this time
is at a battery voltage of 12.3V or so and I did not have rig in my
possession long enough to do the detailed K5FO experiments, so later we'll
see and remember this is at 20M where things get a little more difficult
at the RF level.
With Heath freq meter we get a range of 14.045 to 14.059MHz, so not bad
for VXO again on 20M.
During this building and testing I had turned on the Philips PM-3266
scope to look at waveforms and use for peaking. At about the time we
powered up the SST and were peaking stuff and at the time I started
RF output I heard a 'pop' and then the smell of something burning.
I probably lost a heartbeat there somewhere for fear that I had
personally fried something with the screwdriver that I was using to
key the rig (hey, you didn't expect me to go one more time across the
house to get a keyer, paddles, and cables and come back and lose all
that time, did you? I knew you didn't.). Well, it is another prime
example of what I call the 'visitor effect', known to this group as
Murphey's Law. The scope power supply decided to show off for Doug
and went belly up. Not to worry, got a Tec 475 at the HamCom fleamarket
and we'll let you know later in the week or early next week on both
the condition of the insides of the Philips and the Tek 475.
Doug carried the SST around and used it for show-and-tell all over the
place in Arlington and Dallas. :-) Sunday afternoon after the meet
he and I hooked it up to a real antenna and heard VE5, EA1, EA2, and
all up and down the east coast and central US. I picked a clear freq
and called CQ on and off for 30 minutes or so, but noone worked.
Band may have not been in good shape for QRPp as I was doing 900mW at
the time as measured on the WM-1.
Because of the time constraints, I don't have a relative comparison
on RCVR sensitivity to other rigs, so I'll leave the 20M version for
someone else to do. I'll do the 30M and we will see postings on
others experiences. That is partly what this group is all about.
Selectivity seems to be excellent from first impressions.
Doug wasn't about to leave the rig here in TX (you know how the CA vs.
TX thing goes) for any period of time, so at the time of this posting
Doug and JoAnne are on a flight to KS and the SST rig is on its way
to a worldwide adventure over the next year.
Thanks to Doug for giving me a chance to see first hand what we can
expect to see from Wilderness Radio shortly. It was fun kit to build
and the early buy of $69 looks like a good deal and our thanks to
Wayne Burdick for the design and Wilderness Radio for the production
of the kit.
FYI
dit dit
Chuck Adams K5FO CP-60 adams@sgi.com http://reality.sgi.com/adams/
8. Subject: re: SST #1; how to increase power
Date: Tue, 10 Jun 1997 08:13:09 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Folks, Chuck and Doug didn't have the SST manual to look at, but you will.
The manual has a few suggestions for increasing power output, including the
following: reduce the value of R10 from 220 to 150 or even 120 ohms. At
14V, expect about 2W out or more on each band.
I expect Bob to begin shipping the kits in a day or two.
73,
Wayne
N6KR
9. Subject: Re: Extending the SST Frequency Range
Date: Wed, 11 Jun 1997 08:43:05 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi Paul,
To get 40 kHz from the SST you would have to modify the VXO, making it a
VFO instead. The 40-meter version is the only one that this would work on,
since it's the only band where the VFO freq. would be low enough to be
stable (i.e., about 3MHz). I have not attempted this, partly because the
rig is not inteded to be a be-all radio. I'm sure someone will,
eventually.
You'd have to use the varactor tuning, still, but add a large toroid and a
few polystyrene caps, then hand-adjust the toroid until you get to the
desired range. One problem is that the VXO tuning pot is a small one, not
really suitable for tuning a wide range because it is mechanically not as
"clean" as a larger pot. You might be able to find a small 10-turn pot
that fits in the same space, but it won't be easy.
73,
Wayne
>Wayne:
>
>Do you think it will be reasonably possible to extend the frequency range
>of the SST in a similar manner as the Norcal 40? In a previous posting,
>you indicated that limited extended coverage was possible by "bending" a
>second crystal or varactor position and adding a switch.
>
>It would sure be nice to have the 40M version cover 40 or 50 kHz! What do
>you think?
>
>-Paul, W9AC (Ex-N9AZ)
10. Subject: SST on the Air!
Date: Thu, 12 Jun 1997 20:48:17 -0600
From: "Bob Follett"
Gang:
>From Post Office delivery this afternoon to now -- 4.5 hours construction, the
SST is on the Air!
A Quick construction report:
1. I don't think we will be generating as many modification/how do I change
this? messages with this rig as the 40'9er or 38S. Of course there is always
room for the keyer/noiseblanker/frequency readout/tuner/battery and solar
charger additions :-)
2. I found zero errors in the manual.
3. I do have an accurate L/C meter now, and found I needed one T removed from
L2 & L3, the output filters, to get down to specified value.
4. I found the BFO too low in frequency. Wayne mentions using a trimmer
instead of a fixed cap, but I reduced the 33pF to 22pF and got it about equal
to the side tone, where I liked it.
5. The frequency range, using the 108 varacter, is 7.027 to 7.039kHz. I'll
try to raise/expand that tomarrow (You really shouldn't widen the tuning range
-- with the very sharp filter and small tuning knob, the signals pop in and
out as it is. Perhaps Wayne's idea of using both diodes with the s/w is a good
answer, but all I want to do is raise the freq. up to 7.043+
6. I matched the IF crystals and caps to optimize the IF filter design ---
Probably not a good idea. My filter is VERY narrow currently -- guessing, in
the 200-250hz range. I'll either widen with different caps, as Wayne
outlined, or add the VBX which I have on both my Sierra and 40A.
7. The Xmit tuned up immediately to between 2.6 to 2.8 watts (I need to
measure with the scope instead of the WM-1) Very nice! Sidetone is totally
w/o clicks/thumps, and other assorted garbage.
8. Needless to say, with VXO, the rig is very stable. Oh yes, and the AGC
really works well.
Now to add a keyer, 9V supply, swap out the voltage regulator for 9V
operation, etc. Oh yes, and the great paint-the-case debate. (Maybe we could
get a group rate on a mass-anodizing somewhere) I'll have the front and rear
panels scanned in to CorelDraw 5, if anyone needs them in that format. ( can
try .TIF, but generally don't like the conversion to bitmap)
In summary, a great rig! Thanks Wayne and Bob D. I am really looking forward
to taking it backpacking. I think my PL259 plus BNC adapter weighs more than
the rig!
73, Bob
----------------------------------------------------------------
Bob Follett AB7ST, QRP-L # 129, NorCal, ARCI, 10-10, ARS
2861 Estates Dr. VOICE: 801.649.6457
Park City, UT 84060 E-mail: bfollett@ditell.com
11. Subject: SST-40M On the Air
Date: Sat, 14 Jun 1997 03:47:30 -0400 (EDT)
From: Steve Bornstein
G'day Gang,
Completed and tested my SST-40M rig in the wee hours. Rig tunes 7030 to
7039.9 with D4B installed. (Am going to move it up a bit with D4A). Output
power is about 2.5 watts with R10 at 120 ohms (Operating on 13.5v). Power
adjustment pot will adjust power down to nil. Phones audio is sufficient
(using Yaesu phones). Made first contact with WB4KKL in FL at 0620 hrs Z.
A nice haul from Columbus, OH. Sigs varied from initial 459 to 589. FL station
was troubled by static crashes. Painted enclosure by first spraying with zinc
chromate primer followed by black for enclosure halves and grey for front and
rear panels. I will report on further progress, but first impressions are all
positive. Assembly is a snap and manual is excellent. Given it's very small
size and minimal current draw the SST is an ideal take along rig.
73 DE K8IDN STEVE QRP-L 331, ARCI 9059, NORCAL 1717, MIQRP, FISTS 2441,
GQRP 8332, CQRP 1
12. Subject: 20 Meter SST done
Back on 18 June (Daily Digest 761, message #21579), NA5N gave a
detailed technical report on an SST. Among a whole lot of other
things, he mentioned the harmonic suppression seen on a spectrum
analyzer. A while back, WA4KAC (Walt Thomas) let me borrow his
40M SST and check the spectrum at work. I went into it in more
detail, measuring both the second and third harmonics at a variety of
power supply voltages. Here are the details in case anyone is
interested.
Walts rig is pretty much stock, although he did experiment with a
variety of final transistors and ended up with a 2N5262 that I gave
him once, since it provided a bit more power. He mentioned that he
simply wound the toroids as specified in the manual and did not
experiment with compressing and squeezing the turns to get maximum
power. (I wanted to keep the rig longer and remove the coils and caps
in the filter to check the actual values, but he wanted to get the rig
back on the air.)
Equipment setup--HP E3630A variable DC power supply, HP 8590B
spectrum analyzer, .Weinschel 30 dB attenuator (50 watt rating!)
model 24-30-34. The output of the SST was fed through the
attenuator into the spectrum analyzer. Power levels given are in dBm,
or in relation to 1 milliwatt at 50 ohms, and were later converted into
watts. Precise attenuation of the Weinschel was not checked since I
wasn't interested that much in the fundamental power, just the
harmonic suppression, and is presumed to be the nominal 30 dB. The
harmonics are given in negative dBc, or dB below the carrier level.
DC volts Power Power 2nd harmonic Third harmonic
dBm watts -dBc -dBc
13.8 34.4 2.75 37.3 61.3
12.0 33.2 2.09 37.4 61.0
11.0 32.48 1.77 37.44 60.8
10.0 31.59 1.44 37.7 60.0
9.0 30.85 1.21 37.66 59.55
8.0 29.53 0.90 37.77 58.8
7.0 28.27 0.67 37.76 58.0
6.0 27.1 0.51 37.62 57.5
Although the sweep on the analyzer was set wide enough to see
higher harmonics, they were lost in the noise level (which was around
70 dB below the carrier level when the voltage was set to 12.0). No
attempt was made to monitor the signal for quality or otherwise check
performance at the various voltages. The sole purpose of the test was
to observe the harmonic suppression. Interestingly, the second
harmonic remained relatively constant (and easily legal since the FCC
requirement for under 5 watts is 30 dB minimum), while the third
harmonic showed a steady deterioration as voltage went down. I'm
not going to worry about that too much, considering that it still
exceeds the FCC spec by at least 27 dB :-)
73 and Queue Our Pea DE WA8MCQ wa8mcq@abs.net
16. Subject: HELP, my SST howls
Date: Tue, 15 Jul 1997 22:18:21 -0700 (PDT)
From: Kory Hamzeh
I just finished build my 30M SST, it seems to work well, except for the
fact that the receiver starts to howl (go into feedback or oscillation)
when I tune to a strong signal and the volume is turned all the way up.
If I back down on the volume, the howling stops. While it is howling, the
AGC LED is pegged.
This is not a stock build, I've done the following mods:
1. The PA is a MRF237
2. C10 is a 50pf trimmer. What is the correct procedure for determining
the optimum setting for C10?
3. I've done the ABX mod as described in the SST manual.
4. I've installed a 39uh choke between X4 and C10.
5. I've removed one turn from L2.
Other than that, its pretty much stock! :-)
The audio sounds a bit muddy, as compared to my Sierra. Is this normal?
Any help would be greatly appreciated.
Thanks,
Kory
AC6RN
17. Subject: SST-Lucky #13!
Date: Wed, 16 Jul 1997 01:35:29 -0700
From: talljazz@teleport.com (Dan Presley)
Lucky #13 SST 20 is now alive & well (I think!). This is the kit I recieved
as a prize for the "Bumblebee" event (to be held July 27) -I was the 13th
person to sign up for the event through the Adventure Radio Club.
Anyway, I finally finished the radio, and discovered I had intalled IC U5
backwards!I was able to unsolder (next time, sockets!), and even though I
didn't think the chip would withstand being yanked on and slightly chipped
(no pun intended), I was able to reinsert it correctly, and it seems to
work fine.Tuning range is about 14040-058 w/ a 4.7 uH & a 1uH together at
RFC 3 , so I may try to lower it a little more to move the range to above
060. Please listen for me tomorrow (Wed 7/16) at about 1700-1900 UTC around
14055 +-. This rig will be "Bumble-beeing" if all goes well! Thanks again
to Russ & crew for the nice prize, and Russ, I will be contacting you soon
for more detail on our 'secret location' for July 27!
Dan N7CQR
18. Subject: Re: HELP, my SST howls
Date: Wed, 16 Jul 1997 11:07:27 -0700
From: chunt@macromedia.com (Christian Hunt)
I have a similar problem on my 40m SST. If I have the AF gain fully
clockwise and I key, after releasing the key, I get a howl that gradually
fades away. It's loud enough to cause a buzz in my headphones.
Mine is pretty much stock except has a wider filter. This doesn't seem to be the
cause as the howling occurred without it as well.
73, KF6IHU
19. Subject: SST-13 < problem with the audio level of the "sidetone" being
very hot>
Date: Thu, 17 Jul 1997 00:41:10 -0700
From: talljazz@teleport.com (Dan Presley)
Well-first QSO w/ my SST-20-13 was about 10 blocks away! But,it works quite
nicely.A few comments- freq coverage is from 14052-060 with 4.7uH choke for
RFC 3, and 14044-055 with other varactor (I have them selectable with
toggle switch mounted on the front). The mod for tuning linearity (18K
resistor across R4) works very well, and I had no trouble with sharp
tuning. Audio is a bit lower than I prefer, but will leave it as is for
now. I am having a problem with the audio level of the "sidetone" being
very hot, and I have to back off the audio gain before xmit or my ears are
blown off!I realize that it's actually monitoring the output- Anyone else
experience this, or is it unique? Other than that, it recieves quite well,
and I'm anxious for condx on 20 to improve for more qsos!
Dan N7CQR
20. Subject: Re: SST-13 < problem with the audio level of the "sidetone" being
very hot>
Date: Thu, 17 Jul 1997 08:48:28 -0400 (EDT)
From: Chris Cartwright
Dan,
I had the same thing with the 30M version. I opened the IF filter up as
noted in the manual, and it improved the audio, and seemed to reduce the
sidetone a bit. Or maybe I just don't need as much volume, or I got used
to it:) I've see a few posts about the wider filter being nicer to listen
to. I've been having a blast with the little thing, gotta get that KC-1
in there though... and ABX... and RIT... and...
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com --
-- N3XRV QRP WAS 17/9 (w/c) | ccart@erols.com --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? | http://dns.vidtel.com/~ccart --
-- WIMPS Q's=04 30M=04 17M=00 12M=00 STATES=03/00/00 DX=00/00/00 QSL's=00 --
21. Subject: Re: SST-13 < RIT board for the NE4040 for use in SST>
Date: Thu, 17 Jul 1997 09:57:21 -0700 (PDT)
From: Kory Hamzeh
On Thu, 17 Jul 1997, Chris Cartwright wrote:
>
> I had the same thing with the 30M version. I opened the IF filter up as
> noted in the manual, and it improved the audio, and seemed to reduce the
> sidetone a bit. Or maybe I just don't need as much volume, or I got used
> to it:) I've see a few posts about the wider filter being nicer to listen
> to. I've been having a blast with the little thing, gotta get that KC-1
> in there though... and ABX... and RIT... and...
>
Now that you mentioned RIT ....
I ordered the RIT board for the NE4040 from Dan's Small Parts. Once I get
my SST to work properly (no howling!) I will try it and let you guys know
how it works.
Kory
AC6RN
22. Subject: SST Howls < optional DC filter can be installed to prevent the oscillation>
Date: Sat, 19 Jul 1997 02:27:05 EDT
From: tshilhanek@juno.com (Terence J Shilhanek)
My SST 40m version also howled when the audio gain was at maximum.
Looking at the application notes on the LM386 audio chip that is in the
SST, I noticed that there is a comment that if the chip oscillates then an optional DC filter can be installed to prevent the oscillation. The filter is
only a resistor and a by-pass capacitor placed in the lead supplying
power to the chip. I have installed the modification and it seems to
work. The changes can be done on the etched side of the pc board.
1. cut the trace going to pin 6 of U3
2. solder a 100 ohm 1/4 watt resistor from pin 6 of U3 to the contact
next to pin 1 of U3 .
3. solder a .1mf disc cap from pin 6 of U3 to pin 4 of U3
Terry, W0PFR
23. Subject: SST howells < Another thing you can try>
Date: Sat, 19 Jul 1997 14:24:49
From: Steven Weber
Another thing you can try is adding a BFC say 470 ufd to 1000 ufd across
the raw DC power supply leads. Ideally, wire the cap directly across the
power pins of the LM386. A small resistor, say 1 to 10 ohms in series with
the plus supply pin might also help. (with the cap across the audio amp
power pins)
Steve, KD1jv....In the White Mountains of New Hampshire
"Melt Solder"
24. Subject: SST Howls (Update) < Terry (W0OFR) mod worked!>
Date: Mon, 21 Jul 1997 17:48:22 -0700 (PDT)
From: Kory Hamzeh
Thanks to Terence W0OFR, I tried the attached mod and it worked! Also,
another note, while in radio shack picking up the parts for this mod, I
picked up a Nove 43 headphone per someone's recomendation on this list.
Anyway, I tried the headphone before the applied the mod, and the howling
does not happen with the Nova 43 (actually, there is a short burst when the
rig is first turned one, then the howling stops very quickly).
By the way, I highly recommend the Radio Shack Nova 43 headphones. Very
nice and sensitive.
Thanks Terence!
73,
Kory
AC6RN
25. Subject: SST & KC-1
Date: Thu, 24 Jul 1997 09:20:02 -0700
From: talljazz@teleport.com (Dan Presley)
Has anyone had problems installing a KC-1 keyer in the SST? I have a 20M
SST and KC-1 that seems to be misbehaving-won't key consistently from the
paddle, and keeps spitting out the letter "D", and then freezing
up-sometimes it will send a string of dits until I shut the rig down. I
have isolated the paddle lines with ferrite beads & .01 caps in case of
RFI, but this still happens even with reduced power out on the SST. Any
ideas?
Dan N7CQR
26. Subject: Re: SST &KC-1 < Is your ground lead short?>
Date: Thu, 24 Jul 1997 13:14:25 -0700 (PDT)
From: "David D. Meacham"
Dan,
I have no problems with the KC-1 in my 20m SST. Maybe yours is picking
up some RF. Is your ground lead short?
72, Dave, W6EMD
27. Subject: SST 20 - de N3XRV < sounded a bit muddy (400Hz?) so I changed>
Date: Fri, 25 Jul 1997 22:49:32 -0400 (EDT)
From: Chris Cartwright
Just got the 20M SST from K7SZ, sounded a bit muddy (400Hz?) so I changed
C10 from 33pF to 18pF and sounds much more gooder :) Set the output to
one watt, and connected it to a hamstick, stuck in the ground in my front
yard, with three radials, and came within microwatts of working AC4YW in
Florida (abt 800 mi). Even with a bunch of repeats, just couldn't quite
get there. With a straight key no less. Guess I have a chance at the bumble
bees this weekend. I just love this QRP stuff. Sorry, just wanted spout
off a little, I'm going back to sit in the front yard play radio now...
Oh, for the curious: 18ma RX, 185mA TX@12V, 14.035-064 w/MV209
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com --
-- N3XRV QRP WAS 17/9 (w/c) | ccart@erols.com --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? | http://dns.vidtel.com/~ccart --
-- WIMPS Q's=04 30M=04 17M=00 12M=00 STATES=03/00/00 DX=00/00/00 QSL's=00 --
28. Subject: In praise of the SST-20
Date: Wed, 30 Jul 1997 22:35:50 -0700 (PDT)
From: Alan Kaul
I can't say enough nice things about my optimized SST (using Dave-W6EMD's
mods -- and one of my own to increase the VXO tuning 14.046-14.063).
Terrific little rig!!!! Running about 3W output, 15V AC supply.
I've had only 4-contacts -- BUT WITH FOUR DIFFERENT DXCC COUNTRIES!
K0EVZ, SM5AGI, VE4GEC and VK2KM (the SM5 lost me in Euro QRM--but the
rest of the QSO's went to completion).
Three times I answered CQ's, once someone answered mine.
All QSO's between 0420Z and 0530z on 3 different evenings.
My sigs ranged from 589 to 529.
My antenna is an A3 tri-band Yagi at about 40-feet.
Wow!
[] kaul@netcom.com
29. Subject: Re: Noise reduction w/ LM386
Date: Fri, 01 Aug 1997 12:56:18 -0400
From: Randy Hargenrader
Hi Bob,
There are a couple of ways to reduce the high freq hiss
from the LM386.
One is to use a small inductor (2.2mH) in series with the output
device (spkr or headphones).
Another is to play with the feedback circuit by using a "T"
circuit as the feedback circuit.(two resistors and a cap)
You can also peak the audio response by putting an inductor and
capacitor in series to ground from pin 1.
Some circuits I've seen roll off the output with R/C networks.
I have component values for the inductor/cap to pin 1 if youre
interested.
--
73, (Sir)Randy WJ4P
Knightlites QRP-L #296 ARCI #9152 1996 40-9er High Scorer
30. Subject: BuzzNot noise blanker < installed it in my SST on 20M
Date: Mon, 14 Jul 1997 08:55:55 -0600 (MDT)
From: bcutter@teal.csn.net (Bob Cutter)
I cannot say enough about the BuzzNot noise blanker. I installed it in my
SST on 20M and it does an amazing job on my electrical noise.
Another great design from Wayne and available from Wilderness Radio.
72, Bob KI0G
31. Subject: Re: SST ABX Mod
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 07:01:46 -0400
I just went through my notes....
In order to make the ABX mod work on the SST, you'll need to insert a 39
uH choke (molded or toroid) between C10 and X4. Additionally, it will
become necessary to add a 50 pF trimmer at in place of the fixed capacitor at
C10.
Since there's such a tight fit between U2 and X4, you'll need a really
small trimmer cap. I've done the homework for you:
Mouser P/N 24AA024
This is a high quality ceramic trimmer and fits perfectly in place of
C10.
-Paul, W9AC
nnnn
32. Subject: Using TiCK with the SST
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 07:11:35 -0400
I went out on a limb and tried something I hadn't done before.
Since the TiCK is rated between three and five volts, and the SST's
regulated voltage is eight volts, some form of voltage drop is required.
While it's possible to use the TiCK's 78L05 regulator (supplied with the
DIP-style kit), I chose to use two LEDs in series between the SST's eight
volt supply and the TiCK. I'm not sure what, if any additonal current is
spared by not using the additonal regulator, but it was an interesting
experiment nevertheless. If I get a chance, I'll measure current
consumption with both configurations. Until then, I plan on leaving it
this way in mine.
-Paul, W9AC
33. Subject: More TiCK/SST Mods
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 08:48:50 -0400
Like the Like the Wilderness KC1, the Embedded Research TiCK has he
ability to inject sidetone audio into a transceiver. While I generally like to
keep the sidetone off and let the rig provide it's own sidetown when
available, it's still necessary to couple this audio into the rig for
programming puposes. Embedded's Piezo alternative just doesn't cut it
for me.
The TiCK manual states a value of a 1Meg resistor for R3 for use with the
Norcal 40A. The results in a very low sidetone audio level on the SST.
Simply change R3 to 100K to form a more proportional voltage divider. To
my ears, this value provides a sidetone level that's "just right." As an
alternative, one could replace the TiCK's R2/R3 voltage divider with a
100K micro-potentiometer. then you'll have the ability to set the level
anywhere you want it.
-Paul, W9AC
34. Subject: Another SST is Born
From: Craig LaBarge
Date: Sun, 22 Jun 1997 10:04:07 -0400
Gang:
My 30 meter SST kit arrived last week and I finally had some time
yesterday to build it. It took somewhere in the neighborhood of 4 to 5 hours to
build and I encountered absolutely no problems whatsoever. All the parts
were there, instructions were excellent, alignment was trivial, and it
worked like a champ the first time I fired it up. The case was a perfect
fit (and even looks great with the unfinished aluminum).
The only mod I made was to reduce the number of turns on L2 and L3 by
one. When I originally wound them with the specified 14 turns, the inductance
measured at 10MHz seem a tad high. 13 turns brought them in a little
closer to the specified .8 uH. I think mine measured at about .9 or so.
Anyway, I get 2 watts out with a 13.6 volt power supply. Stable as a
rock and the receiver has plenty of audio. I opted to used "D4B" in the VXO
and the tuning range is as specified in the manual.
This morning I fired up the SST and heard a K5 station calling "CQ QRP"
and got him on the first call. He was down in MS and we had a nice chat
despite some very noisy band conditions and the fact that I was pumping 2
watts into my rainspout antenna. He gave the SST a clean signal report.
So, Southeastern PA to MS wasn't a bad first QSO for the little SST.
I finished the SST just in time for some real field testing on an
upcoming vacation to the Outer Banks of NC. I think I'm going to have some fun
with this little rig. After I get back, I'll have to get it painted and
pretty it up a bit.
73, Craig WB3GCK
P.S. The only problem with the rig is that I tend to get hypnotized by
that flashing LED on the front panel!
nnnn
35. Subject: Re: Fw: SST Tuning Range
From: "Bob Follett"
Date: Sun, 22 Jun 1997 10:44:54 -0600
Hi Ken:
Well, its sort of in the manual....
Wayne says you can install both Varacters to cover both their ranges. He
doesn't say how to do it.
Its just a matter of finding a reall small SPDT switch, drilling a hole,
then mounting both Varacters to the switch, hot side of each to the two outer
s/w poles. Then run a wire to the hot side of the PCB board to the s/w
center, and the ground side wire up to both ground sides of the varacters. Its
simple, other than planning where you want the s/w on the panel.
I ended up with mine up high enough to clear the electrolitic caps on the
PC board behind the led.
73, Bob
----------------------------------------------------------------
Bob Follett AB7ST, QRP-L # 129, NorCal, ARCI, 10-10, ARS
2861 Estates Dr. VOICE: 801.649.6457
Park City, UT 84060 E-mail: bfollett@ditell.com
nnnn
36. Subject: Re: SST Tuning Range
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 18:07:36 -0400
Ken:
It's the mod suggested by Wayne in the SST's manual: use a SPDT switch to
switch between the two supplied varactor diodes.
-Paul, W9AC
37. Subject: SST not a toy!/SST mods summarized...
From: pmeier
Date: Sun, 29 Jun 97 11:19:11 -0400
Although the SST is a lot of fun to build and operate, I have come to the
conclusion it is not a toy but a very decent rig. I used it for a few
hours yesterday during field while enjoying the beautiful weather in a
local park here in Michigan.
To preface the next statement let me state that I don't compete seriously
during the June Field Day ( I save that for the Sept. QRP to the Field
:). I go out to a local park and operate for just a few hour to enjoy the
outdoors and have some radio fun. But to my point here... The SST is a
wonderful radio which is very well designed and thought out. I say this
after spending Friday evening building it and then taking it out to
yesterday's FD event.
I made 7 contacts in the first hour on 20 meters with just about 2 watts
into an SLV! This may not sound outstanding but considering the low
power, the ease in which I made contacts in the crowded frey and in with
relatively small 10khz of tuning space I WAS IMPRESSED!
Tuning is smooth as is the keying with no THUMPS! The audio is plenty
loud with a very nice tone. As reported in Chuck's early review the unit
went together easily and quickly. I found only one minor mistake and that
was the value given for the choke RFC5 on the schematic. It was listed as
15uh but is closer to about 34uh. Follow the parts list and use 10 turns
for RFC5. I incorporated the mods posted here on the list and found them
all to be useful. I replaced C10 with a variable trimmer (8-60pf). I
installed the VBX mod but found I kept it about mid way through its
range. I followed Dave Meacham's mods for using a 15K resistor across the
pads of the tuning pot (for tuning linearity) and replaced the 6.8 choke
at RFC3 with a 5.6uh unit to bring the top of the range up from 14058 to
14062. This mod reduced bandwith from 20khz to 10khz however. But then
again, I mostly look for QRPers and this allows plenty of range for "us".
I also added a KC1 keyer which installed easily and worked flawlessly
(just follow Wayne's directions in the SST manual).
All in all this is a great rig that is very small and very easy to build
and for well under a hundred bucks. In my opinion it's not a toy but
another of WAYNE'S WONDERS.
Pete WK8S
38. Subject: W6EMD mods summary
From: "David D. Meacham"
Date: ??
Gang,
Since I posted the tuning mod on June 18, someone commented that 18k was
a better resistor value. I just got around to trying it. It IS better, in
fact, it is optimum, according to my measurements. Higher values don't do
any good, while lower values give poorer linearity. At 18k, with dial
full counter-clockwise I get 14.054, straight up I get 14.059, and full
clockwise I get 14.063. So the first half of the dial covers 5kHz, while the secondhalf covers 4kHz. Not too shabby!
In case you missed the first posting, the resistor goes across two of the
terminals of the tuning pot (from the wiper to the 8V side). I use the
MV-209 varactor, and a 5.6uH choke (Mouser # 43LS566) for RFC3.
Enjoy!
72, Dave, W6EMD
nnnn
39. Subject: LM386
From: lve1@inel.gov (Larry V East)
Date: Fri, 28 Feb 1997 16:57:36 -0700
Paul -- I just read "The LM386 Cookbook" by you in the latest "Low Down".
Lots of good information there, but I was a bit amazed that you failed to
mention the use of a bypass cap on pin 7. A small electrolytic or
tantalum cap of a few uF from pin 7 to ground will isolate the high gain input
stage of the LM386 from power supply noise, hum, transients, etc. Such a bypass
cap is much more effective in this regard than the "brute force" Vcc
filter that you recommend in your note #2.
You aren't the only one to ignore this; most commercial rigs (and kits)
using the LM386 either fail to bypass pin 7 at all or use too small a
value (0.01uF or 0.1uF) to be totally effective. For example, Index labs uses a
value of 0.1uF in their QRP PLUS and increasing the value to 4.7uF
completely eliminates the "thumps" in the audio output produced by Vcc
transients when the transmitter is keyed.
I don't mean to be critical, but I just don't understand why the proper
use of the LM386 "bypass pin" seems to be overlooked by almost everyone (in
"hamdom", at least) using this device! It's even label "bypass" in the
data books (and your Fig. 2 in your "cookbook" as well).
72, Larry W1HUE/7
40. Subject: Re: LM386
From: gsurrency@juno.com (Gary L Surrency)
Date: Fri, 28 Feb 1997 22:39:06 EST
Amen, Larry! The LM386 data sheet shows up to a 50db Power
Supply Rejection Ratio (PSRR) with a 10uf cap from pin 7 to
ground and the gain at 20 with 6V supply and 1 khz operation.
My Ark30 had a squirrley sounding low level noise before I put a
10uf tantalum on pin 7 to ground. It might have been coming from
some of the digital synthesis circuitry and was most noticeable
when using headphones.
One glance at the LM386's internal equivalent schematic shows
why this decoupling cap is so needed. Pin 7 is right on the chip's
bias network.
BTW, on the ARK30, I placed the 10uf tantalum cap on the foil
side of the transceiver board. It just fits between the PCB and
the shield plate.
I have also found on many op amp circuit designs, that the unused
input pin ALWAYS need to be decoupled if it is not grounded or you
will invariably get keying or T/R thumps in the audio chain. Several
radios I have or have looked at omit this decoupling cap on the
resistive divider on the non-inverting input (+ lead). The TAC-1 had
this problem on the op amp following the CMOS bilateral switch chip.
A 0.33 uf monolythic axial cap fixed it completely, and killed the thump.
Bypass that lil sucker!
72,
Gary Surrency AB7MY
S&S TAC-1(40&80m) and ARK30, AT-11 (QRO and QRP)
QRP-L #571 Chandler, AZ (near Phoenix)Grid Square DM43BH
Az ScQRPions
nnnn
41. Subject: Re: SST-20 mods query from AL7FS
Date: Sat, 2 Aug 1997 18:27:49 -0700 (PDT)
From: Alan Kaul
CC:
"David D. Meacham"
Hi Jim ... my mods are simple ... Dave, W6EMD's are a little harder.
Mine involves the VXO --- add a second 18mHz xtal in parallel (solder it
on bottom of board across the first 18mHz rock), then change the VXO
inductance to around 4uH. I have not yet experimented with a high Q
coil, but I think using a toroid with parallel xtals would increase the
tuning range a bit more. My molded choke coil is low Q and from Mouser
(nominal value approx 3.8uH). VXO range is 14047-14063 using the MV 108
diode. I'm not finished yet -- I plan to experiment a little more.
Dave's mods are a little more complex -- his e-mail address is:
ddm@datatamers.com
and you might ask him about them....I don't want to steal his thunder,
he's told me he's writing a piece for the next issue of QRPp.
GL and report back on your results! 73/72 de alan
[] kaul@netcom.com
42. Subject: SST 2 diodes mod.
Date: Wed, 2 Jul 1997 11:29:12 -0600 (MDT)
From: bcutter@teal.csn.net (Bob Cutter)
I just finished my SST(20M) with the two diodes and a SPDT switch. I really
like the bandspread this gives and would encourage anyone to give it a try.
As the bands improve it is going to get crowded around those calling
frequencies and we need to spread out a bit.
72, Bob KI0G
43. Subject: Re: SSTs
Date: Wed, 2 Jul 1997 13:54:55 -0500
From: wmcshan@REX.RE.ouhsc.edu (Mike McShan)
>John,
(snip)
>reciever. Maybe the problem is your headphones. Have you tried a different
>pair? 72, Dave, W6EMD
I have to agree with Dave. Changing headphones can make a big difference.
On my NC38s, the audio is mediocre with a pair of Sony stereo phones.
However, switching to a similar pair from Radio Shack (Nova 43) results in
a dramatic increase in volume (often to the point of uncomfortable).
Mike N5JKY
Edmond, OK
44. Subject: SST Varactor Switching
Date: Thu, 3 Jul 1997 12:32:03 -0800
From: "walter.b.thomas.1@pop300.gsfc.nasa.gov"
For those folks using a switch to change between
the MVAM108 and MV209 diodes in the SST VXO, consider
using a subminiature DPDT switch. Use one pole to
switch the diodes and the other pole to switch the
resistors used to make the "dial" more linear. The
linearizing resistors will be different for the two
diodes. This worked great on my SST40.
Dave W6EMD found 18K to work best for the MV209 on his
20M SST. I used a 3K0 resistor for the MVAM108 on my
SST40. Your mileage may vary, so you may have to
experiment with the resistor values.
73 Walt WA4KAC
45. Subject: SST VXO Problem
Date: Fri, 04 Jul 1997 22:27:52 EDT
From: kk5py@juno.com (dennis l foster)
Hello to all and hope this makes it to the list as it is my first try! I
built my SST the day it arrived and it worked as advertised except for
one problem that I have sort-of solved. I used the D4A diode and found
that at the top of the tuning range the VXO shuts down. I noticed that I
could push RFC-3 away from X6 with what little movement it had, and the
VXO would work again. I can also just touch X6 and it shuts everything
down until I tune to the lower part of the band spread and it starts up
again. I have temporarily solved the problem by moving the RFC-3 to the
bottom on the board. Touching X6 still shuts everything down but it
recovers as soon as I remove finger! Has anyone else had this problem
and what might be the cause and the correct solution? I think using a
lower value choke in place of RFC-3 would be the remedy but not sure! I
just don't like having to move parts around to get things to work right.
Any and all input would be received graciously! Also, has anyone
successfully integrated the Tick Keyer into the circuit so Tick audio is
available at the headphones?
Dennis Foster
KK5PY
46. Subject: Re: SST & TiCK
Date: Sat, 5 Jul 1997 06:51:06 -0400
From: "Paul Christensen"
Dennis:
Here are two reposts of my previous messages:
I went out on a limb and tried something I hadn't done before.
Since the TiCK is rated between three and five volts, and the SST's
regulated voltage is eight volts, some form of voltage drop is required.
While it's possible to use the TiCK's 78L05 regulator (supplied with the
DIP-style kit), I chose to use two LEDs in series between the SST's eight
volt supply and the TiCK. I'm not sure what, if any additonal current is
spared by not using the additonal regulator, but it was an interesting
experiment nevertheless. If I get a chance, I'll measure current
consumption with both configurations. Until then, I plan on leaving it
this way in mine.
-Paul, W9AC
Like the Like the Wilderness KC1, the Embedded Research TiCK has the
ability
to inject sidetone audio into a transceiver. While I generally like to
keep the sidetone off and let the rig provide it's own sidetown when
available, it's still necessary to couple this audio into the rig for
programming puposes. Embedded's Piezo alternative just doesn't cut it for
me.
The TiCK manual states a value of a 1Meg resistor for R3 for use with the
Norcal 40A. The results in a very low sidetone audio level on the SST.
Simply change R3 to 100K to form a more proportional voltage divider. To
my ears, this value provides a sidetone level that's "just right." As an
alternative, one could replace the TiCK's R2/R3 voltage divider with a
100K
micro-potentiometer. then you'll have the ability to set the level
anywhere you want it.
-Paul, W9AC
47. Subject: "Choking" the SST
Date: Tue, 8 Jul 1997 20:49:11 -0700
From: talljazz@teleport.com (Dan Presley)
I couldn't locate (locally) a 5.6uH choke for my 20M SST, to replace the
6.5 choke in the VXO circuit. I did find a 4.7, so was wondering if I can
wind a few turns on it to get it up around 5.6. Anyone have a 'formula', or
suggestions? Also, this is a smaller molded choke than supplied w/ kit-any
problems? Thanks!
Dan N7CQR
48. Subject: Re: SST Tuning Mod revisited
Date: Fri, 11 Jul 1997 02:14:32 -0700 (PDT)
From: Alan Kaul
Hi Gang .... got home from my trip to Northern California to find
my 20M SST waiting (Bob shipped it priority mail -- it beat me back from the
Norcal Meeting!!!!). I know Dave Meacham has made a pretty good linear
tuning mod by soldering an 18k resistor from the tuning pot to the 8V
regulator. I've still got his post. And I read where someone else changed
C10 to 15pf AND R10 to 120 Ohms -- but I don't know if that was on the 20M
version. If anyone has any mods for the 20 Meter SST, I'd love to hear
about them before I plug in the solder iron!!
Pls and tnx and best 73/72 de alan
[] kaul@netcom.com
49. Subject: The HB Sprint and the SST
Date: Fri, 11 Jul 1997 03:44:57 utc
From: k7sz@juno.com (Richard H. Arland)
Gang:
Had the 20 meter SST on the bands this evening for the HB sprint. What
follows are a few observations.
1. The tuning on my SST is 30 kc with the MV-201 and 50 kc with the
MVAV-108. Unfortunately the latter does not offer coverage in the QRP
section of the band, as it stops at 14052.5 khz. Therefore I opted to use
the narrower tuning range offered by the MV-201 varactor.
2. The stock IF BW is way too narrow. I performed the mod as outlined in
the manual and it is still too narrow for my liking. I;ll have to do some
cap substitutions and see what I can come up with.
3. Even with the wider IF BW (after the mod) tuning was still much too
critical. There is no room for a vernier drive so out came the box of
knobs and a spare NC-40A main tuning knob was stuck on the front of my
SST. It looks a little wierd, but it does a much better job of tuning in
stations.
4. This is a Minimalist's radio. Therefore, it is designed to be used
when camping, hiking, ect, NOT in a normal hamshack. The controls are
somewhat crowded and I find that this is not a pleasurable rig to operate
like the Sierra of the NC-40A.
5. Performance is fantastic considering that it has about 1/2 the parts
of a NC-40A and is about 1/3 the size. Wayne Burdick did one hell of a
job designing this rig. Power output with a 13.8 volt DC supply was 2.25
watts. On a 12 volt Gel-Cell power drops off to just under 2 watts.
Receive sensitivity is very good and selectivity (of the stock radio) is
so good, you often tune right past stations unless you tune R-E-A-L
S-L-O-W.
I have not tried this radio into a less-than-optimal antenna, and I
suspect, upon reading the manual, that performance will suffer
drastically if the antenna is not exactly 50 ohms at the operating
frequency. End of the month, I'll be testing this theory on the Flight of
the Bumblebees from Lake Wallenpaupak.
73 rich K7SZ
50. Subject: SST-Internal Batteries
Date: Sun, 13 Jul 97 18:49:47 +0000
From: tgordish@concentric.net
QRP Folk,
Well after starting a never ending thread on Renewal Batterys, I was
discouraged from using them do to the problem with charging them while in
the rig. I opted for little cordless phone batterys available from Radio
Shack. I bought 2 packs of 3 cells and one pack of 4 cells and soldered
them all together. They fit nicely into the SST and give 12v. Total rig
weight with batteries is only 11.5 oz. Then I hooked up to the switch
and made a solder bridge accross the power switch contacts so that I
could charge the batteries while hooked up to external power and the
switch set in the BATT position. Checked it out and seems to be working
fine. Tried a couple of CQ's but no one was out there. Now a couple of
questions:
1. These batteries are rated at 250mah, will this amount of power get me
through a 2 hour Spartan Sprint or do I need to crank the power down a
bit?
2. What would make a good charging voltage for these 10 little ni-cads?
Is it 13.8v like I use with my gel-cell?
Look out you Spartan Sprinters! (I hope I don't regret divulging the
secrets of my set up!) I won't be able to run the August Sprint, but will
be bringing the rig with me while I serve my annual 35 Navy reserve days
at Great Lakes Naval Station.
72 de
Tim & Aretta Gordish
KB9LGJ & N0YDG
Yuma, AZ
51. Subject: "Potential" Super SST
Date: Fri, 22 Aug 1997 16:53:54 -0400 (EDT)
From: Chris Cartwright
Gang,
I now have an SST for every band (except/N), no I don't want to part with
any:) However, I got a 20M unit from Rich, K7SZ and it tunes ~14.002-052
or 14.036-065 depending on the varactor. This seems *abnormally* wide
and I'd like to find out why, and pass it on to other SST owners. (and
expand coverage on my other two) And yes it's very non-linear, the
"bottom" of the dial is *very* crowded.
I have a fair compliment of test equipment but ne
52. Subject: Re: "Potential" Super SST
Date: Fri, 22 Aug 1997 15:17:18 -0700 (PDT)
From: "David D. Meacham"
Chris,
Why not find out what K7SZ did to it? BTW, my 20m SST xtal says:
ECS H
18.00-20
CHINA K5
It gives a range of 14.054-14.063 with the MV209 Varactor and 5.6uH for
RFC3.
72, Dave, W6EMD
53. Subject: Re: SST - working (replace the PA with an MRF 237)
Date: Wed, 27 Aug 1997 16:29:31 -0700 (PDT)
From: Kory Hamzeh
I was able to get 3 watts easily with a 12 volt supply. The replace the PA
with an MRF 237 (e & c are backwards), took one turn of off L2, and used
110 ohms for r10. I haven't checked to see how much about I can put out at
13.8v yet.
Kory
AC6RN
54. Subject: SST for WWV 10.000 Mhz
Date: Sat, 06 Sep 1997 20:39:37 EDT
From: n4so@juno.com (charles k brown)
The SST for 30 meters can be modified to receive WWV
on 10.000 Mhz.
I have a mod file that has some suggestions for
doing this which are by the designer.
The text file is on this computer-- ask for WWV.txt.
from: n4so@juno.com
Ken Brown, N4SO
QTH nr Mobile, AL/ EM50tk
qrp-l #622
n4so@juno.com
55. Subject: Subject: [27051] Re: SST/40 question
Date: Mon, 22 Sep 97 09:12:03 -0400
From: cjl@mail09.mitre.org (Charles J. Ludinsky)
Frank, G3YCC, writes:
> In message <199709172335.TAA47088@nss2.CC.Lehigh.EDU>, Joel Malman
> writes
>
>> 2. The SST seems to drift a bit more than I expected. Did anyone else
>> notice this?
>>
> I am surprised at that. Unless you have extended the tuning range
> greatly, there should be no problem.
> Have fun!
If the power supply is not quite "solid", some frequency drift will occur. For
example, alkaline batteries (e.g., AAs) will drop sufficiently in voltage
during use to cause the output from the internal voltage regulator to change by
some 10s, or even 100s, of millivolts. This is more than enough to cause
annoying drift and chirps.
72 de Chuck, K1CL
56. Subject: Simple Superhet Transceiver SST
Date: Fri, 26 Sep 1997 12:01:02 -0800
http://www.fix.net/~jparker/wilderness/sst.htm
Wilderness Radio
P.O. Box 734
Los Altos, CA 94023-0734
(415) 494-3806
CREDIT CARDS NOT ACCEPTED
The Simple Superhet Transceiver
SST
The SST is an optimized, superhet rig with an extremely low parts count
(only 80 parts, vs. 100 for a
38-special and 120 for a NorCal 40A).
This may be the easiest to build superhet ever, and it comes with a
miniature custom enclosure, less than
half the size of a NorCal 40A.
SST Features:
- 2 watts out (varies w/band and supply voltage), adjustable down to
zero
- fast, clean QSK with transmit monitoring
- 3-pole crystal filter at a low I.F. (about 4 MHz)
- built-in, no-adjustments AGC with received signal indicator LED
- stable VXO coverage of 10 to 20 kHz using varactor tuning (range
varies w/band)
- very low current drain--about 15mA
- stable operation from 10 to 16VDC, or internal 9V lithium battery
- works with the Wilderness KC1 keyer/ counter and BuzzNot noise
blanker.
- both the KC1 and BuzzNot can be installed inside the SST
- all controls, connectors, and parts mount on a single 3.0" x 3.4"
PC board
- 1.5"H x 3.2"W x 3.5"D custom enclosure (supplied unfinished)
RECEIVER:
A superhet with a sharp, three-crystal filter, operating at a low I.F.
(around 4MHz). The receiver uses a
novel AGC circuit employing a single LED as both the detector and signal
indicator. The AF gain control
and headphone jack are on the front panel. The RF gain is rarely used in
the SST, so I put it on the back.
TRANSMITTER:
The Transmitter has *really* fast, exceptionally clean (totally
thump-free) QSK with TX monitoring, as
in the '40A. Power output is around 2 watts on all three bands with a
13.8V supply, and proportionally less
at 12V or 9V. Power out is adjustable down to zero.
Varactor-controlled VXO rather than a VFO with excellent stability.
Frequency coverage (approximate):
40m 7.032 - 7.042
40m/novice 7.105 - 7.115
30m 10.105 - 10.120
20m 14.046 - 14.064
VXO range can be increased by switching in a second varactor. All VXO
and I.F. crystals used are
*standard* frequencies available from Digikey.
The custom enclosure is about 3W x 3.5D x 1.5H", and is supplied
unfinished. Since the box is so small,
we use .050 aluminum to reduce weight. (With a KC1 on the top and an
internal 9V lithium battery, the
SST makes a great TFR.
PRICE AND KIT INFO:
The SST is supplied only as a complete kit -- no partials.
The kit includes a high-quality double-sided and silkscreened PC board;
a custom, unfinished .050
aluminum enclosure with hardware; all controls, connectors, knobs,
rubber feet, etc.; detailed manual;
and all parts for your choice of bands.
The price for each complete SST is $85.
ORDERING INSTRUCTIONS
1. Please enclose $85 per kit ordered.
2. For each kit ordered, you must specify the band: 40m, 40m/novice,
30m, or 20m. (Remember, this is a
VXO-based transceiver, so the rig does not cover the entire CW band.
Approximate coverage is: 40m,
7.032-7.042; 40m/novice: 7.105 - 7.115; 30m, 10.105-10.120; 20m,
14.046-14.064. Other ranges are
possible with small modifications.)
3. California residents must add 7.75% sales tax.
4. Shipping charges are extra: $3 U.S., $5 Canada/Mexico, $15 DX
(other). This is a per-kit shipping
charge.
5. Please make out checks to Wilderness Radio. We'll also need your
name, call, address, phone number,
e-mail address.
6. Send U.S. funds only (checks drawn on US banks, or an international
money order) to:
Wilderness Radio
P.O. Box 734
Los Altos, California 94023-0734, USA
For more information, call Bob at:
(415) 494-3806
CREDIT CARDS NOT ACCEPTED
57. Subject: SST/20 Question
Date: Sun, 5 Oct 97 19:21:53 EDT
From: Joel Malman
Group,
I finished building an SST for 20 meters today. It seems to work fine..
(first QSO: PA0IJM). Problem: every time I power the SST on, and the AF
gain and RF gain happen to be ALL the way up I get this very (*VERY*) loud
blast of noise.
If I power the SST on, at any other AF or RF gain setting, the rig is
fine .. no loud blast.
Anyone have a clue??
thanks,
/joel wa1qvm
58. Subject: SST-40
Date: Mon, 06 Oct 1997 23:21:26 EDT
From: kc4mhm@juno.com (ed miller)
Gang:
Got the new SST-40 on the air this P.M.
Heard AR station calling CQ and he answered me on my first response. He
was QRO so I had good copy on him, he gave me a 599 for my 2 watts. Who
could ask for any more?
Had to change C10 to 22pf to increase side tone to where I like it.
Tunning range is 7.030 to 7.039. Would rather have 7.035 to 7.043, will
work on that later. Hope the fox is below 7.040 tomorrow nite.
See ya'll tomorrow; Tally Ho.
73 de Ed
KC4MHM@juno.com
59. Subject: sst (Oct 1996 Info from Wayne Burdick)
Date: Sun, 20 Oct 1996 21:27:45 -0800
SST Progress Report #2: built-in keyer option (the
"KC0")
L.Svec,W.Burdick (svecbrdk@well.com)
Thu, 17 Oct 1996 23:42:51 -0800
Messages sorted by: [ date ][ thread ][ subject ][ author ]
Next message: Nick Franco: "NHTF and Coming FoxHunt"
Previous message: Nick Franco: "Re: FOX Novice Mortified!"
For those interested in upcoming SST kit:
I thought I'd give you a little more detail on the promised SST keyer
option, as well as a couple of other SST notes. The SST is so compact
that
I had to plan ahead for where the keyer, speed control and paddle jack
will
go.
By the way: I'm doing the KC0 on my own at this point--it isn't clear
whether I or NorCal will supply it. Also, it is intended just for the
SSTs--it is not a new "product." The KC0 name is just a reminder of its
ancestry. More on that in a minute.
Someone mentioned the pending availability of a keyer based on the new
PIC
12XXX series 8-pin SOIC microprocessor. For those who don't know, SOIC
=
small-outline IC = SURFACE MOUNT. Thank you, in advance, for providing
the
world's smallest keyer, and congratulations for being first to announce
a
ham product based on the new PIC 12XXX series.
The SST keyer uses the same chip, except it's the through-hole version
(i.e., it has 8 leads--same form factor as an NE602AN or LM386N). In my
experience SOIC parts are hard to see, much less solder, so I'm glad
someone else is doing the dirty work. In fact, I'll bet Jeff Anderson
(of
40-9er-in-a-9V-battery-can fame) can't wait to get his hands on one! On
the other hand, if consumer electronics conspires to make through-hole
parts go away, noone over 25 will be able to build kits anymore. ;(
KC0 Features
Back to the KC0: I'm porting the KC1 code to it, less the frequency
counter, which isn't needed on the SST since the dial only covers 20 or
30kHz and it will be calibrated by the user. There's also no message
memory, since the PIC 12XXX parts don't have any EEPROM (yet). When
they
do, probably in 1997, the KC0 will get retrofitted with message memory.
The KC0 includes an input pin that lets you choose between two Iambic
keying emulations, just like the KC1: Curtis mode "A" and Super CMOS
mode
"B". The latter is similar to Curtis mode B except the timing is easier
to
use (thanks again to Bob Finch for pointing this out!). Ya know, I
still
think mode B started off as firmware accident, perhaps on a night when
the
lighting was bad and there was a pet Iguana on the keyboard. :) But
then,
I learned on an old 8044 with mode "A", so I may be a distant relative
of
the Iguana. But there it is--mode B if you want it.
The KC0 will come with a VERY small PC board (< 1" square) that has the
micro, 1/8" paddle jack, and the speed control (a small pot, not a
button). This board will plug right into the SST board using only 3
wires,
and it will mount to the rear panel with holes provided. The keyer jack
holds it to the panel and the speed pot's shaft acts like a stop to the
board from spinning around :)
Other SST News
I'm getting closer to nailing down the custom enclosure size, for those
who
want one. It will be 2.5" wide and 4.5" deep, and just about 1.3" tall.
The 9V lithium battery fits inside, and uses 9V battery clips on the PC
board itself--no more floppy 9V battery connector with wires! In fact,
except for the pots and some happy electrons, the SST is a no-moving
parts
radio :)
Note on the SST's audio output: it WILL drive a speaker, unlike the
40-9er, although I'll still recommend headphones for minimum distortion.
73,
Wayne
N6KR
60. Subject: SST 20 mods, thoughts...
Date: Thu, 9 Oct 1997 16:37:22 +0100
From: Frank G3YCC
I must say I am delighted with the SST (20m) rig, but just pondering
some ideas for mods:
1 It could do with a bit more on the Rx side. Wondering whether to
add a dual gate MOSFET preamp or perhaps a balanced 741 audio preamp.
2 VFO thoughts - I obtained a 16mhz xtl and thought that instead
of the VXO, a NE601 (or 612) mixer/osc using the 16mhz and mixing with
that a 2mhz VFO, which should be pretty stable at that low freq. A
simple tuned cct would clean the o/p up and perhaps a small rf amp to
boost the o/p. This could be built in or external. The VXO could be
either left in and switched off if the VFO is used, but would be there
for compactness if required. If the VXO is not needed, it could be
modded as the VFO on 2mhz +/-.
3 The RF gain on the back is never used here, so, I could use that
as a speed control for a built in keyer...
4 The pwr switch on the back also is redundant in my case, so it
could be used to either switch the VXO on/off and activate the VFO
(above).
With the standard varicap mine tunes 14.046 - 14.056 about. Funny thing
is though, with the tuning pot at either end of it's travel, the VXO
stops working, any ideas?
The output is exactly one watt on the d/load-pwr meter.
--
Frank G3YCC GQRP 042
QRP Web Page: http://www.gqrpclub.demon.co.uk
Packet: G3YCC@GB7HUL.#15.GBR.EU
61. Subject: Re: SST 20 VXO range
Date: Fri, 10 Oct 1997 14:30:35 -0400 (EDT)
From: G3TUX@aol.com
Hallo Frank!
I still have not got around to building my SST/20 - but my pal, Hanns DK9NL,
has completed his. He replaced D4 with a BB205B and now tunes from 14041 to
14063. Hope this info is helpful.
I have downloaded the SST mod. file from your web site - many thanks.
Hope to see you at Rochdale. 73 Chris G3TUX
62. Subject: sst 40M audio problems-howl (See Number 68)
Date: Sun, 12 Oct 1997 10:45:22 -0400 (EDT)
From: PULLJIM@aol.com
HELP ! My 40M SST has a howl or some kind of tone on receive. It draws
17.5M.
Parts are placed correctly, and there are no solder bridges.
I have tried several different head phones, all have the same results. The
howl is clearly heard even with the volume turned down. As volume is
increased the howl is louder, and it draws 22M. Anyone have any ideas ?
63. Subject: Re: SST Mods URL
Date: Sun, 19 Oct 1997 17:09:00 -0700 (PDT)
From: "David D. Meacham"
Frank,
The Fall issue of NorCal QRPp has my SST mods article on page 10. (W6EMT
is listed on the cover as the author, by mistake. It should be W6EMD.)
It's not a web site, but it has several mods!
I understand that the mags will be shipped within the next two weeks.
72, Dave, W6EMD
64. Subject: Re: SST: Greatly improved VXO Range (thanks, N6GA!)
Date: Thu, 23 Oct 1997 23:37:35 -0700 (PDT)
From: Alan Kaul
Hi Wayne ... I did the same thing as CAM and have about 18kHz tuning.
Article describing ''super VXO'' written by a JA and posted to this list
about a year ago, but the Japanese version uses a higher Q coil (slug
tuned from about 4uH to 7uH) according tov the post. I still have a copy
of the original if anyone is interested.
There's another version on one of the 7L-amateur websites (also have it
bookmarked somewhere) and he also uses a shunt resistor of about 10K
across the coil.... let me know if anyone wants to see either.
73/72 de alan, w6rcl
65. Subject: SST: Greatly improved VXO Range (thanks, N6GA!)
Date: Thu, 23 Oct 1997 23:01:47 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
Hope this hasn't already been posted--if it has, I missed it.
At Pacificon, Cam Hartford (N6GA) showed me his 20 meter SST with a neat
twist: over twice the usual VXO range! How did he do it? By simply
paralleling a *second* VXO crystal of the same frequency across the first.
Cam said he got the idea from an article, but I didn't catch where or when
it was published. The basic idea is that the second crystal lowers the
circuit Q. Perhaps Cam will fill us in on more details.
In addition to adding the crystal, he had to reduce the size of the series
RF choke to keep the range from being too large (!). At some point that
tiny pot is too small to tune signals in.
I'm hoping to convince some of you SST owners to try this on your own SST.
Since all of the VXO crystals used are standard microprocessor frequencies
available from Digikey, you shouldn't have trouble getting a "sample"
(wink, wink) of one or two crystals from them.
If you try this experiment, please let me know, whether you do it on the
SST or any other rig. Since I'm revising the SST manual for the next run,
I'd like to include as much information as possible about modifications
that increase the rig's performance.
Have fun!
73,
Wayne
66. Subject: SST VXO Range (Thanks W6RCL!)
Date: Sun, 26 Oct 1997 07:30:15 -0800 (PST)
From: camqrp@cyberg8t.com (Cam Hartford)
Gang -
Sorry for being slow on the draw here, but sometimes the digests just pile
up. It was Alan Kaul, W6RCL, who gave me the idea for using the Japanese
wide-Range VXO in the SST.
In stock form, my 20 meter SST tuned about 16 KHz. Alan sent me one of the
postings from QRP-L that he had collected on the subject of the wide range
VXO, so I thought I'd give it a try.
I sent off to Mouser for a couple 18 MHz crystals and several small molded
chokes like the ones used in the SST. I got a variety of small values so I
could use them singly and in series to get small steps from 1 to 10 uH.
At this point I'll leave out lots of gory details about hundreds of
different crystal/inductor combinations except to say that with the two
Mouser crystals in parallel and the original 6.8 uH inductor in the circuit,
the tuning range was about 70 KHz! This was way too much range for a
one-turn pot, and the thing was drifty.
Wilderness was kind enough to send along two different varactors with the
kit, an MVAM108 and an MV209, so we could choose different frequency ranges.
I ended up using both. My rig is now configured like this - 1) A toggle
switch on the front panel to chose between the two varactors; 2) two of the
Mouser crystals in parallel (one in the original X6 board location, the
second one tacked soldered on the bottom of the board parallel to the
first); and 3) the final value of RFC 3 is 4.8 uH.
This configuration gives the following frequency coverage range - Lo
position, 14.026 to 14.058, and Hi position, 14.056 to 14.070. I could have
gone with a little more inductance and covered 14.000 to 14.070, but this is
a bit much for only two turns of the tuning pot. As an example, a 5.6 uH
inductor gave tuning ranges of 13.982 to 14.047 and 14.039 to 14.065,
respectively.
The downside is that it does drift more than a normally configured VXO. I
haven't done extensive drift tests, but a quick check reveals the following:
in the Lo position, which pulls the crystals farther from their design
frequency, it drifts about 200 Hz in the first twenty minutes, but is fairly
stable from then on. The High position, which covers frequencies much nearer
the crystal frequency, shows only about 60 Hz drift from startup.
All of which suggests that the range can be extended quite a bit by using
two parallel crystals. The tradeoffs are increased drift, along with a
greater range to be handled by a one-turn pot. Miniature ten-turn pots, anyone?
72/73,
Cam N6Ga
67. Subject: SST XCVR SURVEY: your input needed for next release
Date: Wed, 19 Nov 1997 09:14:15 -0800
From: "L.Svec,W.Burdick"
Hi gang,
The SST has passed its field-test, and will now become a permanent part of
the Wilderness Radio product line. I'll be making a number of minor
adjustments to the PC board, enclosure, and circuitry, based largely on
comments sent to me by INET and NorCal QRP club members. Thanks again for
your help!
While I think I've got everything nailed, I wanted to get one more round of
input from those of you who modified the SST circuit in some way, either to
fix a problem or to add new features. Even if you have only duplicated
someone else's modification, I'd like to hear from you. Please send your
answers to the questions below directly to me at svecbrdk@well.com. No
need to copy them to QRP-L unless they are relevant to the entire group
(which I imagine has by now heard plenty of SST stories :)
The revised SST will be available after Jan 1, 1998, and the price is $85.
As before, it will be offered for 40, 40/novice, 30, and 20 meters. If
you'd like more SST information or a Wilderness Radio catalog, please call
Bob Dyer, KD6VIO at 650-494-3806, or send him e-mail at:
qrpbob@datatamers.com.
72,
Wayne, N6KR
* * *
1. Did you build any accessories into your SST, such as a
KC1, Buzznot, etc.? If so, please describe any modifications
that were needed, how well it worked, etc.
2. Describe any modifications that you made to the SST's VXO:
3. Which varactor diode did you use?
___MV209 ___MVAM108 ___BOTH
4. What is your VXO frequency range?
(List two ranges if you used both varactor diodes)
5. Describe any modifications that you made to the receiver:
6. Describe any modifications that you made to the transmitter:
7. Please list any other changes that you'd like to see made
to the SST in the future:
68. Subject: SST Coyote Killer -- One Easy Step
Date: Mon, 24 Nov 1997 20:59:36 -0800
From: "L.Svec,W.Burdick"
A long, long time ago (well, about five months) someone on the list
suggested that the cure for the SST's "howl" problem was to put an
electrolytic cap between pin 7 of the LM386 and ground. He was right!
Normally you don't need a cap here if you run the '386 from a regulated
supply, which is why I left it out. But it turns out that the LED-based
AGC circuit I'm using creates enough of a feedback loop that in some cases
it causes trouble. The pin 7 bypass cleans it up.
Other suggested solutions took two or more parts, so this single cap method
was the one I preferred. After all, I'm genetically programmed to try to
keep parts count low :) and there ain't much room left on the SST's PC
board.
I never could duplicate the problem at my QTH, so I enlisted the help of
several SST owners to try this, and the results are in: we're
three-for-three. Even 1uF will do it, but I already use a 2.2uF cap
elsewhere in the rig, so 2.2 it is. Safety margin doesn't hurt.
So, if you still have a coyote in SST's clothing, kill that critter now
with a "2.2" gauge. You can use any cap with a 10V or higher rating. The
smaller ones will actually fit on the bottom of the PCB.
Once again the INET troops have come through--thanks!
72,
waYne
69. Subject: Expanded SST Freq Coverage
Date: Fri, 28 Nov 1997 18:14:05 -0700
From: Steve Galchutt
I just tried strapping another 18 MHz rock accoss the other one in my
20m SST and I couldn't believe my eyes the the counter said 14,004 to
14,057! WOW...that almost 50KHz hmmmm... now if I can just move it up to
above 14,060! Tunning is a little rapid. Maybe a 10 turn pot would
solve this? But my counter just died @#$*&! ....well time for something
else...like XC skiing. We just got about 15" of new white stuff last
night here in Colorado. sush....sush....sush
--
CUL Steve/n0tu . .
Solar powered QRP/CW
Monument, CO..........email:N0TU@webaccess.net
70. Subject: SST problem
Date: Sun, 14 Dec 1997 19:52:20 -0500 (EST)
From: Chris Cartwright
Just wondering what the most common parts for failure are on an SST that
had been hooked up to a 7AH gel cell backwards. I'm asking for a friend,
really, yeah that's it... I... err... He knows the RFC in the final is
burnt open, the zener and final don't look to healthy, but there is also
no RX. The KC1 seem to function, but is confused, and audio from the SST
(from the KC1) is very weak.
I've told him he should put a fuse and diode in the power jack. I'll make
sure he does when *I* "help" him fix it. 72 es tnx
All kidding aside, I did smoke it, and have and unbuilt 40M SST so I have
"spares" of almost everthing. If no one have been through this before
I'll post the casualty list when I get it back together, and it will have
a fuse and diode this time :) I would like to get the list down to
individual parts instead of "shotgunning" it to get it going. I have the
schematic out now... making a list and checking it twice.
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com --
-- N3XRV ARRL-VE QRP WAS 27/10(w/c) | http://dns.vidtel.com/~ccart --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? NJ-QRP #105 LIQRP #???? --
71. Subject: Re: SST problem
Date: Mon, 15 Dec 1997 00:18:41 -0500 (EST)
From: Chris Cartwright I got a nice note from
NA5N recanting how he killed Dougs SST :) He was right on all counts,
Zener, choke and trace fried.
It took five parts, and all of them were "in stock". The 15uH choke in
the final had been vaporized so I rewound the toroid, and measured it
(six turns instead of ten just like last time). The zener in the output
circut seemed to take the brunt of things. It looked OK from the outside,
but it had turned into a 0 ohm resistor. I replaced the final just on
general principle, it ohmed out a little different than the new one and I
had a bunch of 3553's around anyway. The 78L08 "fused" most of the 602's
and the VFO, it shorted its input to ground and was only putting out 1V,
saving all the "expensive" parts.
I had pulled out all the bad parts, put the new 78L08 in, and fired it up
to see if the RX worked, Jackpot! W7 calling CQ, now where the paddles?
Oh yeah, this thing ain't got no finals in it, pooh. Could have been
worse, could have been a JA at 5NN calling :) Put the final, zener, and
coil in, cranked it up 2W out just like before. Now for the KC-1...
The regulator had gone QRT, put the new one in and turned the radio on,
hmm... no frequency readout, bummer, must have killed it really dead.
Then I accidentally leaned on the key, the familiar .---- .---- -. came
out. Cool, I didn't kill it but it still didn't work. Found the trace
that I was using to ground the keyer was toast, patched the trace and all
is well. (Holding the key closed also grounded the KC-1 so that's what
made it run)
Of course by the time I got it back together the band had folded up, guess
I'll have to fire it up tomorrow night, right after I put that fuse in...
Thanks Wayne for a sturdy little rig, I figure even it I had to go out and
get the parts I'd be out less the ten bucks. 72 es cu on 30 at 100mw!
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com --
-- N3XRV ARRL-VE QRP WAS 27/10(w/c) | http://dns.vidtel.com/~ccart --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? NJ-QRP #105 LIQRP #???? --
72. Subject: XMAS SST and winding Toroids.
Date: Mon, 5 Jan 1998 10:48:26 -0500
From: Peter_Simpson@3com.com
Well, not really. I bought it last summer, but
last week, I dug out the box and decided I had
enough uninterrupted time to build it.
Wayne has done a super job with this rig! It went
right together in about three hours. 4 toroids,
but they are easy to wind if you know the toroid
magic and have the secret toroid tool I learned
about by reading QRPp :-)
It came right up! Alignment took about 10 minutes.
All you need is a voltmeter and a power meter or CB
type SWR meter. I still can't believe the rig was
so easy to build and align.
I haven't even painted the case yet, because I was
so eager to get it on the air. Heard the WO3B fox
with it, but was unable to work him.
No, I don't get anything for this "celebrity"
endorsement, but I think I got a super rig for the
price, and I would recommend the SST for a first time
QRP rig builder because it's so easy to get on the air.
Cheers,
Peter, KA1AXY
P.S.: Toroids are easy...if the wire goes through
the center of the toroid, it counts as a turn. Make
the secret toroid tool by bending a paperclip into a
hook and using it to pull a loop of wire through the
center of the toroid, until the free end slips through.
Count one turn each time the tool goes through the toroid.
[now I'll probably get in trouble for spilling the beans :-]
73. Subject: Re: SST Frequency Range Modification
Date: Wed, 21 Jan 1998 23:36:53 -0800 (PST)
From: "David D. Meacham"
Paul,
I tried it and had unsatisfactory results. Others have had good results.
I think it has to do with how well the two xtals are matched. I had only
one to try, and did not compare the two.
72, Dave, W6EMD
74. Subject: SST (Discrepancy on rfc-2 (1mh)
Date: Sat, 31 Jan 1998 20:21:19 -0800
From: dave_epps@juno.com
Is anyone else building a SST?
A little discrepancy. On rfc-2 (1mh) the parts list reads color code of
blk-brn-red. The rfc furnished reads brn-blk-red.
I am assuming that brn-blk-red really is 1mh and the parts list is
wrong.
Am I right?
This is my first project with my new Edsyn 951sx soldering station that
Tech Amer had on sale and my soldering looks better than ever.
dave ab5pc fresno, ca.
75. Subject: Just-built SST and Frequency Range
Date: Tue, 3 Feb 1998 10:47:48 -0800
From: dave_epps@juno.com
Sure like the operation of the rcvr, although it seems to only tune 3 khz
and should tune 10. Has anyone else solved this?
I don't have a counter yet (anyone recommend one?), so I listen to the
vfo in another rcvr and it tunes 11.043 khz to 11.046 khz.
tks dave ab5pc fresno, ca.
76. Subject: just-built sst and Frequency Range answer
Date: Tue, 3 Feb 1998 14:23:29 -0800
From: dave_epps@juno.com
Re my earlier post of 3 khz tuning.
I just changed the varactors. Wayne was kind enough to supply another one
with the kit.
I mounted it on the bottom of the board "easier" and it worked better
than
I expected. It lowered the vfo 10 khz on the bottom and 5 khz on the top
increasing
the tuning range greatly from before.
Am really happy with the little rig. The rcvr is far better than I
expected.
dave ab5pc fresno, ca
77. Subject: SST Mods - xtal filter
Date: Wed, 04 Mar 1998 20:12:08 EST
From: k7sz@juno.com
I was just wondering if there is a source of mods for the SST by
Wilderness Radio? I have a 40 meter version and would really like to
expand the tuning range without resorting to swtiching between two
varactors or adding a 2nd xtal. Has anyone tried ordering an AT cut
xtal from Jan or Bomar and using this in place of the xtal supplied by
Wilderness? If memory serves, the AT cut xtal will provide the maximum
amount of tuning range.
The xtal filter in the receiver is much too narrow for my liking and I
tried replacing C6 & C9 with 68 pf caps and C7 & C8 with 180 pf
caps...this helped but I needed a wider passband. So, I tried a 56 pf for
C6 & 9 and 150 pf for C7 & 8. This is much better. These ratios are all
basically 1:3 so I don't see why 47 pf and 120 pf could not be employed
for those who desired a wider bandwidth.
rich K7SZ
78. Subject: Another SST on 20 meters -- and a few questions...
Date: Sat, 11 Apr 1998 20:07:27 -0500
From: "Fred Ringwald"
After letting it sit on the shelf for way too long, I finally built my
20 m SST this morning. After stuffing the board and mounting the case
front, back, and bottom, I fired it up, tuned for minimum smoke, and
found the initial signs encouraging. When I peaked C1, I heard code,
and wondered if this was going to be one of those rare conditions when
my kit worked correctly the first time, with no need for
troubleshooting!
Well, when I proceeded to the transmitter alignment, all was not so
well, as I had zero watts out.
After the visual inspection, and voltage checks, I found that all DC
voltages for U4 were correct, but that on U5, Pins 1, 5, and 8 read
several volts rather than 0 as specified on the table. U4 had all the
right voltages. The initial indication was to suspect U5. However, a
scope look at Pin 3 of U5 showed no signal at key-down. Tracing back
to U4, Pin 4, I also had virtually no signal at key-down. Checking
the U4 oscillator circuit, U4 Pins 7 & 8 showed a garbled, minor
signal, not a nice sine wave.
I decided to try replacing U4 with an NE602 that I had on hand. Yes,
the plated through holes made it a little difficult, but I used the
old technique of snipping all the IC leads and removing them one by
one, rather than applying so much heat so as to destroy the board.
After power up, I still had no power out as indicated on my OHR QRP
Wattmeter, but the scope showed encouraging signs. I had a sine wave
on U4, Pins 7 & 8, and also on Pin 4. I followed the xmtr alignment
procedure and got about one watt out. Since my bench supply was a
little over 12 volts, and not 13.8, I figured that I was doing okay.
A few minutes later, I responded to K4QIL's CQ from near Myrtle Beach,
SC, and we had a short QSO despite the efforts of QRO QRM.
The lingering question is: Why does U5, Pins 1, 5, and 8, show
appreciable voltage, and not 0 as the assembly manual table suggests
they should??
Also I found that with the MV209 at D4, I got a tuning range of
14.043 - 14.058 MHz, rather than the spec range of 14.046 - 14.064
MHz.
Trying the MVAM108, I got 14.032 - 14.051 MHz, which was a little
wider band coverage, but further away from the 20 Meter QRP calling
frequency.
Does anyone have any advice on how I can use the wider band coverage
of the MVAM108, but get 14.060 near the center of the tuning range??
(Or at least within the range by at least 5 KHz??
Finally, since I likely missed this discussion when I was
significantly distracted and couldn't monitor QRP-L shortly after the
SSTs came out, does anyone have any noteworthy experience regarding
mods to this rig to improve it? I am particularly interested in the
9V battery option, band coverage ideas, and I do plan to install a
KC-1, as it has been awhile (apart from today) since I have operated a
straight key. I guess I need to participate in straight key night
sometime!!
Thanks for the bandwidth, and thanks in advance for any help you might
be able to offer.
73s,
Fred Ringwald, AB0AE
fred@innocent.com
79. Subject: Re: Another SST on 20 meters
Date: Thu, 16 Apr 1998 09:27:13 -0700
From: "L.Svec,W.Burdick"
Hi Fred,
Thanks for the input on the SST. I'm looking at the voltages you mentioned
to see if there's a mistake in the table, and I'll get back to you on this
later.
As for the frequency coverage:
There is more variation than I thought there would be in the VXO crystals I
selected for the SST. I was constrained to use off-the-shelf frequencies
to keep the cost of the kit low, and some people have ended up being just
shy of the 14.060 mark with the 20-meter unit. (It still amazes me that
there are standard microprocessor crystal frequencies available that get us
close to the QRP frequencies on all three bands...)
There are several possible solutions, and I'll leave it to you to choose
which way to go. We may change the kit in the future to make this easier.
1. The simplest (but not the least expensive) thing you can do is order a
custom crystal from ICM, JAN, etc. Specify an HC49-can crystal with a
frequency about 5 kHz above the highest intended frequency of operation.
Custom crystals are on the order of $10, although this varies widely
depending on what lead time you request and how many you order. If the SST
remains a popular kit, we could conceivably use a custom crystal for 20
meters in the future, but only if the volume is high enough to keep the
crystal cost low. (In large quantities, such a crystal might go for $2,
but only with a 3-month lead time!)
2. The basic issue with a VXO is minimizing capacitance across the crystal
to extend the high-frequency end of the range. The MV209 has a fairly high
minimum capacitance--something like 10pF at 8V--so you could try a
different, lower-capacitance varactor here. The MV2104 comes to mind, but
check out the Motorola RF devices catalog (on the web), as well as Zetex
(also on the web). You can also reduce the size of the choke in series
with the crystal: the smaller the choke, the higher the high end of the
range (in general), with a corresponding reduction in tuning range.
3. You can try to put two identical VXO crystals in parallel, one on the
bottom of the board soldered directly to the leads of the one on the top.
If you do this, you can greatly extend the tuning range; in fact it will
tune farther than you want in some cases, necessitating a reduction in the
size of the choke. I haven't tried this on the 20m unit, but it would be
worth expermimenting to see what you get. What you don't want to do is
tune more than about 30kHz. The small pot on the SST is easiest to use
with a 10 to 20kHz range.
4. As I mentioned, reducing capacitance at the high end is everything.
You may want to experiment with a small air-variable capacitor as a
substitute for the varactor tuning, in which case the pot will be replaced
with a panel-mount variable capacitor. Make sure you use one with a really
low minimum capacitance, perhaps 2 to 3 pF.
I hope one of these techniques does the trick! Let us know your results--
73,
Wayne
N6KR
80. Subject: SST AF Gain and Monitor Tone Problem identified
Date: Tue, 12 May 1998 23:05:19 -0600
From: "mike newbold"
i just assembled a wilderness SST rev. B. The kit went together great and
is working, but in the digital portion of twenty mtr. i.e. 14.065 to
14.070. should be 14.050 to 14.060. Also I have to crank the AF almost all
the way to hear anything. And by then the monitor tone is way to loud. any
one have any suggestions..... please. Catch a
wave 72 73, Mike K YO newbold@cmn.net
81. Subject: Frequency Range Adjustment Parts change
Date: Sun, 17 May 1998 19:20:36 -0600
From: "mike newbold"
Thanks everybody for you help, my SST is now up and running. pulled the MV
209 and replaced with the MVAM108 varactor. now works from 14.052 to
14.063. my son added heat with a soldering iron and i pulled. the
toothpick won out over the dental tool clearing the hole. The monitor
volume is still too loud but i was happy to make my first qso with WD0GXI,
Wayne in Carthage Mo. 519 booth ways. tough copy but pulled off the
inaugural qso. second qso was with KE4DDI, Rick in Aiken, Sc. I got a 569.
The best part was when he sent "rig hr also SST great rig". after a 40
min. qso i tended to agree with Rick ... great rig. this is a great group
and thanks again to all who helped.
Catch a wave 72 73, Mike K YO
82. Subject: SST not quite there, help
Date: Tue, 12 May 1998 23:05:19 -0600
From: "mike newbold"
i just assembled a wilderness SST rev. B. The kit went together great
and is working, but in the digital portion of twenty mtr. i.e. 14.065 to
14.070. should be 14.050 to 14.060. Also I have to crank the AF almost
all the way to hear anything. And by then the monitor tone is way to loud.
Any one have any suggestions..... please.
Catch a
wave 72 73, Mike K YO newbold@cmn.net
Subject: SST BLUES NO MORE
Date: Sun, 17 May 1998 19:20:36 -0600
From: "mike newbold"
Thanks everybody for you help, my SST is now up and running. pulled the
MV209 and replaced with the MVAM108 varactor. now works from 14.052 to
14.063. my son added heat with a soldering iron and i pulled. the
toothpick won out over the dental tool clearing the hole. The monitor
volume is still too loud but i was happy to make my first qso with
WD0GXI, Wayne in Carthage Mo. 519 booth ways. tough copy but pulled off the
inaugural qso. second qso was with KE4DDI, Rick in Aiken, Sc. I got a
569.The best part was when he sent "rig hr also SST great rig". after a
40 min. qso i tended to agree with Rick ... great rig. this is a great
group and thanks again to all who helped.
Catch a wave 72 73, Mike K YO
83. Subject: Moving SST to 15mtrs
Date: Wed, 1 Jul 1998 13:01:40 -0600 (MDT)
From: marion@montana.com
I was easily able to move a 20mtr SST to 15 mtrs and it is
Working great. Changes to the VXO and output filter and XMIT mixer where all
That's required. Covers 21.050 to 21.070 with single varactor. Thought I would
Let those who had been thinking about it know it works great.
72 Roy AB7CE
Date: Wed, 1 Jul 1998 17:36:38 -0600 (MDT)
From: marion@montana.com
At 01:48 PM 7/1/98 -0600, you wrote:
>marion@montana.com wrote:
>>
>> I was easily able to move a 20mtr SST to 15 mtrs and it is
working
>> great. Changes to the VXO and output filter and XMIT mixer where all
thats
>> required. Covers 21.050 to 21.070 with single varactor. Thought I
would let
>> those who had been thinking about it know it works great.
>> 72 Roy AB7CE
Sounds good Roy! Do you think it could be made to work on 10 meters?
72, Tom WB5QYT
--
I have not explored this to a success. The component values at twenty
Were close enough to work at fifteen for most of the circuits, except those
Three cicuits. So far moving to ten has involved major circuit changes.
However, moving to 17mtrs is as easier than moving to 15mtrs. Roy AB7CE
84. Subject: Move 20mtr SST to 15mtr: component values
Date: Thu, 2 Jul 1998 11:26:25 -0600 (MDT)
From: marion@montana.com
DOZENS of requests on moving 20mtr SST to 15mtrs, so here is
how I did it. If you make changes or improvements other than these, please
let me know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO
VXO
X6 = 25mhz crystals. I used two, one on top, one under
board.
RFC3 = 23t #26 on T37-2(red). This was a critical value
for proper oscillation and range. You may have to adjust
a turn plus or minus, or compress or spread turns to
adjust to desired tuning range.
PA
2.2uh molded choke from base of Q2 to ground.
As above changes were all that was neccessary to put it on 21.050 to
21.070 with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341) for two
watts out. Its also very easy to move to 17mtrs by using same approach.
Good luck and 72. Roy AB7CE
85. Subject: sst vxo
Date: Thu, 2 Jul 1998 18:20:44 -0600 (MDT)
From: marion@montana.com
I put two crystals in both of my SST's to extend vxo range. One
Is 20mtrs and the other is one I moved to 15mtrs. With the MVAM108
varactors I was able to get about 20khz range. I was experimenting with different
varactors I had on hand. Was not getting much difference. Then I tried
a MV1404. WOW! The 20mtr version is covering from 14.013 to 14.064. The
15mtr version is covering from 21.039 to 21.073. Scope shows solid waveforms
across oscillator ranges. I don't know where to get them. They don't
show up in my cross reference, so I don't even know what they are rated as.
Mine were in a envelope of a dozen, that was in one of Dans Small Parts
20lbs of parts for $10.00. They are not listed on his current page. If any one
knows what they are rated or where to get them, they might inform the rest of
the list. 72 Roy AB7CE
86. Subject: SST sidetone
Date: Thu, 9 Jul 1998 12:53:57 -0600 (MDT)
From: marion@montana.com
After unsuccessfully trying various methods to reduce the
Sidetone on my SST, I decided to ask someone who knows the best way to go about
it. That someone was Wayne, N6KR, The rigs designer. The following info
works with mine with some values adjusted for best performance.
--------------
Hi Roy,
Usually there is a good balance between the incoming signals and the
sidetone in the SST. But you're right--if you have to turn it way up,
the sidetone gets loud.
The only sure-fire way to mute the sidetone to a lower level is to
insert a low pinch-off JFET like a J201 into each leg of the audio connection
from the product detector to the audio amp. This is how I do it in the
'40A. Actually you can probably find other JFETs that will work; J310s are
mostly low pinch-off, too. MPF102s will work if you hand-select them for low
pinch-off.
The source leads go to the '602 and the drains to the original capacitors
that go to the '386. Tie the gates together and add a 1 to 10M pull-up
resistor from the gates to one of the source leads. Next, connect a
diode from the gates to the key input. Test the circuit thus far by keying
the rig: you should hear ZERO sidetone at this point, because pulling the
gates low cuts off the JFETS, making them look like an extremely high
resistance. If you hear a click on keydown, put a resistor (start with 1K) in
series with the gate diode. If you hear a click on key-up, add a capacitor
from gates to ground; start with about 0.1uF and see if you can go smaller.
(It will depend on the pull-up resistor; 10M and .047 work well in most
cases.)
Once this much is working, you can add a resistor *across* one of the
JFETs (source to drain) to allow some sidetone to sneak through--as much or
As little as you want. It will take a large resistor, something like 1 to
15M in my experience.
Let me know if this does it! You might also post this message to QRP-L
If you have good results.
Thanks & 73,
Wayne
N6KR
-----------------------------
I was able to use some bargain J305s, no matching effort was
done. They completely muted the sidetone. I did not use the resistor to
bypass some of the tone, as I have the KC1 installed, so I use its sidetone.
In my case the pull up resistor is 2megohms, the capacitor to ground is
.1mfd. Keyline is a 1k resistor in series with 1N4148 switching diode. No
clicks or pops, smooth QSK. Did loose some of the ability to hear other stations
at the same time as in transmit, but don't have to juggle the volume all
the time now either. A big thanks to Wayne. 72 Roy AB7CE
87. Subject: moving SST to 15mtrs
Date: Fri, 10 Jul 1998 10:17:24 -0600 (MDT)
From: marion@montana.com
I recently posted info on moving 20mtr SST to 15mtrs. Heres
Another component change, RFC1 to 2.7uh(or close to it). Improves match to
Filter and recieve. 72 Roy AB7CE
88. Subject: TiCK Audio in SST?
Date: Tue, 14 Jul 1998 22:00:23 -0600
From: "Steve Galchutt"
Where did those of you who put a TiCK keyer in your SST hook up to the
Audio chain. I'm afraid of unbalancing my LM386 by dumping it in on pin 2 or
3?
Where is best? 72...Steve
______________________________________________
n0tu - solar powered QRP & wire antennas @ 7,200' ASL
Monument,Colorado - Grid Sq DM79nb
89. Subject: Mounting a Tick/K8+
Date: Sun, 19 Jul 1998 21:27:05 -0600
From: "Steve Galchutt"
Discovered a neat trick tonite.
While trying to install a Tick/K8+ style keyer in my SST, I saw I was
cramped for space and no room for my keyer which was made up on a
little piece of 1"x 1 1/2" perf board and needed a place to reside. Plus, I'm
thinking of adding some other goodies to the SST and want to leave
rooom for them. So I decided build another keyer and mount it on the back end of
the keyer jack(inside the case of course). I just epoxied the a 8 pin IC
socket to opposite end of the mounting hardware on the jack. And now I'm
wiring it up and hope to have it working for the BB event. Never dreamed I would
have a keyer almost smaller than it's paddle jack! How times change.
72...Steve
______________________________________________
n0tu - solar powered QRP & wire antennas @ 7,200' ASL
Monument,Colorado - Grid Sq DM79nb
90. Subject: Another SST lives
Date: Sat, 01 Aug 1998 18:00:12 -0400
From: Scott Bauer
Hi Group,
Finally, after moving to a new home, I have found
some time to finish building my 20 meter SST kit.
I did have some trouble getting the SST to operate
in the frequency range specified in the manual. After
swapping the 18 mhz crystal out a few times and
changing D4A to D4B, I managed to get a perfect
14.048- 14.061 range. With D4A installed, mv209,
the range was way too high.
The tinkering was well worth it as the SST is a
very nice little XCVR and Im very happy with the
performance.
I managed to work K5OT in the NA Contest. Grabbed
him on the first call. He must have a great station
to hear my 1.5 watts in all of that racket going on ;-))
Now back NA contest with the Teeny Tiny SST !!
What fun it is!!!
72, Scott
91. Subject: NC 40A versus SST - per N6KR Wayne
From: >
Sent: Wednesday, May 21, 1997 11:36 PM
Hi Jim,
The SST is a VERY small radio, something of a novelty. My primary
reason for designing it was to try a number of circuit simplification
ideas, but also to provide a radio that would fit in a small day-pack
as part of an ultra-lightweight station. With only 60% as many parts as a
40A it has some unavoidable compromises. But it also is availble on 30
and 20 meters, which the 40A is not.
Here's what you get for the extra $$ for a 40A:
* the 40A covers from 40 to 150kHz of the 40-meter band, while
the SST covers only 8 to 12kHz using its VXO. The 40A is still quite
stable since its VFO runs at 2MHz or so. The SST's design is more amendable
to use on the high bands.
* the 40A has RIT with on/off switch; no RIT on the SST
* the 40A has room on the front panel for the KC1, it's easy to
install; the SST has room in the top cover but the KC1 installation
will not be as easy or as clean
* the 40A has a bit higher power output, typically 3W (SST
typically 2W)
* the 40A has room for a 10-turn pot for the VFO-nice if you add
a turns counter or freq counter such as the KC1
* the 40A has a more sensitive receiver with more audio output
* the 40A has much better AGC than the SST (the SST's LED-based
AGC is cute but not high-performance)
* finally, the 40A comes with a painted and silk-screened case;
the SST has a plain aluminum case that you have to finish yourself
The SST is still fun to use and easy to build, as well as being the
smallest member of the Wilderness transceiver family and covering 20
and 30 meters. But if you don't need the ultra-small size and low
price-tag, or the higher bands, the 40A is a much better radio.
Hope this helps!
73,
Wayne
N6KR
92. Subject: AW: alternate crystals for SST/40
Date: Tue, 18 Aug 1998 20:39:29 +0200
From: "Peter_dl2fi"
I paralleled a second xtal (also from Wilderness, same frequency.
Tuning range is now 7023 to 7038. With an other L I had 7018 to 7034
Its somthing to experiment with.
72 de Peter
-----Urspr ngliche Nachricht-----
Von: owner-qrp-l@Lehigh.EDU [mailto:owner-qrp-l@Lehigh.EDU]Im Auftrag
von Allan Taylor K7GT
Gesendet am: Dienstag, 18. August 1998 19:45
An: Low Power Amateur Radio Discussion
Betreff: alternate crystals for SST/40
I have just purchased a SST/40m rig (from WA2HOQ). It is, of course,
centered around 7040. Has anyone successfully arranged a crystal
switching arrangement or socket to allow other center frequencies.
I am interested in occasionally trying 7020-7030 when out in the
sticks. (That's where the JAs are in the morning). Also, what is the
best sourc eof such custom crystals.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net.k7gt/index.html
93. Subject: Re: SST/40 bandwidth issues
Date: Wed, 19 Aug 1998 08:16:44 -0700
From: Allan Taylor K7GT
I hadn't thought the responses to my SST bandwidth query merited
posting ... but I was wrong! The three suggestions I have received
were:
1) put in a bigger reactor (I assume that means a bigger inductance,
but not completely sure). This approach tends to unstable freq, tho.
2) Put both varacter diodes in (apparently two were supplied with the
SST) with a switch allowing selecting which one to use.
3) Parallel two xtals (yes, identical freq) and a slightly wider
range is attainable. See Super-VXO on the web, 7L4? and G3YCC.
3A) Put in two different crystals, switch between them.
I intend to implement 2 in a test jig and if it isn't sufficient, try
3A.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net/k7gt/index.html
94. Subject: Tick keyer into SST
Date: Tue, 25 Aug 1998 15:53:51 -0700
From: Allan Taylor K7GT
For compatibility reasons, I have decided to put a Tick keyer (likely
the SuperTick Tick-3) in the SST. While it looks fairly
straightforward, I would like to hear from anyone who has done that. Exactly how did the keyer audio interface with the SST audio. Planning on 3V battery inside
to power the keyer, so no need for a 5V regulator from rig power.
Having not heard from anyone re a power mod for the SST, I will presume
to try one of my MRF237s in it instead of the 2N3553 and see if I can
get it up to 4W under full throttle.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net/k7gt/index.html
Subject: Tick inside an SST
Date: Fri, 25 Sep 1998 16:00:28 -0700
From: "Jim Knopf"
Has anyone here put a Tick keyer inside an SST?
If so, what values did you use for R2 and R3, which Embedded Research
Says are "rig dependent."
Any problems with using the default resistors supplied, which are for
The Norcal-40A.
.....
-Jim, KI7Q
mailto:knopf@halcyon.com
Visit the "Father of Shareware" at
http://www.halcyon.com/knopf/jim
95. Subject: Re: sst question... 8V to NE612's and LM386.
Date: Thu, 6 Aug 1998 23:34:01 -0600 (MDT)
From: Paul Harden
On Thu, 6 Aug 1998, Bernie Doehner wrote:
> Can't the NE602 (or in my case NE612) and LM386 handle a full 12-14
VDC?
>
> Doesn't driving the NE612's, and LM386's with full 12V produce larger
> swing, and thus louder audio??
Bernie,
The VCC range for the NE602/NE612 is 4.5v to 9v. 9v is the maximum
voltage that should be applied. However, running a 602 in the 8-9v
range, near it's maximum rating, draws more current and has a higher
noise figure. As a result, most designers limit it to 8v, or in some
cases, will insert a diode between the 602 and +8v to cause a 0.6v
drop to run it around 7v to be extra safe and lower the noise.
Applying 12v WILL fry it.
The LM386's are suitable for +12v operation.
The LM386 is rated for +4 to +12v
The LM386A is rated for +5 to +18v
On the LM386, you will often see a 100 ohm resistor between the Vcc
pin (pin 6) and +12v, bypassed with a .1 cap to ground. This is to
keep the current fluctations of the LM386 out of the dc power bus,
AND causes a slight voltage drop so it runs a bit less than +12v for
a slight measure of safety. The LM386A's are a bit more robust with
their 18v rating.
Sometimes running an LM386 from +12v can cause "motorboating." If
this should occur, then bypass the 100 ohm resistor to the Vcc pin
with a large value electrolytic (instead of the .1uF), or lower the
Vcc below 12v.
Your concerns are justified. Always operate passive and active
components well within their maximum ratings. As Gary Surrency noted
on a previous post, tantalums are known to leak, or outright "blow"
by exceeding their maximum rating by only a bit. Another common
error I see is the coupling cap between the PA transistor and the
output filter. At 5W, you have 47Vpp, and a capacitor with less than
a 50V rating will experience excessive heating. The same holds true
for the caps in the output filter. 16V dipped mica's will get hot,
increase the power dissipation, leaving far less power to actually
reach the antenna.
GL, Paul NA5N
Who's blown a few tantalums myself!
Subject: Re: sst question... 8V to NE612's and LM386.
Date: Thu, 6 Aug 1998 22:38:47 -0700 (PDT)
From: Bernie Doehner
> Bernie,
> The VCC range for the NE602/NE612 is 4.5v to 9v. 9v is the maximum
> voltage that should be applied. However, running a 602 in the 8-9v
> range, near it's maximum rating, draws more current and has a higher
> noise figure. As a result, most designers limit it to 8v, or in some
> cases, will insert a diode between the 602 and +8v to cause a 0.6v
> drop to run it around 7v to be extra safe and lower the noise.
> Applying 12v WILL fry it.
AH... The voice of reason. Thanks. 8V it is in the unmodified SST.
Shall leave it that - thanks..
> The LM386's are suitable for +12v operation.
> The LM386 is rated for +4 to +12v
> The LM386A is rated for +5 to +18v
>
> On the LM386, you will often see a 100 ohm resistor between the Vcc
> pin (pin 6) and +12v, bypassed with a .1 cap to ground. This is to
> keep the current fluctations of the LM386 out of the dc power bus,
> AND causes a slight voltage drop so it runs a bit less than +12v for
> a slight measure of safety. The LM386A's are a bit more robust with
> their 18v rating.
Not in the SST design, it goes to the 7808 instead..
> Sometimes running an LM386 from +12v can cause "motorboating." If
> this should occur, then bypass the 100 ohm resistor to the Vcc pin
> with a large value electrolytic (instead of the .1uF), or lower the
> Vcc below 12v.
I may try this to see if I can get a bit more audio out of it, thanks
For the warning though.
> Your concerns are justified. Always operate passive and active
> components well within their maximum ratings. As Gary Surrency noted
> on a previous post, tantalums are known to leak, or outright "blow"
> by exceeding their maximum rating by only a bit. Another common
> error I see is the coupling cap between the PA transistor and the
> output filter. At 5W, you have 47Vpp, and a capacitor with less than
> a 50V rating will experience excessive heating. The same holds true
> for the caps in the output filter. 16V dipped mica's will get hot,
> increase the power dissipation, leaving far less power to actually
> reach the antenna.
:)
Oh yes... Thanks!
Bernie
96. Subject: Tick keyer into SST (Perhaps Allan now knows how.)
Date: Tue, 25 Aug 1998 15:53:51 -0700
From: Allan Taylor K7GT
For compatibility reasons, I have decided to put a Tick keyer (likely
the SuperTick Tick-3) in the SST. While it looks fairly straightforward,
I would like to hear from anyone who has done that. Exactly how did the
keyer audio interface with the SST audio. Planning on 3V battery inside
to power the keyer, so no need for a 5V regulator from rig power.
Having not heard from anyone re a power mod for the SST, I will presume
to try one of my MRF237s in it instead of the 2N3553 and see if I can
get it up to 4W under full throttle.
Have a 2nd op (N6RY, Terry) for the Sept 18,19 Yosemite QRPxpedition to
Grid squ DM07, Hayden Lake (elev ~7700') overlooking the Tuolumne River
canyon. Should give us a great shot at EU on 20m. Can't wait!
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
97. Subject: SST fine tuning mod?? (Perhaps Allan now knows how.)
Date: Mon, 31 Aug 1998 10:30:15 -0700
From: Allan Taylor K7GT
Is there a 3-turn or 10-turn pot that will fit in the space of the
existing tuning pot in the SST? It looks cozy to me and would like to
know if someone has done this potential mod.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
98. Subject: SST Labeling (Perhaps Rick now knows how)
Date: Fri, 04 Sep 1998 22:00:07 EDT
From: wa8rxi@juno.com (Rick Arzadon)
Fellow QRP fans;
Built an SST and would like to paint and label the case.
In the manual is artwork for 1:1 copy to a transparency.
The question is...... How do I glue this clear plastic to the case?
TNX ES 72, Rick Arzadon - WA8RXI Taylor, MI.
Date: Tue, 29 Sep 1998 18:01:31 -0500
From: "Karl Heimbach"
To:
Gang,
I'd like to try a parallel HC-49 11.046 MHz microprocessor crystal in a 40m
SST in an attempt to increase the tuning range. My Mouser catalog does not
show it to be a stock item.
Anyone have an idea of where I might get one?
Thanks,
Karl - W5QJ
Subject: Re: 40m SST Crystal
Date: Tue, 29 Sep 1998 16:18:53 -0700
From: "Allan (Grant) Taylor"
The crystal in question is a Digikey X025-ND.
I have already checked with International Crystal Mfg Co. with the intent
of obtaining a few additional crystals to allow coverage down-band.
Those crystals will cost $13.68 each, plus UPS charges. I can get you
Further info if you would like regarding that option. I am contemplating
instead getting a 2nd NC40A, then repackage the new NC40A for field
use (pots on top, etc.)
K7GT
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
100. Subject: SST-40 VXO expanded range - component values
Date: Mon, 5 Oct 1998 22:51:23 -0500
From: "Karl Heimbach"
To:
Gang,
I've read with interest the "Wilderness SST Notes" on G3YYC's webpage. Of
particular interest has been the commentary on expansion of the VXO tuning
range. Perhaps the following may be of interest to others wanting to expand
the range of their SST-40.
Tabulated below are results of a couple of combinations of crystals and
inductors and the tuning range observed with each combination.
In all cases, the X6's were 11.046 MHz HC-49's (DigiKey X025-ND) and RFC3's
were molded epoxy chokes.
Case: Design 1
RFC3 value: 15 uh 15 uh
# of X6's: 1 2
Tuning: 7.034-7.041 6.9814-7.0319
Range: 7 KHz 50.5 KHz
Case: 2 3
RFC3 value: 13.2 uh 13.2 uh
# of X6's: 2 3
Tuning: 7.019-7.040 6.949-7.035
Range: 21 kHz 86 KHz
Case: 4
RFC3 value: 11 uh
# of X6's: 3
Tuning: 7.007-7.042
Range: 35 KHz
I stopped with Case 4. RF output is approximately 3 watts throughout the
tuning range with a clean sine wave also observed throughout the range. On
air reports have been good.
Karl - W5QJ
101. Subject: RE: LM386 question answered
From: Ed Loranger [SMTP:we6w@qsl.net]
Sent: Tuesday, October 13, 1998 2:08 PM
Subject: RE: LM386 question answered
Howdy Alan et. al: You got this a bit wrong :)
I mentioned that the 220 to 470 uF Electrolytic
go from the +V input to the LM386 and Ground.
Not the 1/8 pin feedback network.....
I hope this opens up some ideas for you.
GL OM.
-Ed
K7GT mentioned:
A higher Vcc does allow wider swings in the case of high input
signals.
So, on that basis rerouting Vcc rather than regulated (+8V in my case
with the SST) to the chip may help a little on strong signals. Another
suggestion (WE6W) was to put in a HUGE capacitor across pins 1-8. It
would seem the effect of that would be to make sure the internal
biasing network is REALLY out of the picture.
--
72, Ed WE6W (CW only/VP-0); http://www.qsl.net/we6w Santa Rosa, CA
QRP-Z#106 QRP-L#1068 AR#112 NC#2227 ARCI#9397 QAA#006
102. Subject: New rigs (SST versus OHR type rigs) de AL7FS
Date: Sat, 07 Nov 1998 10:44:51 -0900
From: Jim Larsen AL7FS
Rod Cerkoney wrote:
> I'm going to build a single bander, and it will probably be the
> Wilderness SST for 20 MTRS. IT'S CUTE!!! 73, Rod Cerkoney, K0RWC, Ft
Collins,
> CO.
Hi Rod,
Let me throw one more thought at you. I do think you will miss the RIT
on the SST. The SST is probably a good rig but may I suggest the OHR100A for
a first kit monobander? OHR makes great kits with great manual and great help
if you need it and the rig gives great functionality. In the long run, I
think you will like it better than the SST.
Let me try to find some additional info for you on the SST. Also, I
have posted a large set in info on the SST on the G3YCC home page.
http://www.homeusers.prestel.co.uk/g3ycc/
http://www.homeusers.prestel.co.uk/g3ycc/sst1.html
================
Subject: AL7FS - 1998 Flight of the Bumblebees
Date: Sun, 26 Jul 1998 21:03:48 -0400
From: "Wilford D. Lindsey" <70511.3041@compuserve.com>
Jim:
I believe I heard you one time....and even called you 2X. But no joy.
Nuts. Sure always hope to QSO with you :-). Well maybe another time.
Rig(s) at my /BB QTH were Sierra and SST-20. Would have used the SST
more, but without RIT it became next to impossible unless the guys
called me just right for the offset frequency. So when it goo too
rowdy,I quickly switched to the Sierra.
Man if only RIT could be added to the SST! Bob N4BP wondered in a
recent post about putting one where the RF control is on the back.
Hmmm...
Anyway, glad you had a good time. CUL.
72/73,
--Doc Lindsey/K0EVZ Rochester, MN--Home of the Mayo Clinic.
=======================================
From: >
Sent: Wednesday, May 21, 1997 11:36 PM
Subject: Re: A Question
Hi Jim,
The SST is a VERY small radio, something of a novelty. My primary
reason for designing it was to try a number of circuit simplification
ideas, but also to provide a radio that would fit in a small day-pack
as part of an ultra-lightweight station. With only 60% as many parts
as a
40A it has some unavoidable compromises. But it also is availble on 30
and 20 meters, which the 40A is not.
Here's what you get for the extra $$ for a 40A:
* the 40A covers from 40 to 150kHz of the 40-meter band, while
the SST covers only 8 to 12kHz using its VXO. The 40A is still quite
stable since its VFO runs at 2MHz or so. The SST's design is more
amendable to use on the high bands.
* the 40A has RIT with on/off switch; no RIT on the SST
* the 40A has room on the front panel for the KC1, it's easy to
install; the SST has room in the top cover but the KC1 installation
will not be as easy or as clean
* the 40A has a bit higher power output, typically 3W (SST
typically 2W)
* the 40A has room for a 10-turn pot for the VFO-nice if you add
a turns counter or freq counter such as the KC1
* the 40A has a more sensitive receiver with more audio output
* the 40A has much better AGC than the SST (the SST's LED-based
AGC is cute but not high-performance)
* finally, the 40A comes with a painted and silk-screened case;
the SST has a plain aluminum case that you have to finish yourself
The SST is still fun to use and easy to build, as well as being the
smallest member of the Wilderness transceiver family and covering 20
and 30 meters. But if you don't need the ultra-small size and low
price-tag, or the higher bands, the 40A is a much better radio.
Hope this helps!
73,
Wayne
N6KR
=============================================
Well, there is more but this should help continue to fill your mind
with more
stuff than you probably wanted. Good luck
73, Jim, AL7FS -- Anchorage, Alaska
(BP51cc)@61.1009636 North 149.8237915 West(approximately)
mailto:al7fs@qsl.net ICQ 11022915
103. Subject: NC 40A versus SST - per N6KR Wayne
Date: Fri, 7 Aug 1998 15:28:32 -0800
-----Original Message-----
From: >
Sent: Wednesday, May 21, 1997 11:36 PM
Subject: Re: A Question
Hi Jim,
The SST is a VERY small radio, something of a novelty. My primary
reason for designing it was to try a number of circuit simplification
ideas, but also to provide a radio that would fit in a small day-pack
as part of an ultra-lightweight station. With only 60% as many parts as a
40A it has some unavoidable compromises. But it also is availble on 30
and 20 meters, which the 40A is not.
Here's what you get for the extra $$ for a 40A:
* the 40A covers from 40 to 150kHz of the 40-meter band, while
the SST covers only 8 to 12kHz using its VXO. The 40A is still quite
Stable since its VFO runs at 2MHz or so. The SST's design is more amendable
to use on the high bands.
* the 40A has RIT with on/off switch; no RIT on the SST
* the 40A has room on the front panel for the KC1, it's easy to
install; the SST has room in the top cover but the KC1 installation
will not be as easy or as clean
* the 40A has a bit higher power output, typically 3W (SST
typically 2W)
* the 40A has room for a 10-turn pot for the VFO-nice if you add
a turns counter or freq counter such as the KC1
* the 40A has a more sensitive receiver with more audio output
* the 40A has much better AGC than the SST (the SST's LED-based
AGC is cute but not high-performance)
* finally, the 40A comes with a painted and silk-screened case;
the SST has a plain aluminum case that you have to finish yourself
The SST is still fun to use and easy to build, as well as being the
smallest member of the Wilderness transceiver family and covering 20
and 30 meters. But if you don't need the ultra-small size and low
price-tag, or the higher bands, the 40A is a much better radio.
Hope this helps!
73,
Wayne
N6KR
104. Subject: SST Question - higher SWR with SST than with other rigs
Date: Wed, 20 Jan 1999 09:24:17 -0600
From: "Robert Radtke"
Hi All -
I just finished building a Wilderness SST Kit (my first kit - yeah!!!!)
And everything worked great straight out of the box. I have 2 questions
though.......
1. I had a very hard time running it through my MFJ tuner. I got a much
higher SWR when running the SST than with my other rigs (Kenwood 520
and Heath HW-7). When I adjusted the tuner to lower the SWR, I couldn't
hear nearly as much as when I bypassed the tuner. What's happening?????
Is the antenna impedance from the SST something very different that
50ohms? Is the tuner just sucking up that much RF in it's circuitry?
Any ideas would be great.
Thanks in advance,
Robert Radtke - KC0EJW
====
Date: Wed, 20 Jan 1999 07:46:52 -0800
From: "Roger A. McCarty"
Hi Robert,
You have one or two problems. Either your output frequency is much
Different than the band for which it was built and/or you are transmitting a
number of harmonics and spurs. If you have a scope, it would be simple to
determine if or which. You want to see a very clean sine wave on the output and of course at the freq for which the rig was built. A tell tale sign of
spurs/harmonics is your watt meter will indicate significantly more power than the unit is designed to deliver.
I don't know if the SST has a drive control, but if so try backing way
Down on it and see if that helps with the output waveform. If the SST
Sidetone monitors actual RF (Others experienced with this rig can comment here)
Back down on the drive control until the sidetone sounds clean. Also, if you
Have another radio at your disposal, listen for the signal to be clean and
crisp. If it is raspy and/or you hear the signal up and down the band, you
have spurs/harmonics.
If any of these effects are present, the most common problem is in the
output filter of the rig. Check all of your connections and coils in
the filter. Drive stage problems are also suspect. These are generalized
troubleshooting techniques, others may have specific pointers for the
SST.
Good Luck
Roger KD6CC
==
Date: Wed, 20 Jan 1999 22:56:48 -0600
From: Robert Radtke
Hi again -
I just wanted to say thanks for all of the help. After several hints
about harmonics, I tuned my Kenwood up to 20M and heard the 40MSST loud
and clear.
I checked on the toriod windings and realized that I had switched the
number of turns with the inches of wire number -- duuuhhhh :{ - sooo
after desoldering and rewinding everything it worked great.
I fired it up and got PA and OH right away from Minnesota - both QRP -
QRP.
Thanks again for the help --
Robert - KC0EJW
105. Subject: Wilderness SST Troubles! touch the cap output jumps
Date: Tue, 2 Feb 1999 01:08:44 -0600
From: "Nathan Odle"
Hey gang,
Wondering if any of you could help me troubleshoot my newly-built 30M
SST. My problem is that output seems to be very low until I go to peak C28 -
At that point, the minute I touch the cap output jumps (at least as far as
I can tell on the monitoring receiver). I also notice really low
Background noise from the SST receiver. Is this characteristic? Any help will be greatly appreciated...TNX es 73
Nathan
KB0NNV
==
Subject: Sick SST. I'm about to go crazy...
Date: Wed, 3 Feb 1999 22:20:46 -0600
From: "Nathan Odle"
To all of you technically adept QRP-L members:
OK, STILL have major SST probs. It's the 30m version. This is really
getting frustrating, folks. Here's the situation:
1. No real output to speak of from the antenna jack. I listen to the
SST on a Yaesu FT-990 and hear a small signal that doesn't even deflect the
S-Meter. It seems to be covering the correct frequency range though.
Adjusting C28 has no effect, except when you touch it with a metal tool
The S-meter on the 990 jumps to about a 5. The only meter I have around
That even gets close to what I need for this is an old Palomar 500 (hey, I'm
broke) that I think was used for CB once upon a time (before my day).
Even on the 0-10W range, the needle doesn't budge.
2. Not hearing anything but my own signal (and yes, I was plugged into
an antenna - a Mosley beam). When the volume is cranked, I hear a little
hiss, nothing else. I can't peak C1 because I don't hear anything - even on
a band FULL of nice signals. The FT-990 was hearing all kinds of good
sigs without an antenna even plugged in. I can, however, hear the 990 when
it's RIGHT NEXT TO ME and transmitting into a dummy load (on the same Freq I
hear the SST on - the TX/RX is not shifted). The AGC light sometimes
flickers when this is happening...and also rarely flickers when I transmit.
3. A thorough check of the DC voltages on the ICs as given by the
chart shows everything is pretty much within parameters, except for the
following places (checked with my Fluke DMM):
Rcv:
Spec Measured
---- --------
Q1-S: 0.9 1.9 !
Xmit:
Spec Measured
---- --------
U1-1 -0.5 1.1 !
U1-2 -0.9 0.8 !
U2-5* 7.6 8.0 ?
U4-4 6.8 6.4
U4-5 6.8 6.3
U5-2 7.2 6.9
U5-7 13.7 13.8
Q1-S: 0.9 1.9 !
Q2 **
! = Big discrepancy
? = Not a big discrepancy, but it was identical on transmit and
receive.
The numbers say it's supposed to drop on TX.
* When the probe is touched to this point, the little bit of noise that
IS coming out of the headphones goes mute.
** Even though the manual says voltages on Q2 can't be measured because
of loading by DMM probe, not even the slightest output is seen anyway
(shouldn't one see at least SOMETHING?)
4. Other notes: VXO is covering 10.105 - 10.118. Also, the power
supply is a good Astron that shows exactly 13.8v on my DMM.
I am using stereo headphones, I've checked the toroids for continuity
(poorly stripped leads) and correct winding, X6 is NOT confused with
the others and the filter XTAL cans are properly grounded, The ICs are in
correctly, none of the electrolytics are in backwards, the molded
inductors are in the right places, as are the trimmer pots, and ALL of the other
parts for that matter (I double-checked the ENTIRE parts list to verify parts
placement just now). D4 is the MV209, but it was exhibiting the
problem with the other varactor as well. There are no broken traces that I can
see.
I have also checked the solder joints thoroughly - nothing wrong there
either - no bridges, cold joints, etc...
I hope someone can help me with this...I'm at my wit's end. I admit
I'm don't know as much about this stuff as I'd like to, and hope it's not
something really stupid. I've told you everything I know about the
situation, hope it's enough for a solution. I was planning to show it
at our meeting on the 9th, hopefully it'll be running before then...
Thanks in advance for any of your assistance...I really don't want to wind up
Paying the "flat fee" price of $50 + shipping that I don't have, just to get
This rig going.
TNX es 73,
Nathan
KB0NNV
==
Date:
Thu, 4 Feb 1999 00:03:46 +0000
From:
"Steven Weber"
To:
"Low Power Amateur Radio Discussion"
> 1. No real output to speak of from the antenna jack. I listen to
the SST
>
> 2. Not hearing anything but my own signal (and yes, I was plugged
into an
Sounds to me there isn't any continuity through the low pass filter.
Make sure the enamel is scraped clean off the magnet wire and the
solder stuck to it well. A real common problem..
If that's not it, good luck, but a real good look over for solder
shorts, those pesty little metal shavings caused by insterting parts
in the holes, or open pcb tracks would be a good start.
BTW, If you get too fustrated, I'll fix if for shipping costs (and
parts if needed), just to get a good look at one...
72,
Steve, KD1JV in the white Mountains of New Hampshire
"melt solder"
==
Date: Thu, 4 Feb 1999 16:37:07 EST
From: RangerSF5@aol.com
Hi Nathan,
I read you'r post on the SST that you have problems with.
I'l skip all the mumbo jumbo since it looks like you double checked
everything.
I just want to say that I built 5 for myself and 2 more for others.
The SST is a fine rig but when it comes to tuning,(peaking) you have to
go
REAL SLOW.
Ok you made all the checks and this is what i'm looking at.
1 You discovered a chip that does not pull down the voltage on one of
the pins
of *U2*
2 The tone you hear is your transmitted RF (Just about nil).
3 The red *LED* you say is flickering Sometimes)
4 You have RX noise (good sign)
5 You said that when you touch the pin,your big rig will pick up the
transmitted signal but you did not say if the red *LED* came on with
it.
At this time,i'd say that the *U2* is the problem.
BTW the way,
Most of the SST rigs I built,I used sockets for the chips.
If you bake one,it's an easy change.
I noticed no difference when using the sockets.
It's a good way for a Newbie to build the kit/s and when all seems to
Be working well,clip the pins on the sockets and remove them 1X1 then
solder in the chip.
I also found the extra diode for the extended VXO range to be the most
stable.
Put you'r findings on the reflector.
GL
72/73
Bob
WA2HOQrp
==
Subject: SST *might* be fixed...we'll see for sure tomorrow!
Date: Fri, 5 Feb 1999 00:07:07 -0600
From: "Nathan Odle"
OK folks, thanks for all of your helpful messages. I started going
backwards from the non-antenna jack side of the low-pass filter with a
metal tool while the 990 transmitted into a dummy load, and noted where the
signal dropped off. I found one of the solder pads of L3 to not give a loud
response when I touched it like the other ones had. When I hit the
wire end dead-on with the tool (like I did when testing for continuity), I got a
signal, but when I touched the solder around it as well as components
more toward the antenna jack I got hardly anything. So, probably bad solder
joint. I reheated the joint and this appears to give some improvement
(RX audio is definitely up a bit), but I'm going to pull out that toroid
and redo the whole thing tomorrow just to be sure. Then, I can finally
test!
I'm going to St. Louis in the evening, so it looks like I might just
have 5 minutes or so to test it while there are sigs down there in the bottom
of 30m before I leave after work. I'll keep you guys posted. Man, if
that's all it winds up being I'm gonna be pretty disappointed with
myself...shame shame on me for overlooking that. But who knows, it could be that
that's not the problem and then we'll have more to talk about ;) Thanks again
guys...by the time I'm done with this I'll sure have learned a thing or
two!
TNX! es 73,
Nathan
KB0NNV
==
Subject: More on SST...
Date: Fri, 5 Feb 1999 00:12:51 -0600
From: "Nathan Odle"
Oh, and I'm pulling about 400mA on TX...is this enough to assume the
final's getting into the picture? I was running the PS at about 13v (makes
5.85W), so assuming 55-60% efficiency this puts me into the ballpark, doesn't
it (assuming some of that is being used for receive audio)?
73,
Nathan
KB0NNV
==
Date:
Thu, 25 Feb 1999 22:34:41 -0600
From:
"Nathan Odle"
To:
"Low Power Amateur Radio Discussion"
Some of you may remember my Sick SST posting some time ago. Well,
there's
good news and there's bad news. The good news is, the RX is great.
Seems
like it's performing wonderfully. The bad news is, the TX isn't doing
well
at all. I hear my own signal when I transmit, so the oscillator chain
seems
to be working, but my newly-built (and tested!) OHR WM-2 shows no
output.
Nil, zip, nada. I started probing around. There's no major
discrepancies
on U5 (the LT1252 driver) when I checked the DC voltages on the
troubleshooting table. Pin 6, which to me looks like the output, shows
about 9v of DC voltage, which drops somewhat on TX, just as it's
supposed
to. This pin 6 is connected to C31. I get the same voltages at the
Pin 6
side of C31, then NO DC voltage on the side of C31 that connects to R12
the
drive potentiometer. I'm not familiar enough with this to know if this
is
correct, but it doesn't seem to be right to me. I checked the solder
joints
on both legs of C31 and they're fine. Can anyone help out with this?
Thanks in advance for any help...
73,
Nathan
KB0NNV
==
30m SST Update
Date: Mon, 1 Mar 1999 10:27:07 -0600
From: "Nathan Odle"
Gang,
I posted some problems with my SST awhile back, and have been trying to
troubleshoot it when I get a chance. I was asked to let the group know
what the situation was, so here goes:
The inital problem with a lack of TX AND RX. On the RX side, with the
volume cranked full CW I could hear a slight hiss, so I knew the audio
amp was working. On the TX side, I knew the oscillator chain was good,
because I could hear myself on the monitor receiver, but no output from the
antenna jack. This pretty much narrowed the problem down to the output filter
-
it's involved in RX and TX, and it's after the oscillator chain.
A thorough check revealed something I missed in the first couple of
looks at the problem - one of the toroids was open. I missed it earlier because
I had inadvertantly been touching the DMM probe to the end of the wire
(and found continuity), but later discovered there wasn't any continuity
between solder pads. Checked ALL the solder pads again just to be sure, but
the one was all that had a problem. Out came the toroid - I rewound it for
good measure, stripped the ends VERY carefully, and reinstalled. Flipped
the power on, and was greeted by the beautiful sound of atmospheric noise.
All was well, or so I thought. Tried keying the rig, STILL no TX output.
Rechecked solder pads, the zener diode, drive pot, and C31. All A-OK.
Finally pulled Q2, the final transistor. Made a check (according to
directions from Mike Heitmann - N0SO), and discovered it was open.
Mike seemed to think it was probably a result of the mismatch created by the
Open toroid in the output filter. I have a replacement 2SC799 on the way,
Along with one of the ECG parts mentioned in the manual. Going to try the
hopped-up ECG-series and see how it does. If it doesn't work out, I'll
install my replacement 2SC799.
So there you have it. Hopefully this info will help someone out. I'll
Let you all know if the SST comes to life as soon as the transistors get
here! Hopefully not long thereafter you'll hear me on 30m QRP...
73,
Nathan
KB0NNV
==
Subject: SST Lives!
Date: Mon, 1 Mar 1999 23:49:14 -0600
From: "Nathan Odle"
Well, as I noted before I had narrowed my SST's TX problem to a bad
Final transistor. I ordered up a replacement last night, as well as a
Compatible "hop-up" part with more gain. Tonight, I was sitting around getting
impatient so I started searching for a suitable replacement in the
shack.
After looking and looking I finally came across an old Regency VHF
Business band radio. I decided that might be a likely prospect for the power I
Was looking for (it put out about 5w), so I popped open the case and traced
Back from the RF jack to find the final. I find the final, it's marked with
Motorola's logo - and is numbered "696-3", and below that "536". Now I
don't know a LOT about transistor markings, but I assumed this to be an
MRF536. I search for this online, and discover a listing that shows
This transistor to be close to what I'm after (at least somewhat similar to
The 2SC799 that comes with the SST). I pop this thing in, make my solder
joints, turn on the SST, key down, and WOW! I'm greeted with the
swinging needle of my OHR WM-2. Showing about 1.5w out. Not stellar, to be
sure, but more than adequate until my ECG-341 gets here. Yippee! Woohoo! My
first kit radio is on the air! Now I just need to get the Gap vertical
up for 30m...until then I'll just drag the rig into the club station ;)
Now, I could have been wrong about the transistor markings and just got lucky
-
would any of you guys that know more about this than myself (and might
also have a transistor data manual) care to comment??? Also, some
verification that this part is at least temporarily happy with it's new living
arrangements would be nice... From a newbie's perspective, coming up
with something like this is the highlight of the week...
73,
Nathan
KB0NNV
106. Subject: N4BP request for info SST Sidetone-answer?
Date: Mon, 08 Feb 1999 07:25:55 -0900
From: Jim Larsen AL7FS
Date: Mon, 8 Feb 1999 03:55:51 -0500 (EST)
From: Bob Patten
Any SST experimenters out there? The sidetone pounded my ears
mercilessly. How do I reduce the signal level hitting the RX stage?
Anyone play with RIT for this rig? This nearly cost me some contacts
on the edge of my bandpass. I'm reluctant to tune them to the center of
the passband since they might not be able to hear me come back. Jim, FS -
that's why I had such a tough time with you. Your signal was quite
good, but outside my passband.
73,
,'' '',
Bob Patten, N4BP ( 0 0 ) Plantation, FL
________________________________oOOo-(_)-oOO___________________________________
E-Mail: n4bp@bc.seflin.org
Web Page: http://wg104a.wh.uni-stuttgart.de/~n4bp
Brass Pounder BBS: (954) 472-7715
107. Subject: Varicaps for use in SST wide coverage VXO & 15 mtr conversion
Date: Sat, 13 Feb 1999 08:38:51 -0900
Jim Larsen AL7FS
Subject: Varicaps
Date: Fri, 12 Feb 1999 21:58:11 -0700
From: Roy
A few folks on the list have asked me about the MV1404
varactors I used in my SSTs to create wide coverage VXOs. I had some on hand to try, but didnt know where to get more. I just saw that RF Parts has them for
$6.95 apiece. Expensive(in my opinion, since I got a dozen in a Dans Small
parts 10lbs of parts for 10 dollars, shipped) but available. They work in
SSTs really well, I haven't tried them in any thing else. My 20mtr SST
Covers from 14.003 to 14.065. My 15mtr SST covers 21.015 to 21.068. I had to
Put ten turn pots in them. Anyway, just passing along along the info. Back
To working DX on my K2. 72 Roy AB7CE, Montana.
108. Subject: SST Mods from W9AC, Paul
Date: Wed, 03 Mar 1999 18:43:17 -0900
From: Jim Larsen AL7FS
Date: Wed, 03 Mar 1999 16:11:40 -0800
From: "Arthur G. Silvers"
Thanks Paul,
I have an SST for 20 mtrs and I am also using the switched varactor
diodes for increased range. Have all I need for the parallel xtal mod
but have putted that one off for the time being.
I hope you don't mind but I am posting your response as it may be of
interest to others.
72/73 es CUL Arth W6AGS
"Long Live Continuous Wave (LLCW)"
Paul Christensen wrote:
>
> Thanks for the compliments Art. I had a plating company in Tampa
anodize the aluminum in two colors: cobalt blue and black. The anodizing
looks better than any paint job I've seen, but it's an expensive process.
>
> My SST has several mods:
>
> 1) I added the TiCK keyer chip but used a novel method of dropping
+12 VDC to the TiCK's required input voltage by using two LED's in series to
create a constant voltage drop. As a side benefit, the LED's light in
sequence with keying (i.e., as current is drawn from the TiCK).
>
> 2) Added ABX I.F. filtering using the Sierra method.
>
> 3) Extended VXO range on 40-meters by paralleling two VXO crystals.
My range is now 7010 kHz to 7060 kHz using two switched, varactor
diodes.
>
> A description of my mods are available on the G3YCC QRP web page.
>
> -Paul, W9AC
>
> ----- Original Message -----
> From: Arthur G. Silvers
> To:
> Cc: qrp-l
> Sent: Wednesday, March 03, 1999 11:27 AM
> Subject: RE: Paddles
>
> >Paul,
> >
> >Looks as though you have done some interesting mods to your SST.
Care to
> >give us a few details? Nice paint job too.
> >
> >Tnx es 72/73 Arth W6AGS
> >
109. Subject: SST es KC1
Date: Mon, 15 Mar 1999 14:40:27 -0600
From: "Nathan Odle"
OK, had a quickie building session last nite and put together my new
KC1 that's going to go into the 30m SST. In the manual, Bob says that the
Best place to mount the KC1 is in the top half of the case, along the left
Side of the rig (over the xtal filter), with the speed adjustment closest to
The front. That's all fine and dandy, but I don't really like that idea
Because I'll have knobs sticking out of the top of my rig, and not only that,
But they'll be along just one side. That being said, does anyone have
experience with or thoughts on the following two options:
1) Mount the KC1 in the top of the rig, but mount it parallel to the
front panel, with the speed control lined up with the volume control. This
would put the keyer over the VXO though - is this a problem??? There would
be about 3/16" clearance.
2) This to me is the more desirable option. Replace the 10k pot with
a remote mounted one - mounted over the top of the keyer jack. Mount the
two momentaries over the RF and Power jacks. Then, if possible, run these
connections and the board connections to a header. Wire up the mating
plug to this header to the KC1, and 3M double-stick tape the KC1 to the top
panel, plugging in the header before I put it together.
Any ideas/comments/suggesions?
73,
Nathan
KB0NNV
==
Subject: Re: SST es KC1
Date: Wed, 17 Mar 1999 01:41:05 +0100
From: hw.merz@t-online.de (Hanns W. Merz)
Hi Nathan,
I have built a 20m SST with the KC1 in the front panel of the rig (NOT
in the top half). This is possible if you prepare the KC1 board for horizontal
mounting. The pots and switches have to be soldered horizontal, too.
Some leads must be changed therefore. It's a little bit a puzzle work but the
result is nice and it works fine. No problems with processor noise or something
else. But I wouldn't recommend this method if you have too big fingers ;-) as the
handling of the knobs could be a little bit difficult when operating allthough I
have arranged the knobs primarily for easy use rather than for best looking.
If you are interested I can try to take some digital pictures of my SST
and send them to you as JPG files.
72,
Hanns, DK9NL,
AGCW #1966, DL-QRP-AG #Foundation Member, G-QRP #6365, RIA #894
e-mail: hw.merz@t-online.de
---------------------------
The Wilderness Radio Sierra is my favourite QRP rig!
===============================================
110. Subject: SST VS SW30
Date: Sat, 3 Apr 1999 08:22:20 +0500
From: Tim and Aretta Gordish
>Does anyone prefer the SST over the SW30 as a 30 m rig?
>
>======================================
>Todd M. Carpenter, N9YSQ
>President ISUARC
>Member: WVARA, THRC, GQRP, INQRP, ARCI
>
I have built the SST-20 and the SW40, and the differences in the two rigs I
built are:
SW+ Loud, seemingly 3D audio, low sidetone, big tuning range.
SST Low volume audio, loud and clear sidetone. Nice tiny size. Easier
construction.
Both put out about 2.5 watts of clean signal, and work great. Which do I
prefer....Both!
73 de Tim
KB9LGJ
QRP-L #457 MN-QRP NORCAL FISTS AR-QRP
==============================================================
111. Subject: SST warble - Too big capacitor?"
Date: Sat, 10 Apr 1999 13:40:35 -0800
From: Mighty Mik
I managed to pick off the Spring Boquet station today, who gave me a
'557'...and said later that i have a 'warble'...I was on the NC20, which
is all stock EXCEPT i put a bigger cap in the VFO, so i could use it
with a 6M transverter (47pF...gives me a range of 14.000-194). I only
have 2 QSOs on it at this point...so i'll be looking to get this ironed
out before QRPTTF. anyone have ideas, comments?
i'm waiting on my new case before i do the AGC mod.
=====================================
112. Subject: SST 20 Tuning Range - More!
Date: Mon, 12 Apr 1999 09:54:31 -0700
From: "Arthur G. Silvers"
Fellow QRPers,
I know we are all into NC20s and other projects, but I just wanted to
relate my latest improvements on the tuning range of my SST 20 with
appropriate credit to those who have posted there results to QRP-L.
In order to improve the tuning range of the rig, the first thing I did
was to install both varactor diodes. This resulted in rather narrow
ranges for both diodes;
MVAM108 about 9 kHz
MV209 about 6 kHz.
I could have stopped there because I had the QRP calling frequencies
nicely covered. Spurred on by the success of other SST builders, I
installed the second parellel crystal and lowered RFC3 to 4.7 uH (a
standard value). This resulted as follows;
MVAM108 14.024 - 14.046
MV209 14.049 - 14.060
Hmm! Interesting improvement, but now the QRP calling freq is only
marginally covered and there was still an annoying gap in coverage
between the two diodes. Then Wayne Burdick suggested that I reduce the
value of R5, thus providing a wider voltage swing accross the varactors,
to 9K from 100K. I though that a bit radical so I first tried reducing
the resistance to half (50K) with the following results;
MVAM108 14.022 - 14.048
MV209 14.048 - 14.061
Now that is promising results and motivated me to reduce R5 as Wayne
recommended. So with a shunt 10K accross the original 100K, the net
resistance is of R5 is 9K which resulted as follows;
MVAM108 14.022 - 14.050
MV209 14.041 - 14.0625.
Bingo! As far as transmit stability is concerned, I received a 559 from
Utah during the QSO party with a vertical dipole in the rafters of my
garage before the XYL reminded me that we had tickets to the Berkely Rep
and needed to get ready.
Many thanks Wayne! And many thanks to those QRP-Lers who posted so many
helpful notes. Now about this AGC section of the NC20......
72 Arth W6AGS
=======================================
113. Subject: Re: SST 20 Tunning Range - More!
Date: Sat, 17 Apr 1999 23:14:16 -0700
From: Wayne Burdick
Hi Arth,
Thanks for the note on your success with the SST change I recommended. I'll
be including this information in the next revision of the SST manual, and
will also see if Bob Dyer obtains the same results. We might even change
the resistor value sent with the kit, although having *too* wide of a
tuning range can also be a problem with a small front-panel tuning pot such
as on the SST.
By the way, it was design work I was doing on the K2 that led me to the SST
mod -- there's a similar VCXO circuit in the K2 that serves as the
reference for the PLL.
73,
Wayne
N6KR
>.....Then Wayne Burdick suggested that I reduce the
>value of R5, thus providing a wider voltage swing accross the varactors,
>to 9K from 100K. I though that a bit radical so I first tried reducing
>the resistance to half (50K) with the following results;
>
> MVAM108 14.022 - 14.048
> MV209 14.048 - 14.061
>
>Now that is promising results and motivated me to reduce R5 as Wayne
>recommended. So with a shunt 10K accross the original 100K, the net
>resistance is of R5 is 9K which resulted as follows;
>
> MVAM108 14.022 - 14.050
> MV209 14.041 - 14.0625.
>
>Bingo! As far as transmit stability is concerned, I received a 559 from
>Utah during the QSO party with a vertical dipole in the rafters of my
>garage before the XYL reminded me that we had tickets to the Berkely Rep
>and needed to get ready.
>
>Many thanks Wayne! And many thanks to those QRP-Lers who posted so many
>helpful notes. Now about this AGC section of the NC20......
>
>72 Arth W6AGS
=======================
114. Subject: Re: SST 20 Tuning Range - More!
Date: Mon, 19 Apr 1999 17:42:14 -0700 (MST)
From: Joe Gervais
Howdy Wayne and Folks,
Wayne (N6KR), Designer of my faithful Sierra beast, wrote:
>
> Thanks for the note on your success with the SST change I recommended.
> I'll be including this information in the next revision of the SST
> manual, and will also see if Bob Dyer obtains the same results.
>
> Arth (W6AGS) wrote:
> >
> > .....Then Wayne Burdick suggested that I reduce the value
> > of R5, thus providing a wider voltage swing accross the
> > varactors, to 9K from 100K.
> > [ ... ]
> > MV209 14.041 - 14.0625.
Wayne and Arth, are there any other changes associated
with this mod, or can I simply put that 10K resistor in
parallel with R5 as Arth did and (*possibly*) see a similar
increase in SST tuning range?
Oh heck, may not wait for the answer, since most of you are
even busier than me. *8-) But if/when time allows, please
drop a note here on QRP-L, and I'll follow up with my own
experiment. Just in time for QRPTTF - Wahoo!
Thanks in advance!
Cheers de AB7TT,
-Joe, vole@primenet.com, AZ ScQRPions (Phoenix)
"And that, my Liege, is how we know the Earth
to be banana-shaped." -- Monty Python and the Holy Grail
===================================
115. Subject: SST-20 R5 tuning range mod
Date: Tue, 20 Apr 1999 11:28:18 -0700 (MST)
From: Joe Gervais
Yep, me again.
Per Wayne's idea and Arth's experiments, I added
a parallel 10K resistor to my SST-20's R5 last night,
bringing R5 down to around 9K.
I'd only been getting about 6 KHz of coverage before
(stock kit, no mods - yep, I plan to do extensive
tweaking after QRPTTF :-) ). After dropping down R5
I now have 11 KHz of useable tuning range (14.057-
14.068). Too bad I can't copy RTTY in me head yet. *8-)
Wayne warned me that, after the mod, power may drop
off at the ends of the tuning range, and sure enough
I lose output in the last 1/4-turn of the pot's range.
I'll monkey with that later. But I'm still getting
about double the coverage even with that side-effect.
I'll stick the SST on a power meter tonight and track
the actual output.
Wayne's exact words to me:
"Watch for low power output, though. If this happens (at
either end of the tuning range) you'll want to use a
larger resistor or put a 10uH RF choke in series with it."
Thanks to Wayne and Arth for their help!
Cheers de AB7TT,
-Joe, vole@primenet.com, AZ ScQRPions (Phoenix)
"If it ain't fun, you ain't doin' it right!" -The AZ ScQRPions
======================================
116. Subject: Brief SST Description - KB9LGJ
Date: Mon, 3 May 1999 08:04:14 -0600
From: Tim and Aretta Gordish
I much enjoy my little 20 meter model of the SST. It is a very usable rig,
and a great performer. The 3 watts it puts out is all you will need for
making consistant contacts. The cw filter is narrow so it is easy to use
this rig for contests and pick out signals in a pile up. It is excellent
size- tiny, and the 20 meter version covers both the QRP call frequency and
the FISTS call frequency. Current drain is very low and I built up an
internal batterypack from cordless phone battery packs that will keep the
rig on air for a good two hours- the perfect Spartan Sprint rig! The only
draw back with my rig is the audio volume is low and I use and external
audio amp to fill the shack with sound when no using headphones.
73 de Tim
KB9LGJ
==================================
117. Subject: 10M SST-ALIVE!
Date: Mon, 03 May 1999 17:56:05 -0500
From: mjfitz@uswest.net
Kids-
Just finished building a 10 M SST this weekend. It seems to work,
that is, it puts out about 1.5 W on 12.5 V with a good lookin' wave on
the scope, and the few signals I can hear on 10 M on the TT Delta II are
"hearable" on the SST. I must confess however, I have not made a single
contact with it yet--the band has not been up enough yet for me to
try...
A few of the gory details:
Standard circuit, but used a 16 MHz xtal(Digi-Key X143-ND) and a
frequency doubler (Solid State Design, pg. 44, fig. 24) right out of a
cookbook. Matched the diodes with an ordinary DVM. The doubler output
looks real clean on the scope also--that's why I proceeded with building
the radio...there are about ten parts to this doubler and the text
claims the fundamental is 60 dB down with matched diodes...
Used a bit more of a half-wave output filter (W1FB's Design
Notebook, pg. 103, fig. 4-9, 10 M. componenets).
Did the usual power mods. Build the rig by pad and glue method.
See the IOWA QRP newsletter, spring 99 issue for my 15 M. Pad and Glue
SST "how-to" article available on-line from the club site (below).
Anyone else want to try this and feel they need more details--'mail
me directly.
IA QRP club site:
http://www1.iastate.edu/~drcase/iowaqrp.html#NEWSLETTER
The newsletter IS 5 MB (Word 97) and I understand efforts are
currently underway to format it a bit differently, but it is still an
excellent job by John Burney, NU0V, and contains several interesting
articles besides my stuff...
Just waitin' for ten to open...
Mike KI0AF (of Mad Mike's Basement RF Labs...)
Mo. Valley IA
==================================
118. Subject: KI0AF's 15 Meter SST Newsletter Article
Date: Tue, 4 May 1999 18:54:28 -0500
From: "John Burnley"
Some of you have written me about having trouble getting
the IAQRP Spring Newsletter which has Mike's article
about the 15 Meter SST. It is in Word format and huge
because of my inexperience with PC formats (hey I'm
a mainframe systems programmer and avoid PC's like
the plague hi). Fred Spinner W0FMS has converted the
newsletter to a PDF format and placed it on his website.
My apologies to you all who had trouble in getting the
info. Fred has placed the newsletter at:
http://zeus.ia.net/~spinner/W0FMS/IowaQRP
The Spring 1999 issue contains his article. We will also
have available (soon) more pictures of his SST (which BTW
won the IAQRP building contest) as well as his REGEN
receiver. Both are works of art and I hope Mike considers
entering it into the NorCal REGEN building contest to
be held at Hamcom (for those of you lucky ones who get
to go I am extremely jealous).
72/73, John NU0V
======================
119. Subject: 10m SST comments from N6KR
Date: Wed, 5 May 1999 09:17:04 -0700
From: Wayne Burdick
Hi Mike,
Congratulations on your 10M SST. I haven't designed Wilderness versions of
the SST on 12m and up because the overall RF gain is a bit low on these
bands.
Your doubler approach is interesting. Note, though, that you can also use a
23 or 24MHz range fundamental crystal. They're available from ICM and other
suppliers. You might even consider using a higher I.F. so that a somewhat
lower frequency VXO could be used.
I'm curious what frequency range you chose for your 10m SST. It seems that
CW and QRP operation can be found from 28.0-28.1, with no narrow QRP range
as on the lower bands. This is a bit of a problem for a rig with a small
VXO range.
In any case, I hope to work you K2-to-SST on 10m someday. It's one of my
favorite bands.
73,
Wayne Burdick
N6KR
==============================
120. Subject: 10 M SST - More details
Date: Wed, 05 May 1999 13:38:59 -0500
From: mjfitz@uswest.net
Wayne,
Nice (and surprised!) to hear from you. I have been an admirer of
your work and think you are some kind of electronic genius (the right
kind, that is...).
Yea, I figured the gain would be down thru the mixers at 28 MHz and
had been eyeing the single-transistor RF amp circuits in the
cookbooks...and realizing it might need a switching transistor as a
sidekick to prevent destruction.
I was amazed, however, to hear a couple of quite weak signals on the
Ten Tec that I could also hear on the SST almost as well. I would
"guesstimate" that the signal thru the SST was only 3-5 dB down (just
noticable difference), and I swear it made my jaw literally drop when I
heard it...At this point I proceeded with building a transmiter board
and wiring the thing up.
The freq. doubler circuit I used is a half-wave 1N4148 followed by a
single NPN (metal 2N2222A) -- about ten parts. I used both varactors
(108 & 209) soldered to the backside of a DPDT toggle. The inductor is
27 T on a T50-2, and the thing tunes .043-.063 right now...haven't
really tweaked on it much yet, just got it in the ballpark. I used the
standard 3.93 Digi-Key IF xtals. The gain thru the doubler is unity,
what went in seems to come out, only twice the freq. The text in "Solid
State Design" stated that if you didn't use matched diodes you would
find the fundamental down about 40 dB at the output, and if you matched
them it would be near 60 dB down. I matched them...and cannot see
anything on the scope (Tek TDS 210) but a nice 32 MHz sine...
OK Wayne, thanks for the encouragement. And yes, I hope to work you
SST to K2 on the bands someday, too. I also expect to be able to work
you K2 to K2 one of these days soon because I know that Christmas in May
(or maybe June) is coming when the UPS guy comes strolling up the
sidewalk with a nice box and wants me to sign for it...I dropped my
order in the mail for a K2 on the Friday BEFORE the Monday when you
first started taking regular orders. Hey, tweak that baby all you can
before you sent it to me...I can wait!
Later, 'O Great One
Mike KI0AF
===========================
121. Subject: Re: SST-40 R5 tuning range mod - good details.
Date: Sat, 15 May 1999 21:02:41 +0100
From: Larry Cahoon
After hearing of the R5 mod for the SST-20, I had to try it for the
SST-20. The range on my SST-20 was just fine in my book. But for the
SST-40 with both diodes in the rig I was did not cover 7.038.6 to
7.040.4. Not at all satisfactory. I never got around to doing any of the
other mods to open up the range. Mostly because I did not really want to
change it that much.
The original mod put in a 10K resister in parallel with R5 to bring R5
down to about 9K. I didn't want to open up the range as far as that did
for the SST-20. Also I did not want to get into any problems. So I first
tried replacing R5 with a 47K resister. That did not succeed in covering
the hole. So then I went down to a 33K resister. That solved the problem.
Checked the power out and it is rock solid stable across the entire
range with either diode in the circuit. I think I'm good to go.
The Numbers
100K 7.030.7 - 7.038.6 and 7.040.4 - 7.043.3
47K 7.030.6 - 7.038.8 and 7.039.1 - 7.043.6
33 K 7.030.3 - 7.039.1 and 7.038.5 - 7.043.6
Back to fun on the air, 73/72 de Larry.............WD3P in MD.
====================
122. Subject: 10M SST OPERATES-Comments from KI0F the builder
Date: Sat, 29 May 1999 19:26:54 -0500
From: mjfitz@uswest.net
Brewers--
Have posted a couple of times about the HB 10 M SST under
development...
Worked a few stations with it today in the contest, including CW9A
(Uruguay).
Have added a tuned input/output FET RF amp to front end, one of W1FB's
designs (grounded-gate 2N4416A). Now you must turn DOWN the gain on
strong signals... Didn't have much of an antenna, just a sloper dipole
at 30 ft or so, pointed NW.
Puts out about 1.5 W. on a gelcell and sounds good on the big rig.
Used LDG QRP autotuner and twinlead for feed. Tunes 28.043-.063 at the
moment, with a single VXO xtal (16 MHz + freq. doubler).
Think I'll try and find a few minutes to run it tomorrow--mid-late
afternoon here in IA (CDT). Be around .060 calling CQ QRP...
Mike KI0AF Mo. Valley, IA
===============================
123. Subject: Norcal SST Keying - Wave Shape Info.
Date: Sun, 13 Jun 1999 14:18:57 -0400
From: "Paul Christensen"
For the first time in nearly two years of use, I decided to look at the
keyed wave-shaping on my Norcal SST with an oscilloscope and compare it
against the Norcal 40A and Sierra. A Bird Model 43 together with a Bird
4273 coupler was used as my R.F. sample point. Supply voltage was
maintained at +13.8 VDC. The 40A and Sierra show exceptionally good keying.
However, the SST shows excellent keying on the leading edge, but a hard,
unshaped trailing edge which generates a key click.
In reviewing the SST's schematic, I see little, if any wave-shaping
components between J3, U4, and U5. I realize that the SST was designed as
an exercise to extract the most performance with the fewest components
possible. Has anyone else noted the same keying characteristics? Has
anyone tried inserting a simple wave-shaping circuit to increase the
trailing edge decay time? Thanks!
-Paul, W9AC
===================================
124. Subject: 2Re: QRP SST-20 info - Lots of info from San >> WB9ELB
Date: Mon, 21 Jun 1999 12:49:46 -0700
From: San Rotter
>> San
>> WB9ELB
C:\QRP\Pictures\SST-20X2.bmp;
C:\QRP\Pictures\SST-20-dial-calib.bmp;
C:\QRP\SST-20-VXO-control-adjust.bmp;
C:\QRP\sst-20-10K-pot-tuning.bmp;
Jim -
I used a BNC tee connector with a dummy load on one end and a 10:1 scope
probe to a Optoelectronics Model 2210 frequency counter and made some new
measurements.
14.0 61.9 8
14.0 61.9 10
14.0 61.7 12
14.0 61.5 15
14.0 60.9 20
14.0 59.9 25
14.0 59.1 30
14.0 58.5 35
14.0 57.8 40
14.0 57 45
14.0 56.2 50
14.0 55.4 55
14.0 54.5 60
14.0 53.6 65
14.0 52.6 70
14.0 51.9 75
14.0 51.3 80
14.0 50.6 85
14.0 50.4 90
14.0 50.4 92
There is compresion on both ends. My tone deaf ears worked prety well. I is
hard to tune the transmitter fast w/o smoking the final to a even value. So
I just set the even dial values. Could turn the input voltage to the rig
down to lower the power out and measure on even MHz values sometime.
If you have any trouble recieving any of this email back and I can zip or try
another format.
72,
San
It looks like I will order some Q-dope to attempt to stop the wires from
moving on the toroids and then use a non corrosive clear low loss dielectric
RTV to strain relieve the toroids.
At Motorola they would put the two part RTV in a vacuum for 10 or 15 minutes
to remove all the bubbles. It was shown that migrating bubbles would pull
wire bounds. I have had trouble thermo-cycling coils of all types without
encountering some hysterics. Some coil manufactures I found where terrible
when thermo-cycled.
Q-dope information below:
72,
San
p.s. see below for a couple extra messages:
Q-dope
http://www.qsl.net/~wd8rif/qq.htm
QRP Quarterly
October 1998
"Hard as Nails" as Q-Dope Substitute, W4LJD
Frank Brumbaugh, W4LJD of Salinas, PR. dropped this note -- "Hard as Nails",
a clear liquid plastic intended to overcoat for colored nail polish can
replace Q-dope and is much harder than Q-dope or clear nail polish. Keep the
materials in the refrigerator along with the XYL's nail polish to extend
useful life prevent thickening.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
Central Utah Electronics Supply
735 South State St., Provo, UT 84606
(801) 373-7522 or Fax (801) 373-7736
http://www.itsnet.com/~cues/cues.html
Q-Dope, a polystyrene lacquer
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
Mouser Electronics
Phone: (800) 346-6873
Fax: (817) 483-6899
E-mail: Sales@mouser.com
Mouser Stock#
Description
524-10-3702 G.C. THORSEN INC POLYSTYRENE Q DOPE 10-3702
524-10-3704 G.C. THORSEN INC Q-DOPE-4oz TUBE 10-3704
524-10-4102 G.C. THORSEN INC Q-DOPE THINNER 10-4102
524-10-5002 G.C. THORSEN INC RED-X CORONA DOPE 10-5002
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
http://www.action-electronics.com/gcelect.htm
GC ELECTRONICS 10-5002 153 8.23
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
http://www.allied.avnet.com
Q-Dope Polystyrene, fast-drying. Leaves a clear protective coating.
796-4335. 10-3702. 2 Fl. Oz. Bottle........EACH 5.11
796-4340. 10-3704. 4 Fl. Oz. Bottle........EACH 8.57
Electronic Grade Silicone Sealant/Adhesive One part non-corrosive, neutral
cure electronic grade silicone sealant. Will remain flexible from 60øC to
+200øC (70øF to +390øF). An excellent adhesive for many electrical and
electronic applications where corrosion to metals is a problem. Good
dielectric properties, high surface resistivity and resists electrical
tracking. Meets the requirements of Mil-A-46146a-Type 1; meets the
requirements of FDA status, FDA Regulation #177.260.
796-9845. 19-155. 3 Fl. Oz. (90 ml). Tube
........................................EACH 5.50
Date: Wed, 05 May 1999 16:21:12 -0700
>To: Roger Deutsch 0
>From: San Rotter
>Subject: SST-20 VXO linearization circuit
>X-Attachments: C:\QRP\SST-20-VXO-control-adjust.bmp;
>
>Roger -
>
>I attached a linearization circuit for the SST-20 VXO. There are still
curves in it but it is a lot more linear than without additional parts. I
need to take more points on the curve by making a face plate that has degrees
calibrated on it.
>72,
>San
Don -
You can see the non-linerity close to zero in:
C:\QRP\sst-20-10K-pot-tuning.bmp; Easier to send pictures than describe on
the air. I will have to calibrate the pot more to take more points on the
curve. Here is another message I sent Roger KA9UDA:
72,
San
Roger -
I added a resistor and pot to slightly widen and linearize the tuning range.
new pot series resistor 100K//10K new 10K
/\/\/ |
| ^---- |
tuning pot /\/\/\/\/\/\/\/\/
+ wiper -
clock degrees
Pot Pot Freq
0 6150
9:00 45 5980
12:00 135 5525
3:00 225 5010
270 4900
You can see the old one is not very linear at all. So now that I go to
14.061.5MHz it is not that bad. Real nice radio. You can see that it gets
flat around 270 degrees. But the rest of it looks OK.
Tell how my ascii schematic came out. If it gets messed up I can make a BMP
schematic.
72,
San
=============================
125. Subject: re: audio-out freq. counter for the SST de N6KR
Date: Sat, 17 Jul 1999 10:18:35 -0700
From: Wayne Burdick
Tom, I don't know about the Freq-Mite, but I designed the SST specifically
so that you could put a Wilderness KC-1 memory keyer/audio-out freq.
counter inside the box. The KC1's two buttons and keyer speed control face
up on the top cover. This still leaves room for a 9V battery inside the
case.
Note that the KC1, which I originally designed for the NorCal 40 in 1995,
includes a "search" mode that allows you to use the keyer paddle to specify
a target frequency. You can then turn the VFO knob and you'll be alerted by
the KC1 when you get to the target.
73,
Wayne
N6KR
* * * *
Gang!
Has anyone put a Freq Mite in a SST? If so, let me know how easy it is.
Thinking about ordering one.
72, Tom WB5QYT..."Have spud will travel!"
====================================
126. Subject: SST RIT - RIT SST
While this is a for sale message, Bob says he put an RIT in his SST. Perhaps he can answer questions for interested SST builders. JL
Subject: SST's for sell
Date: Sun, 18 Jul 1999 15:51:31 -0500
From: rbcallahan@juno.com
I have a 40 meter and 20 meter SST for sell. First, on the 40 meter SST
I have installed a switch to switch between two crystals which gives me
about 7.030 to 7.045 or so coverage. Also I installed a air cap on the
front panel for a little RIT control...Also on the 20 meter SST I have
installed a CAP for RIT control that is accessible through a hole I
drilled in the top cover and I installed a switch to switch between both
voltage variable caps supplied with the kit. Both work very well. I am
asking only $65 each. I will sell one or both. First come first served.
I will ship anywhere in US. I assure your satisfaction. I used the 20
meter SST with a homebrew external amp for over a year and love it. I
now have a Sierra and don't use the SST's anymore.
If interested please E-mail me at: rbcallahan@juno.com
Thanks,
Bob Callahan KC5T #1792
==============================
127. Subject: RIT for SST by Bob Callahan KC5T
Date: Wed, 21 Jul 1999 21:32:53 -0500
From: rbcallahan@juno.com
Hello Jim,
I am sending this response to you directly concerning the RIT system in
the SST.
All I did to give me a measure of RIT was to reduce the 270pf cap on the
RX mixer (NE612)by about 15 or so PF and then placed in parallel a fairly
large value air cap in with it (about 40 or so pf). I found in my junk
box one that was also small enough to be mounted on the front. Also,
this cap must be insulated from ground as the 270 pf unit is not
connected to ground directly but through another cap. I don't recall the
cap number but it was the one at a value of 270pf on the RX mixer. By
this I had some measure of RIT through the original setting of the RX
mixer.
That really about it.. If you have any questions just give me a E-mail.
rbcallahan@juno.com
Thanks,
Bob Callahan KC5T
================================
128. Subject: SST howling problem and solution
Date: Fri, 06 Aug 1999 10:04:58 -0400
From: "Ed Lawson"
I have a SST 40 and 20. Both work very well except for one
issue. With the volume up they will often develop an audio
oscillation or howl. I've looked at the list of mods and found
references to fixes, but these seem to be incorporated in the
kits I built. This is not a constant problem, but there is a tendency
to oscillate upon keying with the volume up.
Anyone else encounter this issue and managed to resolve it?
Any construction issues that may be causing it?
Like the rigs, after all I worked a RA3 with the SST20 the first night
it was completed and tested. It was QRP to QRP with Alex running
5 watts.
Ed Lawson
K1VP
Subject: SST Howl Solved
Date: Wed, 11 Aug 1999 15:41:04 -0400
From: elawson@lr.net (Ed Lawson)
Thanks for all the responses to my question on the SST.
Looking at the schematic made me think all the filter caps
that were suggested are now on the board.
Anyway,
being the type who always tries the simplest solutions,
I tried using different headphones as someone suggested
and no longer a problem.
Ed Lawson
===========================
129. Subject: SST: shifting the VXO up; narrow filtering de N6KR
Date: Fri, 20 Aug 1999 12:28:27 -0700
From: Wayne Burdick
Mark wrote:
My SST runs from 7.0245 - 7.0405. How can I get that lil bugger to go up to
7.042 so I can do the AR-QRP net? I can't find any info in the manual about
moving the freq.
Hi Mark,
You can shift the VXO frequency of the SST up in two ways. The easiest way
is to use the supplied MV209 varactor diode at D4 rather than the MVAM108.
However, if you're already using the MV209, try replacing RFC3 with a
slightly smaller choke.
If you end up with a higher end point but a narrower range as a result of
the above, you can regain some range by changing R5 to a smaller value,
perhaps 22 K. (This is experimental, however.)
As for received signal sound: The 38-special has a very wide filter due to
its high I.F. (12 MHz as I recall, and probably something like 1.5 kHz wide
at -3dB). This does sound good -- until you have adjacent-channel QRM. The
SST has a *very* narrow crystal filter (200-400 Hz at -3dB) that is great
for eliminating QRM but is harder on the ears because of the constrained
audio range. This is true of any receiver with a narrow filter; a narrow
band of audio frequencies is more fatiguing to the human ear.
But this is a good tradeoff since the narrower filter also increases
signal-to-noise ratio, making weak signals easier to copy, especially in
the presence of noise. (This is vital on 40m if you're trying to copy
stations in a QRP net about the time that your local power lines start
humming.) To quantify this, the signal-to-noise ratio of a 300 Hz filter
will be about 14 dB better than that of a 1.5 kHz filter, assuming the
information bandwidth is well below 300 Hz (true for most CW signals!). The
math: SN_improvement = 20 log(1500/300) = 13.98 dB.
On the other hand you may have a problem with your SST receiver: it should
never sound "rough" even with the narrower filter.
73,
Wayne
========================
130. Subject: SST -Need cure- Rec Freq. Vs Tx Freq.
Date: Wed, 25 Aug 1999 12:46:54 -0600
From: tom whalen
(Maybe Tom found and answer and will share is you contact him)
Gents!
Need a simple cure for getting the rec freq on the SST to be in more
line with the xmit freq. They have talked about c-10 making it a
variable.Is that the mod for changing the rec freq? Anyone know of a
simple RIT mod for the SST?
Great little rig, but most of the stations I talk too are too low in
freq and it's driving me crazy!!
Worked a couple of stations on 30 meters the other night....One at 100
mw and the other at 300mw...FUN FUN!!
72, and thanks....WB5QYT...."Have spud will travel!"
PS: Just finished my SW-40+.....NEAT RIG! Going to use it RR mobile this
fall and get some pelts!
===================================
131. Subject: SST - rig appeared to change in freq when touched
Date: Tue, 31 Aug 1999 08:40:37 -0500
From:"Mark Hogan"
To:
Thanks to those that gave my input on my SST last week. When I looked
inside there were some extra chokes in line with the original RFC3 which
increased the bandwidth and dropped the split. They were however almost
touching the case. When I had my finger on that side of the case while
tuning, the rig appeared to change in freq. a little as I took my hand away
from the case. I moved these away from the case and this stopped. I then
reduced the value of RFC3 and now have a rig that will go up to 7043.5 this
will let me get on the AR-QRP net with a real QRP rig. Yesterdays fox hunt
announcement did not hurt either, now the rig has the right split for that
also.
I set the power to less then a watt `750 - 900mw, (the MFJ is not too
precise, WM2 is still a dream away). So I'm at least starting to milliwatt.
I need to do some antenna work and put new feedline up in the next few weeks
then I'll cut the power some more.
So there you have it, I'll be on 40 from time to time with my Speed-X bug
(ouch) or for a real challenge the Schurr mini straight key (what a dream)
trying to send at the same slow speed I copy, if ya hear me and feel up to
the challenge of my fist (I'm sure I make anyone else look like a PRO CW Op)
I'll welcome the reply (and those guys on 30 are probably glad to get a
break from me and my 38s).
Mark Hogan / N5OBC
===================
132. Subject: SST sidetone Questions.
Date: Wed, 15 Sep 1999 19:33:49 -0400
From: aa5yx@juno.com
They say that if you only have one clock, you always know the correct
time but if you have two, you are never quite certain which clock is
correct. I now have 2 SSTs - one for 30m and one for 40m (which I just
completed today) and they both have quite different sidetone pitches.
The sidetone in the 40m version is a lot higher than that in the 30m rig,
but according to the troubleshooting guide, I can adjust this tone by
changing C10. My first question is, whether or not I make this
adjustment, do I tune to a station by matching his tone to that of my own
sidetone, even though the sidetone in my 40m SST seems higher than I
think it should be?
And part 2 of the question is, to lower the tone, should C10 be a higher
or lower value? I'm betting it should higher but if anyone knows for
sure, it might save me a step in unsoldering/resoldering!
FWIW, the new rig works great. I just had my 1st QSO with it with W8IMP
in Detroit and then was called by N3AT in PA who gave it a thumbs up.
Thanks and 72,
John Harper AA5YX/2
HW-9, OHR-100A/20m, NC40A, SST/40, SST/30, NC20
YashicaMat 124G Info Page: http://home.att.net/~j..harper
------------------
Subject: Re: SST sidetone
Date: Wed, 15 Sep 1999 20:27:03 -0400
From: "John L. \"Jake\" Carter"
I'm just finishing up a Small Wonder Labs GM-15 -- different rig, different
company. But the rig's manual says that increasing the value of C38 raises
the sidetone pitch (and Tx offset) and decreasing C38 lowers it. Maybe
that's because increasing capacitance increases the frequency, ie the amount
of the offset and the further you get from the zero beat the higher the pitch
-- just guessing on that one.
With regard to tuning the received station, I'd tune so that the received
signal matches my sidetone pitch.
Hope this info helps (I also hope its correct :-) )
72,
Jake -- N4UY
=====================
133. Subject: 10 M SST - Adding and IF Amp
Date: Sun, 26 Sep 1999 00:46:45 -0500
From: mjfitz@uswest.net
Alright!
A ten meter get-together on Sundays sounds good. A few
days ago I put an IF amp in the 10 M SST I have 'brewed.
Stole the design out of the NC20 (thanks Dave!) and put it
just behind the xtal filter. It really pepped it up a
bunch. It also has a grounded-gate 2N4416 RF preamp ahead
of the regular SST receiver, and a MRF-237 final. Puts out
about 1.5 W at 13.8 V.
Now, when you connect an antenna, the band noise is
extremely loud with the volume at max using a sensitive set
of phones.
I told John, NU0V, the editor of the Iowa QRP Journal,
that I would write up a how-to on this radio for the fall
issue. No big secret...just use a 16 MHz xtal followed by a
freq. doubler to get the VXO signal...regular 3.94 MHz 20 M
SST IF xtals and tx mixer xtal. Tunes 28.043-.063 with two
switched varactors.
Yes, I have posted about the rig before, just wanted to
BRAG about the IF amp...
Catch you on ten soon.
Mike N0MF
======================
134. Subject: Re: 15M SST - and 17M
Date: Tue, 28 Sep 1999 21:17:05 -0500
From: mjfitz@uswest.net
Folks,
An SST for 15 M is very easy to homebrew using
pad-and-glue method. Have posted on this topic before...see
link below for article (by KI0AF, a real cool ham) on this
topic.
This guy has homebrew SSTs on 40,30,20,15, and 10
meters. Watch for an upcoming article in the fall issue of
the on-line Iowa QRP Club Journal on building a 10 M SST,
coming soon to a modem near you...
It is also possible to put one on 17 M.
ftp://divis17.ped-gen.uiowa.edu/pub/iaqrp-l/journal/spring1999.pdf
Ah... how's that guy out east put it...melt solder?
Mike N0MF
Mo. Valley IA
(ex-KI0AF)
===========================
135. Subject: 15 Meter SST - Text file from N4SO available.
Date: Tue, 19 Oct 1999 11:10:12 EDT
From: charles k brown
Two versions are in the saved text files.
One changes the parts values from the kit and
another version is a 15 Meter Pad and Glue SST.
sst15m.txt
14 Mhz DX
FO0KOJ 0338Z worked with the NorCal 20 low end of
20 mtrs
Ken Brown N4SO
Mobile, AL/EM50tk
NorCal-20/5 watts/4 ele. beam
--------------
Subject:
Re: 15 Meter SST
Date:
Wed, 20 Oct 1999 01:28:17 EDT
From:
charles k brown
To:
al7fs@pobox.alaska.net
References:
1
Another version is the Mike Fitzgibbon 15 meter Pad and Glue SST
The following is a saved text file.
Contact the source below for details.
From: marion@montana.com
Date: Thu, 2 Jul 1998 11:26:25 -0600 (MDT)
Subject: Move 20mtr SST to 15mtr: component values
DOZENS of requests on moving 20mtr SST to 15mtrs, so here is how I
did it. If you make changes or improvements other than these, please let
me
know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO
VXO
X6 = 25mhz crystals. I used two, one on top, one under
board.
RFC3 = 23t #26 on T37-2(red). This was a critical value
for proper oscillation and range. You may have to adjust
a turn plus or minus, or compress or spread turns to
adjust to desired tuning range.
PA
2.2uh molded choke from base of Q2 to ground.
As above changes were all that was neccessary to put it on 21.050 to
21.070
with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341) for two
watts out. Its also very easy to move to 17mtrs by using same approach.
Good
luck and 72.
Roy AB7CE
sst15m.txt
>From
Subject: Re: 10 M SST///Mike has done the SST 15 using Pad
and Glue method
Ken,
Go to the address below and click on "journal". That will take you
to the club journal on-line. Also, if you click on "ki0af" you can see
more photos of some of my projects, including the 15 M SST (that is my
old call).
I'm sure the fall issue, when it is ready, will be announced to the
list.
Don't get real excited about the 10 M SST yet...I'd still call it
"experimental"...it works, but I think it might be able to use a little
tweaking...that's why I want to let some people see it and give it a
try...maybe someone will come up with some better ideas. I'm just a
hacker...but I have fun...
ftp://divis17.ped-gen.uiowa.edu/pub/iaqrp-l/
If you have any more questions, don't hesitate...
Later,
Mike N0MF
E-mail info mjfitz@uswest.net
ex KI0AF
nnnn
sst15x.txt
=============================
136. Subject: SST 20 mods for 15M @ KJ5TF website
Date: Mon, 25 Oct 1999 16:04:23 -0700 (PDT)
From: Jim Hale
Thanks to Roy, AB7CE for the mods for putting the SST
on 15M.
If anyone needs to see them I made a page you can find
in my links page.
http://www.qsl.net/kj5tf/sst15.html - This site is not active...see
http://www.madisoncounty.net/~kj5tf/sst15.html (I have put the text below.)
This kind of thing takes me back to when I modified a
Ramsey QRP 20 and put it on 21.110mHz when I was a
tech+. It only put out 750mW but I still have the QSL
card on my wall from Palmer Station Antartica.
I didnt have any HF gear, so used my shortwave as a
rcvr.
72/3's de Jim KJ5TF
=====
Ham radio/alt energy http://www.qsl.net/kj5tf/
Milliwatting Editor ARCI QRP Quarterly
Arkansas QRP Club #2
--------------
DOZENS of requests on moving 20mtr SST to 15mtrs, so here is how I
did it. If you make changes or improvements other than these, please let
me know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO VXO
X6 = 25mhz crystals. I used two, one on top, one under board.
RFC3 = 23t #26 on T37-2(red). This was a critical value
for proper oscillation and range. You may have to adjust
a turn plus or minus, or compress or spread turns to
adjust to desired tuning range.
PA
2.2uh molded choke from base of Q2 to ground.
RFC1 to 2.7uh
As above changes were all that was neccessary to put it on 21.050 to
21.070 with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341) for two watts out. Its also very easy to move to 17mtrs by using same approach.
Good luck and 72.
Roy AB7CE
============================
137. Subject: SST-20 Query - RFC5 Mod Information
Date: Fri, 05 Nov 1999 11:17:32 -0800
From: Ed Loranger
Happy Friday to all.
OH! Does anyone know for sure whether the SST-20
should have a 15 uH or 36 uH for RFC-5???
Are there any on-line latest schematics out there? I did
read all the SST-MODS file after a web search, but no
schematic with any updates.
Thanks in advance. ONLY 53 QSO's to go in AR Millenium TEST!
72/Ed we6w
--
-72/Ed WE6W; AR Millennium Q's=> 1943/2000 A-1 OP
http://www.qsl.net/we6w Santa Rosa, CA
QRP-Z#106 AR#112 HI-QRP#64 ARCI#9397 ARS#275 QRP-L#1068 Old NC#2227
Subject: Re: Sprints and Lessons to learn/ SST-20 Query.
Date: Fri, 5 Nov 1999 15:34:15 -0800 (PST)
From: "David D. Meacham"
Ed,
My mod for RFC5 was to change to 6 turns on 20m (see my article "Optimized 20-meter SST" in the Fall 1997 QRPp, page 10...the index on the front
cover has an error in my callsign...it's not W6EMT).
72, Dave, W6EMD
==================================
138. Subject: SST RFC5 34-36 uh 10 turns de AL7FS]
Date: Fri, 05 Nov 1999 17:22:11 -0900
From: Jim Larsen AL7FS
Subject: Re: RFC5 mentioned. de AL7FS
Date: Fri, 05 Nov 1999 12:39:53 -0800
From: Ed Loranger
Thanks to Jim/AL7FS, I'm all set!!!
I pulled RFC-5 and was aghast it was 36 uH on the
AADE/LC-IIB! But now I know that is where it
should be!
Very FB on the help, Jim. Also thanks to anyone else
as well. I'm sure you'd be here too if Jim wasn't so
fast :)
All my best. 72/Ed we6w
Larsen, Jim wrote:
>
> From: http://www.karoo.co.uk/g3ycc/sst1.html
>
> 37. Subject: SST not a toy!/SST mods summarized...
> From: pmeier
> Date: Sun, 29 Jun 97 11:19:11 -0400
>
> I found only one minor mistake and > that was the value given for the choke RFC5 on the schematic. It was listed as 15uh but is closer to about 34uh. Follow the parts list and use 10 turns for RFC5.
--
-72/Ed WE6W; AR Millennium Q's=> 1943/2000 A-1 OP
http://www.qsl.net/we6w Santa Rosa, CA
QRP-Z#106 AR#112 HI-QRP#64 ARCI#9397 ARS#275 QRP-L#1068 Old NC#2227
=================================
139. Subject: XCVR: SST-20m alive; VXO range question; summary of mods used
Date: Thu, 11 Nov 1999 08:52:35 -0800
From: Allan G Taylor
Good morning all.
Flush with success on the NC40A mods, I decided to check out how the
SST-20m was doing before I install the two varactors and related switch.
(I am doing the W6AGS VXO mods)
The mods made are:
Zetex ZR78L08C replacing stock 8V reg
MRF237 replacing 2N3553
RFC5, L2, L3 wound with #22 wire instead of #26
R10 as 120 ohm instead of 180 ohm
R5 as 10K ohm instead of 100K ohm
a 2nd 18.0 MHz crystal in parallel with X6
C6,C9 to 68pF
C7,C8 to 180pF
RFC3 to 4.7uH
(These mods are from various previous posts regarding the SST)
SUCCESS: the little rig came right up and can hear my OmniVI. 20m was
dead last night when I was doing this! C28, XMT mixer output, is VERY
touchy. If a metal screwdriver is used to adjust, power out drops to
ZERO and strange sounds result. A plastic wand works fine, though.
Output power peaked up to 3.7W. I have yet to make any PA LPF component
changes (other than using #22 wire in the toroids). I will likely swap
out the disc caps for SMs and twiddle with L2 with the hopes of getting
~4.5W out. Also RFC5 to 6 turns instead of 8.
The VXO range with the smaller varactor (D4A, MV209) turned out to be
14052-14074 kHz. I like the width of the range but is there a way to
shift it downward a bit? It should give a nice wide range with the
other varactor (D4B, MVAM108). Should I increase or decrease RFC3??
73
Allan Taylor K7GT k7gt@arrl.net http://www.qsl.net/k7gt CM97aq
==============================
140. Subject: Replacement for MV1404, MRF-237 (SST)
Subject: Re: WTB: MV1404, MRF-237
Date: Sun, 12 Dec 1999 19:38:53 +0000
From: Arjen Raateland
Allan wrote:
>
> I got three MRF237s from RF Parts and paid about $6.50 each plus
> shipping/tax.
> Just getting them is a trick. One is in my SST/20, another will go
Look for 2SC1947 as a replacement for the MRF237. It has the normal EBC
pinout like the 2SC799 and 2N3553, so is a lot easier to use than the
MRF237 on PCB's that are laid out for the normal EBC pinout.
--
Arjen Raateland
SAS Support
Finnish Environment Institute, Helsinki
AX.25: OH2ZAZ@OH2RBI.FIN.EU
=============================
141. Subject: re: SST on 9 volts
Date: Fri, 7 Jan 2000 09:32:25 -0800
From: Wayne Burdick
Hi Krause,
National semiconductor has micropower low-dropout regulators -- check their
web site (www.national.com). What would be ideal is a 6- or 7-volt
low-dropout TO-92 regulator; so far I haven't found one. But you can "roll
your own" using one of National's adjustable-voltage low-dropout parts.
You can also use a conventional 6 volt regulator (78L06), which will allow
stable operation down to a battery voltage of 7.4 volts or so. The use of 6
volts will probably cause a small reduction in VXO range. But you could get
the range back by using both supplied varactor diodes with a switch, or
modify the VXO to use two crystals in parallel.
73,
Wayne
N6KR
=====================
142. Subject: SST RIT-Dave Benson's RIT Kit works
Date: Sat, 19 Feb 2000 08:19:22 +0000
From: Roy
To: qrp-l@lehigh.edu
Subject: [63655] SST RIT
Message-ID: <200002200316.UAA04271@mail.montana.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
In case anyone was wondering, Dave Bensons RIT kit works
excellent in a SST. I now have a 15mtr(moved from 20mtrs) from 21.032 to 21.062
coverage with ten turn pot, KC-1 keyer/counter and RIT. Great fun rig. 73 Roy
AB7CE
------------------------------
143. Subject: XCVR: Definitive Tick - SST installation.
Date: Fri, 7 Apr 2000 02:37:11 EDT
From: K7GT@aol.com
To: "Low Power Amateur Radio Discussion"
All the kinks are out, final resistor values are chosen, and it works slick
as well as looks slick. AL7FS and G3YCC please copy for your SST file!
Here's what I did:
I installed a 'bare' Tick1 chip underneath the PCB of the SST, just
toward the front of the rig from the key jack. There is just enough room between the pre-existing solder pads to fit the 8-pin Tick chip there with its legs in the air. I oriented it with pin 1 to the bottom right corner of that spot with the back panel away from the viewer. I used double sided carpet tape but there are more elegant solutions surely.
Connections:
1. Mount a 5V regulator chip across the 100uF power in capacitor, C18. 'In'
to +, Common/Gnd to -. I put a wire insulation scrap on the Common lead to keep it from undesired contact with other metal. The 'Out' pin goes to pin 1 of the
Tick chip. Also needed is a .1 uF from the Out Pin to the Common pin of the VR
chip. Others (notably W9AC in a post a few years ago) have used a pair of LEDs to
get the desired drop from an 8V trace down to the necessary 3-5V for the Tick.
Bootlegging across the existing big electrolytic simplifies installation and
Reduces part count.
2. I mounted a R/S 3-connector jack immediately above the key jack on the back
panel, terminals up (dead bug style all the way!). Ground pin (pin 1) of the
jack to pin 8 of the Tick. Tip (pin 2) of the jack to pin 7 (Dit). Ring (pin 4) to pin 6 (Dah) of the Tick. I used some leftover #26 wire from winding toroids, green for one, red for the other. More colorful and keeps the SSTs weight from escalating (!!)
3. I mounted a 2N2222A (R/S) across the two access pads/holes immediately
adjacent to the SSTs key jack. Collector to K, emitter to G. Then the base
through a 4.7K to pin 5 (Keyline). Also from pin 5 I put a .001 uF to ground (this is C2 on the Tick installation diagram). I used the ground terminal pad on the d.c. coaxial jack adjacent to all of this.
4. Remove pin 2 of the Tick. (Don't use it and it will get in the way
otherwise.
5. Pin 4 to a pushbutton on the front panel above and to the right of the
tuning pot. I chose that spot because it is an easy wire run to the back of the rig along the PCB and I control the P/B for programming the Tick with my left
hand/thumb. My right hand is then on the paddles for the appropriate input from the paddles. The SST (small as it is) is more stable this way when I push the button for programming.
6. From pin 3 of the Tick, form a resistor divider with, first, a 220K (R3
on the Tick installation schematic) and a 27K (R2 on the schematic). R2 goes to ground. I used pin 8 and wrapped R2 around the right hand end of the chip. To the
junction of R2/R3, connect a .1 uF cap and route it carefully (I again used recycled wire insulation) to pin 1 of U3, the LM386N AF amp chip. I chose pin 1 of U3 instead of pad A as it was a shorter run to pin 3 of the Tick and the resistor divider I had constructed there. The schematic called also for a .1 uF from the AF amp end of the first .1 uF cap, to ground, and I originally had one installed from U3 pin 1 to pin 4 gnd). Upon cleaning up the wiring I broke the end lead out of it. The replacement was apparently bad as it caused the audio stage great grief. I removed it, sidetone and keying are fine, so left it out of the final arrangement. In a situation with more RF running around it may be necessary but not in my SST at a roaring 3.5W.
7. I applied appropriate pieces of electrical tape to keep parts from
touching. Parts are fairly compactly arranged around the Tick chip, especially pins 8, 1, and 3. Some tape over the whole business and put the case back on.
Why did I go to so much trouble? Well its like this. I had a Tick1 chip left
Over from a NC20 that had been upgraded to Tick 3. I also wanted to have the
Upstairs of the SST be very clean and not prone to breaking of wires upon fiddling with things in the field. Squeezed between the case bottom and the PCB with tape appropriately applied won't allow these parts to even think of moving.
I give this somewhat lengthy narrative as a guide to other beginning builders
And to show that the Tick can be cleanly installed without the PCB from Embedded
and the associated parts kit. The .1 uF caps came from the NorCal cap kit,
the resistors from NorCal resistor kit, the .001 from R/S (none in cap kit),
the pushbutton is from Mouser (10PA018 for Red) and is a very small and nice
little momentary P/B.
73 and listen for this little rig in August!
K7GT
k7gt@aol.com
===============================
144. SST Modifications compiled by AE5X
http://www.qsl.net/ae5x/mods.html
Increased Tuning Range
Two varactors are included with the SST with instructions to select the one that provides the tuning range you are most interested in. To use them both:
Install a small SPDT switch (RS 275-635) on the front panel.
Clipping the leads as short as possible, solder the hot side of each varactor to the outer terminals of the switch (hotlead of one varactor to one side of the switch, hot lead of the other varactor to the other side).
Using a short wire, connect the center lead of the switch to the hot side of the D4 mounting position on the circuit board. With the D4-side of the board facing you, this will be the left-side hole. The two remaining leads of each varactor are now joined together and connected to the other D4 mounting hole.
Tuning Linearity
Linearity can be a (minor) problem with varactor-tuned rigs. To significantly reduce this in the SST, solder an 18k ohm resistor across the tuning pot between the wiper lead and the +8 volt lead. Experiment with this value as it varies from
band to band and from one type of varactor to another.
Howling
(Terry W0PFR)
My SST 40m version also howled when the audio gain was at maximum. Looking at the application notes on the LM386 audio chip that is in the SST, I noticed that there is a comment that if the chip oscillates then an optional DC filter can be installed to prevent the oscillation. The filter is only a resistor and a by-pass capacitor placed in the lead supplying power to the chip. I have installed the modification and it seems to work. The changes can be done on the etched side of the pc board.
1. cut the trace going to pin 6 of U3
2. solder a 100 ohm 1/4 watt resistor from pin 6 of U3 to the contact next to pin 1 of U3 .
3. solder a .1mf disc cap from pin 6 of U3 to pin 4 of U3
Sidetone Level
(Wayne N6KR)
There are two ways to reduce the sidetone volume in the SST - reduce the AF Gain or, as recommended by the rigs' designer, Wayne N6KR:
Usually there is a good balance between the incoming signals and the sidetone in the SST. But you're right--if you have to turn it way up, the sidetone gets loud.
The only sure-fire way to mute the sidetone to a lower level is to insert a low pinch-off JFET like a J201 into each leg of the audio connection from the product detector to the audio amp. This is how I do it in the NC40A. Actually you can probably find other JFETs that will work; J310s are mostly low pinch-off,
too. MPF102s will work if you hand-select them for low pinch-off.
The source leads go to the '602 and the drains to the original capacitors that go to the '386. Tie the gates together and add a 1 to 10M pull-up resistor from the gates to one of the source leads. Next, connect a diode from the gates to the key input. Test the circuit thus far by keying the rig: you should hear ZERO sidetone at this point, because pulling the gates low cuts off the JFETS, making them look like an extremely high resistance. If you hear a click on keydown, put a resistor (start with 1K) in series with the gate diode. If you hear a click on key-up, add a capacitor from gates to ground; start with about 0.1uF and see if you can go smaller. (It will depend on the pull-up resistor; 10M and .047 work well in most cases.)
Once this much is working, you can add a resistor *across* one of the JFETs (source to drain) to allow some sidetone to sneak through--as much or As little as you want. It will take a large resistor, something like 1 to 15M in my experience.
20 Meter SST to 15 Meters
(Roy AB7CE)
Dozens of requests on moving 20mtr SST to 15mtrs, so here is how I did it. If you make changes or improvements other than these, please let me know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook:
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO VXO
X6 = 25mhz crystals. I used two, one on top, one under board.
RFC3 = 23t #26 on T37-2(red). This was a critical value for proper oscillation and range. You may have to adjust a turn plus or minus, or compress or spread turns to adjust to desired tuning range.
RCV MIXER
RFC1 to 2.7uh(or close to it). Improves match to Filter and recieve.
PA
2.2uh molded choke from base of Q2 to ground.
As above changes were all that was neccessary to put it on 21.050 to 21.070 with the MVAM108. Output was 1 watt,so I put in MRF237(ECG341) for two watts out. Its also very easy to move to 17mtrs by using same approach.
Addendum:
I put two crystals in both of my SST's to extend vxo range. One is 20mtrs and the other is one I moved to 15mtrs. With the MVAM108 varactors I was able to get about 20khz range. I was experimenting with different varactors I had on
hand. Was not getting much difference. Then I tried a MV1404. WOW! The 20mtr version is covering from 14.013 to 14.064. The 15mtr version is covering from 21.039 to 21.073. Scope shows solid waveforms across oscillator ranges. I don't know where to get them. They don't show up in my cross reference, so I don't even
know what they are rated as. Mine were in a envelope of a dozen, that was in one of Dans Small Parts 20lbs of parts for $10.00. They are not listed on his current page. If any one knows what they are rated or where to get them, they might inform the rest of the list.
Miscellaneous
(John AE5X)
The TiCK keyer in my SST is mounted on the rear panel above the key jack. The new jack (required for paddles) is mounted above the RF Gain control on the rear panel and the pushbutton switch is mounted above the antenna (BNC)
connector. Using a Xerox machine, I reduced the the size of the TiCK's program menu and laminated it to the top cover of my SST.
Also taped to the top panel is a tiny chart showing my operating frequency at 9 O'clock, 12 O'clock and 3 O'clock positions for both positions of the SPDT varactor switch.
To make tuning easier, a larger tuning knob is helpful. I use a RS 274-402.
===================================
145. Subject: Moving the SST20 Frequency range - RFC3
Date: Fri, 10 Nov 2000 20:33:52 -0600
From: mjfitz@uswest.net
To: Jim Larsen AL7FS
You want to change the one in the VXO, RFC3. It is 5.6 uH in the 20 M SST. In
the homebrew 20 M SST I used a T50-2 core and about 27-28 (hard to count now...)
turns of #26. Don't go any smaller in wire size because it won't support the
core. If you spread out the turns on a core it decreases the inductance, so
before you remove a turn be sure and spread the turns out around 80% or so of the
core. Doesn't matter which way it is wound. To increase the inductance, of
course, just bunch the turns up more tightly. As long as you don't cook the
traces off the PCB you can play around with this and you probably will get it set
where you want it if you keep at it.
When you reduce the inductance of this choke, it will raise the top end of
the tuning range, and it will also raise the bottom end at the same time. If you
go too far and make the inductance too little it will not oscillate or it will get unstable and maybe only run in part of the range. It won't be hard to tell when that happens.
If you can get some 5.6 uH chokes locally you can try a few of them and find
an actual value slightly lower that the one that is now installed. The meter you
have will help a lot in figuring all this out...go for it!
If you have any more questions just ask Jim.
MF
Jim Larsen AL7FS wrote:
> I might do that. I have the AADE L/C meter so if I can figure out which
> inductor you mean, I can take it out, measure it, and start trying lower
> values.
>
> Any tips on how to wind one? I bought the NorCal torroid set so I have
> cores if I need one.
=======================================
146. Subject: Moving the SST VXO frequency range
Date: Wed, 24 Jan 2001 22:12:10 -0600
From: mjfitz@uswest.net
To: Jim Larsen
Jim,
If you want to move your rig up in frequency you need to
change the choke in the VXO...it needs to have less
inductance. It is a 5.6 uH choke. What you need to do is
find another 5.6 uH choke that has slightly less inductance
than the one in there now... the chokes are available from
Mouser and the stock number is in your SST manual...it's
"43LR566". Order about ten or so and start trying them...
if you have one of those AADE cap/inductance meters it is a
little easier, or some kind of inductance meter you can
borrow. If you have an extra $100 sometime and plan on
doing a little 'brewing they are simply fabulous to have for
the money...
If there is room (had an SST but no longer) you can also
use a toroid, even if you have to mount it slightly higher
off the board. The homebrew 20 M SST here looks to have 27
turns (hard for me to count) on a T50-2 core. I can send
you some cores if you like? ...just got a LARGE sack of
these cores at the hamfest so I have plenty (1000 pcs !!).
They cost me 2.5 cents each... I can spare a few, or even
more than a few... will also include some #26 wire?
What you should do is wind one up with about 29 turns
and try it... if you spread out the winding it reduces the
inductance and if you compress, increase...so...try starting
at 29 turns and then reduce the count just one turn and try
again. The difference of just one less turn can be quite
dramatic in a VXO, so just go for one less turn at a time,
and you can manipulate the winding's spacing a bit to fine
tune it...don't wind the wire real tight on the core so it
is easy to move.
The cores can be installed more easily if the mounting
holes in the board are clear, so after you get the leads out
take some solder wick and press it against the holes and
turn the board upside down while holding the wick to the
board with the iron tip. As soon as it heats thru gravity
will run the molten solder out. You need a fairly hot iron
for this, but not a large one...20-35 W will be just fine.
After you do this a couple of times it is quite easy...and
works well. Sometimes it helps to add just a smidgen of
solder to give you a spot of solder to heat, if the solder
does not come all the way to the top (bottom) of the hole
where your tip can heat it.
If you want to add the other varactor it is easy to
do... Go to RS and get a micro-sized DPDT toggle switch and
mount both varactors on the switch with leads just long
enough to reach the terminals...put the MVAM108 across the
top two terminals and the MV209 across the bottom two.
Install the diodes in the same orientation as on the
board...that is, be sure to observe the polarity. Mount the
switch right above the holes for the varactor in the board
and in line with the other controls, of course. Run a
couple of short "naked" wires down to the holes, making sure
that the orientation is the same.
This is pretty easy to do and I KNOW you can do
it...just give it a try. If you mess up the traces on the
board (highly unlikely) they are easy to fix by laying a
length of small bare over where the trace is broken or
missing and solder it in.
Take care and let me know what you think,
your pal,
MF
=================================
147. Subject: Re: RIT for SST?
Date: Thu, 29 Mar 2001 17:03:15 -0700
From: Roy
At 05:18 PM 3/29/01 -0500, John Harper AE5X wrote:
>Hello reflectees,
>
>Has anyone added an RIT circuit to their SST. I'd appreciate any details
>from anyone who has.
It was an easy matter to put one of Dave Bensons RIT kits in my SST's .
I have also 10 turn pots with extended VFOs in same. Roy AB7CE
------------------------------
148. Subject: Scratch built sst-40
Date: Thu, 05 Apr 2001 20:51:39 -0400
From: neil
Greetings-
Well I sure did have fun building from scratch, the SST-40. I get about
13 khz with the vxo and have the output set at just under 1 watt. It
really is a great design. I may have to build another for a differant
band. Hit on the link to see some pictures of my version of the SST-40.
http://www.angelfire.com/pe2/hott/sst.html
72-
Neil wa4chq
149. Subject: Re: SST Sidetone too LOUD!
Date: Sat, 05 May 2001 05:47:17 -0400
From: ae5x@netscape.net (John Harper AE5X)
n0tu@webaccess.net wrote:
>
> I just finished building a HB 20m SST and can't seem to tame the sidetone.
> Any tips or mods or suggestions?? TIA ~Steve/n0tu~
>
Steve,
I have the sidetone mod from the rigs' designer (N6KR) on my page at:
http://www.qsl.net/ae5x/mods.html
73,
--
John Harper AE5X
Outdoor QRP: http://www.qsl.net/ae5x
150. Subject: Scratch SST & L/C Pill Bottle
Date: Sat, 5 May 2001 13:14:01 -0600
From: "Steve/n0tu"
Here's a pic of my final 'ugly-hattin' Scratch 20m SST awaiting packaging.
It works!!!! Rolling ur own is sure fun! And it's not hard!
http://www.webaccess.net/~s&p/images/SSST.jpg
This little pill bottle LC tuner I've been experimenting with offers some
fun possibilities. The L and C (mini variable cap in the lid) are brought
out to the binding post so you can mess w/any possible ant combo you might
run into. I haven't had a chance to run it through a field test yet other
than a loading a 50' piece wire around the room.
http://www.webaccess.net/~s&p/images/lc%20meds.jpg
Cheers ~Steve/n0tu~
151. Subject: Scratch SST's case.
Date: Sat, 12 May 2001 08:42:38 -0600
From: "Steve/n0tu"
Hi gang,
I got my scratch-built SST in it's case.
http://www.webaccess.net/~s&p/images/SSST.jpg
http://www.webaccess.net/~s&p/images/SSSTtop.jpg
Next is putting a keyer and the Unicounter in the lid(or maybe an AFA
instead?). This guy is turning out to be kinda trail friendly in terms of
weight. Although I'll have to be careful not to drop it on a rock! But I
bought a spare case. There were $2.50 at a local Hobby Lobby.
Yeah, bands kinda weird. Heard a loud JA this morn' on 30m ...only signal on
the band. Just worked a K5 in Texas who was running 80w but he quickly faded
into the noise! Must be the Dayton syndrome!
Back to building. Steve/n0tu
152. Subject: Re: Scratch SST's Layout
Date: Sat, 12 May 2001 11:57:15 -0600
From: "Steve/n0tu"
To: "Jim Larsen AL7FS"
Hi Jim,
I had the schematic from my earlier purchased of the WR SST. As far as
layout I just started with a 4" sq piece of PCB (cuz it fit in my plastic
box) and started building. Jerry/W0PWE sent me his layout which is even
nicer. We built them at the same time checking each others progress. I also
sent a box-O-parts to my new ham bro-in-law who built one. We've QSOed each
other w/'em! FUN Stuff!
If you can receive attachments I'll FWD his along. I did sorta use Jerry"s
general layout but then did my own thing which is the fun of it all. And the
SST is a pretty simple design to debug!! But really works better than the SW
series in my way of thinking! Nice sharp filter and sidetone is pleasant!
Cheeers Steve
You've probably seen these two:
http://www.webaccess.net/~s&p/images/SSSTtop.jpg
http://www.webaccess.net/~s&p/images/sstrx.jpg
153. Subject: Re: Scratch SST's Layout
Date: Sun, 13 May 2001 08:39:25 -0800
From: Jim Larsen AL7FS
To: Steve/n0tu
Yes, I will send a note to Jerry (W0PWE). Thank you.
Jim
Steve/n0tu wrote:
>
> Jim,
>
> Here's the layout and his finished unit. (nice! huh?)
>
> Sounds like you guys had a blast.
>
> Sri I thought I still had a photo of his finished PC layout. Can't find it.
* Maybe ask Jerry for it?
154. Subject: RE: SST Enclosure Question
Date: Sun, 13 May 2001 17:31:43 -0500
From: "Aartec"
To: "Jim Larsen AL7FS"
Hi Jim,
Yea, you should build one. You will have a great time building and operating
it. I really like the fact that it has an AGC. For only three components,
the AGC really makes operation nice. The fellow who sent you the .jpg
probably took the low resolution image from my web page. I will send you a
layout of higher resolution and along with it some notes that may be useful
in interpreting it.
The enclosure is a story in itself. A couple of years ago, while I was still
fairly inactive in ham radio and QRP, I spotted some electronics equipment
in a dumpster on a Friday afternoon. I knew it was pretty good stuff but had
trouble swallowing my pride enough to dive in. I drove by there several
times over the weekend and finally at about 7am on a Sunday morning I
decided to pull up next to it and load up. That stop yielded, among other
things, the enclosure for my SST. It is made by Schroff and is intended to
be a module in a 19 inch rack assembly. The body is extruded aluminum
roughly 11 inches long. I cut it in half and then did some major hacking on
the aluminum panel to make it look more like a QRP rig and less like a
sub-panel that belongs to something else. It has it's problems but I was
determined to make use of my freebee treasures. And now you know that I am
really just a dumpster diving scrounge!
You are correct on the board size. It is 4.95 inches square to be exact.
That size was determined by the card guides inside my enclosure. Concerning
the RIT, I have not experimented any further with that. Initially I tried
several circuits but they all had problems. A ham from CO sent me a copy of
the RIT circuit used in the MS15 and I think the approached used in that
circuit has merit. It uses a summing amplifier to add the main tuning pot
signal and the RIT signal. BTW, I am working on the AFA again and it is
pretty close to finished now.
Thanks for your kind words. I am not really doing much original design work
here but I am sure having fun. The hobby is great for me right now. I just
can't say enough good things about the QRP movement and the people involved
in it. I hope you decide to build an SST. I will be happy to help in any way
I can.
72
Jerry
W0PWE
155. Subject: SST layout
Date: Sun, 13 May 2001 17:46:37 -0500
From: "Aartec"
To: "Jim Larsen AL7FS"
Jim,
Another fellow asked me for the artwork. Here is what I sent him. Let me
know if you have any questions. The PCB layout software wasn't intended for
Manhattan layouts so there are some problems. Still better than paper and
pencil I think.
73
Jerry
----------------------------------------------------------------------------
----------------------------------------------------------------
I will attach the jpg file to this e-mail. Following are some things that
are important to know about the artwork:
1. I did the layout for my own use and although I did revise it when I
finished building my SST, I can't guarantee that it is mistake free. I am
more than happy to share it but use it at your own risk. You will definitely
need to check the connections against the schematic as you go. If you find
mistakes as you build it please let me know so that I can someday update the
drawing.
2. One problem with the layout is that when it prints to a file the pad
master layer makes all the pads the same color. In the original CAD file I
used a different color for the ground connections. Unfortunately you can't
see that in the .jpg file.
3. The size of the components, mostly the capacitors, were just a guess when
I laid it out. In most cases I tried to be conservative and used larger
component sizes than actual, in a few cases spacing is a little tight.
4. The copyright notice is not there to scare anyone away. I would be
totally amazed if someone could take this thing and actually make money with
it. I am very pleased that others may be able to make use of it. If someone
does use this artwork and writes a related article, it would be nice if they
would mention my contribution.
5. Most important: Send me pictures of your project or e-mail me to let me
know how it is going. It is fun to see what people are building!
I hope this layout is of help to you. Let me know if you have any trouble
with the .jpg file. If you do use the layout as a guide I could send you a
good resolution photo of the board as built. Hope to work you someday SST
to SST.
73
Jerry
W0PWE
156. Subject: TiCK in SST--here's what I did
Date: Sat, 19 May 2001 19:55:54 -0600
From: "David Ek"
Gang,
A while back I posted to the group asking about resistor and capacitor
values for building my TiCK into my new SST. Specifically, I wanted to feed
the audio from the TiCK output into the SST audio chain. No one responded.
So, I figured it out for myself. (Yeah, big whoop...)
But a few others were interested in the answer, so here it is. If you have a
TiCK PC board, this might make some sense. If not, maybe it won't.
Pin 3 of the TiCK chip is the audio output (for sidetone and commands). On
the TiCK board, resistors R2 and R3 form a voltage divider to reduce the
audio signal to a small level. I used 1K for R2 and 100K for R3, effectively
reducing the voltage level by a factor of 100. C4 is a DC filter capacitor.
I used a 0.1uF cap for C4. I omitted C5 (if I included it, funny things
happened in the detector stage of the SST--the detector LED would light,
even if the TiCK had no power).
Okay, for those of you without TiCK boards, here's a description. One end of
R3 is connected to pin 3 of the TiCK. The other end is connected to R2. The
other end of R2 goes to ground (so R2 and R3 are in series between pin 3 and
ground). One end of C4 connects to the same point where R2 and R3 are
connected, and the other end of C4 is connected at "A" on the SST board.
You might need to experiment a bit with the values of R2 and R3 to get what
you want.
Hope this is useful to one or two of you.
73 de Dave AB0GO
157. Subject: SST success. changed out RFC3 to move range
Date: Tue, 12 Jun 2001 17:38:30 -0800
From: Jim Larsen AL7FS
Hi Mike,
I finally took your advice and changed out RFC3 on my 20 meter SST.
Once I had the part out I measured it with my AADE meter and it was 6.33
uH (spec is 5.6 uH). With that my range was 14.045 to 14.058.1.
I replaced it with a 5.56 uH inductor and now my range is 14.052.8 to
14.062.1. This range is just fine with me.
MDS checked out at about -139 dBm.
I haven't checked output since the first time but it does something over
1 watt with a AA battery pack. I will probably just leave it as is.
I may run the next Spartan Sprint with the SST without the case. The
rig, key, battery and cable, and ear buds weighs 11.75 ounces or .73
pounds. I will miss the extra 6 dB of signal however but it still
should be fun.
Thanks again for the help, Mike. Enjoy the convention this weekend...it
sounds even better than last year, if that is possible. :-)
73, Jim
--
Jim Larsen, AL7FS, Anchorage, Alaska
(BP51cc) - 61.101 North, 149.824 West
mailto:al7fs@arrl.net - http://www.qsl.net/al7fs/
158 Subject: AL7FS SST output is low - Need help
Date: Thu, 14 Jun 2001 15:18:15 -0800
From: Jim Larsen AL7FS
To: qrpbob@datatamers.com
Hi Bob,
I need some help on this SST20 of mine. It works fine as far as it
goes. The MDS is about -139 dBm which is not bad. :-) Sidetone is just
fine. Volume while not ear breaking is ok. Has a nice pleasant mellow
sound for my ear. Tuning range now ok. IF Bandwidth feels ok to me.
However, I can only get 690 mW out. Made a contact with ZL1 with it two
days ago so it works at least that far.
Here is what I have done, observed and measured. Perhaps you can point
me in the right direction.
1. I changed RFC3 from the 6.33 uH provided (as measured on AADE L/C
Meter III) to a 5.56 uH. That set the frequency up just fine at about
14.052 to 14.062.
2. I had two versions of the SST manual. One said 8T and one said
10T. The more current manual said 8T. Several emails said to use the
10T for RFC5 to get something close to 35 uH. The schematic states 15
uH. I had originally installed it with 8T. I changed it to 10T with
#26 wire and a measured value of 38.6 uH. 9T was 31 uH and the original
#28 8T was 25 uH.
This made no difference in the output power. Stayed at 690 mW.
3. I changed R10 to 120 ohms. I think it was 180 ohms but may have
been 150 ohms.
This made no difference in the output power. Stayed at 690 mW.
5. I decided to check the voltages.
I set up the PS and it was reading 13.9 Volts DC on the Fluke DMM.
I will only report the voltages that were off by more than 10% or just
plain wrong.
SPEC Measured
RCV TX RX TX
U4-5 >8.0 6.8 7.97 7.97 no change but should
U4-8 >8.0 8.0 8.00 6.57 big change but should not
U5-6 >8.0 7.2 13.9 7.51 RX Voltage way high
U5-7 13.8 13.7 8.94 7.14 Way off low
BTW, my schematic does not show where U4-5 goes to? Can you mail me a
schematic that shows that connection?
extra info:
I check all TX and RX for U4, U5, U6, Q1, Q2. All measurements except
the above were within expected levels. Voltage regulator was output of
7.97 Volts DC.
I would be happy with 1.5 to 2.0 watts but would prefer not to be down
at 690 mW as that is just too tough from up here in Alaska.
Where should I go next? I have a spare NE602 but not the LT1252. I have
not tried changing out any chips yet. They are in sockets.
Thank you in advance for your help. I sure wish I knew theory and
troubleshooting. I am trying to go as far as I can each time.
73, Jim
--
Jim Larsen, AL7FS, Anchorage, Alaska
(BP51cc) - 61.101 North, 149.824 West
159. Subject: Re: AL7FS SST output is low - Need help
Date: Thu, 14 Jun 2001 17:31:06 -0700
From: bob dyer
To: Jim Larsen AL7FS
Hello Jim,
Your measurements of dc voltage clearly indicate the problem is a u5-7,
if your power supply is not sagging, either u5 is bad or you have a some
unknown resistance in the v+ line. ( possible short?)
Did it ever put out 2 watts? What is the final transistor. If 2sc799 is maybe
wimping out at 14 mhz, but I would expect at least a watt. Does c28 bring the
power up beyond 690mw?
Bob
160. Subject: Re: AL7FS SST output is low - Need help
Date: Fri, 15 Jun 2001 01:06:16 -0500
From: mjfitz@uswest.net
Jim...I would be looking for the problem with the transmitter voltages...that would explain your low output...somewhere there is a bad or wrong
part or a bad connection in the voltage line in the transmitter section. Get your schematic and go thru all the transmitter parts and make
sure they are the right one in the right spot, diodes with correct orientation, etc. If you measured each resistor as you put it in...you don't have that worry...if you didn't...make sure they are correct. It's very easy to miss-ID those little color bands...I know!! Could you have blown the 1252 somehow...momentary short with something while it was powered up...? Usually the ICs are checked and tested and unless something nasty happens to it... DigiKey sells those...not Mouser.
Take out the LT1252 and see if the voltages are still screwy on the pins, that way you know if the IC is causing the low voltage or if the voltage line itself has a problem. Do that with the TX mixer/osc. also if needed. You can't screw anything up by putting it into transmit if an IC is missing
mf
161. Subject: Re: AL7FS SST output is low - Need help
Date: Sat, 16 Jun 2001 07:52:06 -0700
From: bob dyer
To: Jim Larsen AL7FS
Hello Jim,
I am leaving for vacation today, but will have a knob and ic mailed to you.
Are you sure it is not a problem in the final or output filter? Double check
# of turns on all tx toroids. You will lose 0.25 watt per turn on the output
filter.
Bob
162. Subject: SST Low Output Power
Date: Mon, 18 Jun 2001 18:33:41 -0500
From: Aartec
To: Jim Larsen AL7FS
Jim,
Did you build this SST from a kit? I know you were considering building one
from scratch. Here are my thoughts:
1. The voltage at U5-7 may be at the root of the problem. This is basically
connected to the supply voltage so I am wondering about the following:
A. Could your power supply be sagging? What is the voltage right at the rig
input during transmit?
B. How much current does the rig draw on transmit?
C. Is the power switch S1 OK? Is the voltage into and out of it about the
same?
D. Could U5-7 and also RFC6 be connected to the 8V supply instead of the 12V
supply?
E. As Mike suggested, maybe the LT1252 is drawing too much current. He
suggested you pull it out and see how the voltage on Pin 7 looks. If the
power supply is OK that is the next thing I would try.
F. The only other thing that might load the supply on transmit is the final.
You could try lifting one end of RFC5 and then check U5-7 on transmit. The
final seems to be doing the job though. With 7.14 volts on it power out
should be (7.14 X 7.14)/2(50) = 510mw.
2. The voltage at U4-8 being low on transmit would also indicate that either
the 13.8V input is getting pulled down or something is seriously loading the
U6 output on transmit. Check this voltage again after you have pulled the
LT1252. It may be OK then. If not pull U4 per Mike's suggestion. If the
voltage returns to normal then look that circuit over very carefully and if
you don't find any problems put your spare 602 in there.
3. You asked about U4-5. It is not connected on U4. Pins 5 and 6 are both
used for balanced output and only one is used for single ended output. I am
not sure what to expect for a DC voltage on this pin.
Good luck. Let us know what your investigations turn up.
72
Jerry
W0PWE
163. Subject: WOCH 20 meter SST transceiver + Builder's notes, howl, Tick
Date: Mon, 13 Aug 2001 17:32:07 -0800
Wilderness Radio SST
WOCH 20 meter SST transceiver, modified with a TICK keyer (Tick-1)
http://www.w0ch.com/sst/sst.htm (Valid as of September 2004)
Click on any picture for a larger image
The Wilderness Radio SST (Simple Superhet Transceiver) is a compact
single band CW transceiver that covers a portion of either the 40, 30 or 20 meter bands. It is a very easy project to build because of it's simplicity. There are fewer parts in the SST than most other kits, however despite its simplicity, it is an excellent on-the-air performer.
The kit uses standard through hole parts (no surface mount parts) and a
high quality PC board. It includes a predrilled but unpainted aluminum
case.
The SST receiver is a single conversion superheterodyne with a three
pole crystal filter. The local oscillator uses a varactor tuned VXO
(Variable Crystal Oscillator) instead of a VFO, which results in
excellent stability in varying temperatures. The transmitter produces
between 1 and 2 watts of RF output, depending on supply voltage.
Because the SST uses a VXO for the tuning, only a portion of the band
can be covered. Wilderness supplies two tuning varactors with the kit and the builder can choose either (or both) varactors to customize band coverage desired. Some builders add switches to their rigs to select the varactors for maximum
band coverage.
Note that the VXO crystals supplied are off the shelf computer crystals
and you may possibly not get coverage of all of the QRP portion of the
band. In the WOCH 20 meter SST, only the smaller value varactor was used
and this resulted in a band coverage of 14054.5 to 14062.5 kHz. The
larger value varactor would tune lower in the band, however it reduced
the coverage in the QRP portion of the band above 14060.
The tuning control is a single turn potentiometer, however this works
fairly well with the limited tuning range. The builder must provide the
dial calibration. Because of the simple design, there is no provision
for RIT (Receive Incremental Tuning).
The WOCH 20 meter SST in the photographs has been modified with the
addition of an internal TICK keyer. The keyer was constructed "Manhattan" style on a small piece of PC board material and mounted on the rear of the chassis above the antenna and power jacks. The red push button seen on the front panel is the TICK keyer programming button. This single button is used to set the keyer speed and mode.
Inside the SST, showing the TICK keyer modification
The SST uses very little power. The receive current drain (including
TICK keyer) on the WOCH rig is 20.3 mA. The key down current is 325 mA
for 2 watts of RF output power from a 13.5 volt DC
supply. When powered by 8 AA batteries, the RF output is about 1.5
watts.
The SST is probably one of the smallest transceivers available. The case
measures 3.4 inches wide, 1.5 inches high by 3.75 inches deep. The rig
as shown weighs 7.5 ounces.
Because of the very stable VXO, low power consumption and small size,
the SST is a favorite among backpackers and mountain climbers. I use the
SST in the photograph for a trail friendly package
where the entire station, including battery, antenna and carrying case,
weighs less than 2 pounds.
Rear view showing the added paddle jack above the standard key jack
The SST is available as a kit from Wilderness Radio (URL below). There
are four frequency ranges available The approximate frequency range of each model using the two provided tuning varactors is shown below:
BAND
Using MVAM108
Using MV209
40 Meters
7.030 - 7.040
7.035 - 7.045
40 Meters Novice
7.105 - 7.115
7.110 - 7.120
30 Meters
10.095 - 10.110
10.105 - 10.120
20 Meters
14.040 - 14.055
14.050 - 14.060
Builder's Notes:
I discovered that the LM386 audio chip would howl loudly when 300 Ohm
headphones were used on the rig. The howling was less pronounced with a 20 Ohm headset. The howling was stopped by adding a 10 Ohm resistor across the 1 K volume control (from "hot" to ground).
A further increase of AF amp stability was gained by adding a .001 uFd
RF bypass capacitor across the headphone jack.
The 20 meter tuning range using the MV209 varactor was 14054.5 to
14062.5 kHz, slightly higher than the range specified in the instruction book. Since there is QRP activity above 14062.5 during contests, an additional couple of KHz range would be desirable.
TICK Keyer Modification:
The TICK keyer uses the TICK-1 chip. It is powered from the 12 power
line through a 78L05 regulator chip. A 20K trim pot is used as a sidetone level control with the wiper connected directly to the headphone jack. The paddle jack was mounted immediately above the straight key jack. The programming push
button was installed on the front panel above the headphone jack.
Links: http://www.fix.net/~jparker/wild.html
The ARS QRP Lab Reviews the Wilderness Radio SST Transceiver
http://69.5.23.180/ars/pages/back_issues/1999_text/1299_text/sst_review.html
164. Subject: SST question, C28, output of U4
Date: Thu, 23 Aug 2001 09:29:17 -0400
From: Upton, Shawn
Reply-To: SUpton@ALLEGROMICRO.com
To: Low Power Amateur Radio Discussion
C28, is that known to be "touchy"? I sat down and did the alignment last
night. First, I got the reciever working good--I was able to inject in a
-120dBm signal and hear it (really faintly, but there). But, using a
spectrum analyzer, I was getting about -30dBm output, with spurs. Time to
go over to the scope.
Looking at the output of U4, I was getting a mess on key down--nasty looking
signal--must be oscillating (in a bad way, not the good way!). I redid all
the solder joints on the tank circuit there, still had a mess. I finally
put a screwdriver to C28 and finally got a good signal at one point--but I
had to make a plastic screwdriver to do the final adjustment. I finally got
a good signal, and finally adusted the pot for about a watt output (I didn't
feel like pushing any more out, for future battery use).
So, it works--but my question is--is this normal? I'd expect the output of
U4 to rise and fall in regards to the tank adjustment, not go into and out
of oscillation.
Also, am I looking at the output circuit (of U4) correctly? Is this a tank
circuit, or filter? I know that a tank circuit works as a filter, but...
Given the light coupling--5pF--I thought it was a tank circuit, not a filter
with controlled input/output impedances.
Shawn Upton, KB1CKT
165. Subject: motorboating is sst 20
Date: Sun, 20 Oct 2002 19:42:07 -0400
From: John F. Karpus R.Ph.
Gerrr. Anybody have any mods for a motorboating sst. It only happens
in a certain range on the af pot. i.e. from about 40% to 95% full
volume, at the low or highest end the audio is fine. Boy that sidetone
can get LOUD. - John Kc2fpr
166. Subject: motorboating is sst 20
Date: Mon, 21 Oct 2002 19:26:34 -0400
From: Fran Flynn
Yep, bypass pin 7 of the LM386 to ground with a small capacitor.
Anything from 10 to 100 uf will work, depending on what you can
fit. 47 microfarad at 16volt would be a good choice for this rig, small
enough physically and large enough value.
In any rig using a LM386 that has a problem with "howling" or
oscillation, bypassing pin 7 is a good thing to try. In many designs
you can get away without it, but sometimes not. BTW, my SST 40
worked fine without it. I suspect the 20 meter version may require
more audio gain in the receiver, thus making audio feedback more
likely.
Fran, km1z
167. AE5X SST Mods and Comments
http://www.ae5x.com/mods.html
Wilderness SST
Increased Tuning Range
Two varactors are included with the SST with instructions to select the one that provides the tuning range you are most interested in. To use them both:
Install a small SPDT switch (RS 275-635) on the front panel.
Clipping the leads as short as possible, solder the hot side of each varactor to the outer terminals of the switch (hot lead of one varactor to one side of the switch, hot lead of the other varactor to the other side).
Using a short wire, connect the center lead of the switch to the hot side of the D4 mounting position on the circuit board. With the D4-side of the board facing you, this will be the left-side hole.
The two remaining leads of each varactor are now joined together and connected to the other D4 mounting hole.
Tuning Linearity
Linearity can be a (minor) problem with varactor-tuned rigs. To significantly reduce this in the SST, solder an 18k ohm resistor across the tuning pot between the wiper lead and the +8 volt lead. Experiment with this value as it varies from band to band and from one type of varactor to another.
Howling
(Terry W0PFR)
My SST 40m version also howled when the audio gain was at maximum. Looking at the application notes on the LM386 audio chip that is in the SST, I noticed that there is a comment that if the chip oscillates then an optional DC filter can be installed to prevent the oscillation. The filter is only a resistor and a by-pass capacitor placed in the lead supplying power to the chip. I have installed the modification and it seems to work. The changes can be done on the etched side of the pc board.
1. cut the trace going to pin 6 of U3
2. solder a 100 ohm 1/4 watt resistor from pin 6 of U3 to the contact next to pin 1 of U3 .
3. solder a .1mf disc cap from pin 6 of U3 to pin 4 of U3
Sidetone Level
(Wayne N6KR)
There are two ways to reduce the sidetone volume in the SST - reduce the AF Gain or, as recommended by the rigs' designer, Wayne N6KR:
Usually there is a good balance between the incoming signals and the sidetone in the SST. But you're right--if you have to turn it way up, the sidetone gets loud.
The only sure-fire way to mute the sidetone to a lower level is to insert a low pinch-off JFET like a J201 into each leg of the audio connection from the product detector to the audio amp. This is how I do it in the NC40A. Actually you can probably find other JFETs that will work; J310s are mostly low pinch-off, too. MPF102s will work if you hand-select them for low pinch-off.
The source leads go to the '602 and the drains to the original capacitors that go to the '386. Tie the gates together and add a 1 to 10M pull-up resistor from the gates to one of the source leads. Next, connect a diode from the gates to the key input. Test the circuit thus far by keying the rig: you should hear ZERO sidetone at this point, because pulling the gates low cuts off the JFETS, making them look like an extremely high resistance. If you hear a click on keydown, put a resistor (start with 1K) in series with the gate diode. If you hear a click on key-up, add a capacitor from gates to ground; start with about 0.1uF and see if you can go smaller. (It will depend on the pull-up resistor; 10M and .047 work well in most cases.)
Once this much is working, you can add a resistor *across* one of the JFETs (source to drain) to allow some sidetone to sneak through--as much or As little as you want. It will take a large resistor, something like 1 to 15M in my experience.
20 Meter SST to 15 Meters
(Roy AB7CE)
Dozens of requests on moving 20mtr SST to 15mtrs, so here is how I did it. If you make changes or improvements other than these, please let me know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook:
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO VXO
X6 = 25mhz crystals. I used two, one on top, one under board.
RFC3 = 23t #26 on T37-2(red). This was a critical value for proper oscillation and range. You may have to adjust a turn plus or minus, or compress or spread turns to adjust to desired tuning range.
RCV MIXER
RFC1 to 2.7uh(or close to it). Improves match to Filter and recieve.
PA
2.2uh molded choke from base of Q2 to ground.
As above changes were all that was neccessary to put it on 21.050 to 21.070 with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341) for two watts out. Its also very easy to move to 17mtrs by using same approach.
Addendum:
I put two crystals in both of my SST's to extend vxo range. One is 20mtrs and the other is one I moved to 15mtrs. With the MVAM108 varactors I was able to get about 20khz range. I was experimenting with different varactors I had on hand. Was not getting much difference. Then I tried a MV1404. WOW! The 20mtr version is covering from 14.013 to 14.064. The 15mtr version is covering from 21.039 to 21.073. Scope shows solid waveforms
across oscillator ranges. I don't know where to get them. They don't show up in my cross reference, so I don't even know what they are rated as. Mine were in a envelope of a dozen, that was in one of Dans Small Parts
20lbs of parts for $10.00. They are not listed on his current page. If any one knows what they are rated or where to get them, they might inform the rest of the list.
Miscellaneous
(John AE5X)
The TiCK keyer in my SST is mounted on the rear panel above the key jack. The new jack (required for paddles) is mounted above the RF Gain control on the rear panel and the pushbutton switch is mounted above the antenna (BNC) connector. Using a Xerox machine, I reduced the the size of the TiCK's program menu and laminated it to the top cover of my SST.
Also taped to the top panel is a tiny chart showing my operating frequency at 9 O'clock, 12 O'clock and 3 O'clock positions for both positions of the SPDT varactor switch.
To make tuning easier, a larger tuning knob is helpful. I use a RS 274-402.
168. SST and Tick-1 Keyer (duplicate info but good info)
Subject: Wilderness SST + Tick
Date: Tue, 07 Sep 2004 23:37:20 -0800
From: Jim Larsen - AL7FS
To: bonavita@swbell.net
There may be some clues here plus a contact that knows the answer.
W0CH is at mailto:qrp_ham@yahoo.com
"TICK Keyer Modification:
The TICK keyer uses the TICK-1 chip. It is powered from the 12 power line
through a 78L05 regulator chip. A 20K trim pot is used as a sidetone level
control with the wiper connected directly to the headphone jack. The paddle
jack was mounted immediately above the straight key jack. The programming push
button was installed on the front panel above the headphone jack."
Always great to hear from one of the original "greats" of QRP, Fred. You
communicated with me at a time when we both used US Postal service. Can you
imagine such a crude communications method? :-)
73, Jim
--
Jim Larsen, AL7FS
http://www.al7fs.us/
Anchorage, Alaska
As of 7 Sep 2004
C:\Files\Radio\SST\SST_MOD.DOC Page 103
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