A LIGHT DUTY PVC MAST
By WB2VUO
My brother, John, KB2SIL has had one of these up for the last 4 years,
which considering the CNY winter WX bodes well for the survivablity.
This was posted last year, so if you think you have seen it before, you
probably have...
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This was originally posted on packet, and published in the BARK
(Brockport Amateur Radio Klub) newsletter and the Rochester VHF
Journal...Keith, WB2VUO
_
PPM: A Light-Duty PVC Pipe Mast
Over the 25+ years that I have been a ham. I have seen a few antenna
supports, [ and have built a few, myself ]. One of my brothers, John,
KB2SIL, has come up with a light-duty, inexpensive and easily built PVC
Pipe Mast, PPM for short.
On John's first attempt on the PPM, he acquired (3) 10-foot lengths of
1 1/2" NPS PVC pipe. The actual outside diameter of this is 1.99",
with a nominal ID of 1 1/2". He put the three lengths together with
straight couplings and PVC cement. However, when he tried to raise
the mast into the air, the cemented joints failed catastrophically,
resulting in PVC hash and scraps all over the back yard. Something
else needed to be done to improve the mast mechanically.
In PPM, Part II, John used a piece of the PVC for sleeves at each
joint, cutting a pair of 2-foot lengths from some of the scrap, and
splitting them lengthwise with a hacksaw. These split sleeves were
held in place with four stainless steel hose clamps, two above, and
two below the joint. This proved to be entirely adequate, and he set
the mast up at the end of the house. Using a mast bracket, re-drilled
for a larger U-bolt, and a set of light Nylon guys at he 20-foot
level, he erected an 80 - 10 meter G5RV. This put the feedpoint up at
29-feet, just right for the 300-ohm twinlead, and the plastic mast
doesn't affect the balance on the line!
As a bonus, and seeing that he didn't have his ticket back then, I
checked out the antler for him. It plays as expected on not only 80 -
10 Meters, but also on 6 Meters. We were able to raise a 6-Meter
repeater about 40 miles south of his QTH with around 3 watts. The SWR
was normal for the HF ranges, being best on the 20 meter band, and was
within the ATU's adjustment range on all the other HF bands.
John is in the Syracuse area, with a fairly well-sheltered back yard.
Out here on the windswept flats [swamps] of Bergen, I wouldn't expect
the PPM to survive, unless I guyed it 6-ways to Sunday, but I am
eyeing the leeward end of my barn as a possibility. I would think
that the PPM would work well in almost any urban/suburban lot, and
being PVC, one wouldn't have to worry about corrosion and/or water
damage.
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If you try out John's PPM, drop me a line here.
72/73, Keith, WB2VUO.
My thanks to Keith for allowing me to use his file - Frank, G3YCC.
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