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Forwarded message:
From: thompson@mindspring.com (David L. Thompson)
To: K7LXC@aol.com
To: <towertalk@contesting.com>
Date: 97-03-12 14:18:38 EST
Steve,
I read your article in the April 1997 CQ Contest (I wonder if those April
fool articles will be understood by our DX friends). I wamted to comment on
using telephone poles.
My first tower was a telephone pole. It was a 68 footer that we cut the
bottom 10' out of as had been in the ground 12 years. The tower was planted
so that it was just 50' to the top. I used the mounting technique in QST
(Summer 1957) that also appeared in the ARRL antenna book and handbook for a
number of years. The rotor was held by a tee with the top coupling flexible
so you could lower the mast into or bend it through 90 degrees. We used a
TR-4 but later put a TR45 (just below the Ham-M). The top tee took the side
moments so all you had to worry about were the direct down moments. K4JC
(SK) used this for his three 90' poles with 5el 20M beams and 4el quads.
His article comparing quads and yagis is still valid altho some won't accept
it as he did no modeling (in 1968??).
My first beam was the Gonset Tri-Bander (18' boom) with 3el on 10, 15, and
20 with 5 total el on the boom. I later put up a quad described by Rod
W5HVV (a current subscriber ) with 4el on 10, 15, and 3 el 20 on a 20' boom.
(1966 QST). The quad was very heavy and was blown down by a tornado in
early 1969. I modified a Skylane with a 24 ft boom and then put up a TA-36
with 40 meter element (bad move).
Several other well known hams K5RFJ (now W4XJ) and K4EZ used an elevator
system on theirs.
I would not touch a pole unless I got pole spikes so it can be climbed.
These can start up high enough to ward off kids. Used poles are cheap, but
can be dangerous. I would cut off the part that had been the ground over 5
years. New 80 and 90 foot poles can be purchased for between $900 and $1500
and most who sell them have the rigging to dig the hole and set the pole.
Count on replacing the pole in 15 to 18 years if you live in the SE USA (not
sure about Washington etc.) I am told that they can be re-treated while
still in the ground now. Disposing of poles usually requires EPA treatment
or returning them to the pole yard for remediation or re-use.
73, Dave K4JRB
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