Thanks to everyone for the comments so far.
Although I do have enough Rohn 25 to make up a 70-footer -- and would love to
have a 70- to 90-foot tower right now -- the cost of properly guying and
anchoring such a tower exceeds my short-term budget.
The big steel tip-up masts one poster mentioned are fine business -- but the cost of the
steel is close to $1,000, and my welding skills are meager at best. :) I already have
the towers, which makes them essentially "free."
What I need is some input on whether a telephone pole or a cemented in place length of
"big timber" will allow me to raise and lower a 40-foot Rohn 25G tower reliably.
Other than the mast and the fiberglass pole on top (weighs only 3-4 pounds),
there will be no antennas on these towers and they will never be climbed.
So, if anyone knows whether a pressure treated wooden beam will sufficiently
insulate the tower/vertical from ground...and whether a telephone pole or other
timber can handle the stress of keeping the tower vertical (and raising and
lowering)...those are the killer questions.
The tilt-over Rohn 25 towers for the back yard will be topped with a 10-foot
steel mast and then a 20-30 foot fiberglass pole, which makes for a pair of
70-80 foot identical vertical antennas, which I hope to eventually phase on the
low bands. Otherwise, the towers/verticals only have to hold up one leg of a
wire antenna.
Remember: I've spend the past 12 years DXing with an attic-mounted horizontal loop that
was 25 feet above ground. In casual operating and contesting I managed to work more than
175 DXCC entities with a maximum of 5 W. My "new" antennas -- a pair of
70-80-foot phasable verticals over proper radial fields, a big horizontal loop at 50
feet, an affordable HF beam at 50 feet (prolly a Tennadyne T-8), and Yagis for 6 through
432 at 50 feet -- will give me a 20 to 50 dB boost, depending on the band, and will be
quite enough to keep me moving forward for a while. When things settle down in a season
or two, and all of my honey-do items have been taken care of, I can put up a 90-footer if
desired. (Well, of course it's desired!) But my piggy bank has to recharge a bit first...
After getting started in 1977, I still need to confirm one zone (the one with
Thailand in it) for WAZ. Yes, I could do it at a friend's station or with a
remoterig station, but that sorta ruins the fun for me. With the antennas I
just described, I should be able to finish 5BDXCC (9 band?), make a couple of
moonbounce QSOs on 2, finish VUCC on 2 and 432, do better in QRP contests, etc.
Trust me -- those things, although not the best possible antennas, will seem
like Death Rays compared to indoor hamming.
Thanks,
--Kirk, NT0Z
My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)
On Sunday, May 15, 2016 2:54 PM, "ScottW3TX@verizon.net"
<scottw3tx@verizon.net> wrote:
In fact I googled "W3GM falling derrick tower" and there are several links!
Best regards,
Scott W3TX
On May 15, 2016, at 2:53 PM, ScottW3TX@verizon.net <scottw3tx@verizon.net>
wrote:
Hello Kirk,
That sounds a lot like the falling derrick method of raising/lowering a tower.
The original W3GM station did this with perhaps all his towers.
Another option, maybe more elegant, is the hazer type thing. There is a copycat
that is better than the original but cant remember its name.
Sounds like a great setup with several shorter towers!
Best regards,
Scott W3TX
On May 15, 2016, at 3:26 AM, Kirk Kleinschmidt via TowerTalk
<towertalk@contesting.com> wrote:
Hi gang,
After 12 years in a condo with attic antennas, I will soon have a "short" acre
on which to farm some antennas. I expect to try a few low-band types that are new to me,
and will be looking for some feedback and input. :) This might get a bit windy, so
please bear with me.
First up -- Tilt-over mount for Rohn 25:
In central MN, when I was a new ham in the '70s, because we were in a "fringy" area for
TV reception, MANY homeowners had 50-foot tip-up masts to support big TV Yagis and small rotators.
Back then, the 2- to 4-inch steel pipe required to construct these tip-ups was reasonably trivial
in cost. A 50-foot single mast was made from several "telescoped" sections of steel pipe,
welded or bolted together. Two parallel steel pipes were sunk into the ground and cemented in
place, with 10 to 15 feet of the vertical supports sticking out above ground. The vertical tip-up
mast was centered in the two fixed uprights, and a top-mounted pivot allowed the mast to be raised
and lowered with a bottom-mounted winch.
All or most of you know what I'm describing, so I will now stop! My point is,
the steel with which to make such a tip-up mast now far exceeds the cost of
buying abandoned or unused Rohn or Rohn-style towers. The question is, how do I
make a reasonably priced tip-up or tilt-over mount for these things?
At my new QTH, I have four Rohn towers to play with. All were donated to my cause,
purchased for $100, or were "free if you'll just take the thing down and haul it
away." I have two 40-foot Rohn 25s with 3-into-1 top sections, one BX64 (that will
probably stop at 48 or 56 feet for improved wind load capacity [to be discussed later],
and one 40-foot BX40.
My "benchmark" antenna over the years has been a full-wave horizontal loop (triangle
shaped) cut for about 5 MHz, fed with open-wire line and a ground-mounted autocoupler. And because
of the lay of the land at the new place, I plan to install three towers in a triangle configuration
(no mature trees). The "big" tower (if you can call a 48-56 footer big :) will be near
the house. It will eventually host an HF beam. It will also hold up one leg of the horizontal loop.
The BX40 will go next to the garage and will host beams for 6, 2 and TV.
The two 40-foot 25Gs (the second and thir
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