[TowerTalk] Tilt-Over Rohn 25?

Sun May 15 20:24:53 EDT 2016

We used to tip up and down 40' of R25 for Field Day. We used the local 
community college baseball diamond and one of the dugouts for our base 
of operations.

We had a Rohn tilt base for R25 and used to lift it with a block and 
tackle one of the OT's would bring every year.
We hooked that up to the bumper hitch on my Dakota pickup.

That tower was guyed in three directions with screw in anchors and was 
climbed with no problem or trepidation to install the TH3. The base 
plate was "nailed" down with 4' sections of rebar through the base bolt 
holes that had an L at the top which would allow us to get an old 
latching style car jack under the rebar to pull it out when field day 
was over. That rig survived and 80+ mph severe thunder storm one year. 
Storm was so bad we had members of the club getting out of bed and 
driving to the site to look for survivors. No worse for wear. Radio's 
didn't even get wet.

You'd have to get a mechanical engineer to confirm but I think a 12' 6x6 
sunk 6' in concrete would be enough for 40' of Rohn 25. How long is the 
mast your planning on? If you're planning on 20' of mast out the top 
then the lever just increased 50%. If you're trying to self support this 
lash up forget about it. Rohn 25 is rated at 30' for self support and 
not much load. The mast and vertical would probably be 3 or 4 sqft of 
wind load.

Your going to need a winch and tilt plate. Might be cheaper to guy it 
properly.
3/16 EHS and associated hardware including 4' screw anchors are probably 
cheaper than a 12' 6x6, cement, tilt plate and winch.

On 5/15/2016 5:29 PM, Kirk Kleinschmidt via TowerTalk wrote:
> 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 at verizon.net" <scottw3tx at 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 at verizon.net <scottw3tx at 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 at 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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-- 
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441

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