Monday, May 6, 2013

Up the Tower

I seriously doubt that there is a Ham Radio operator alive that doesn't, at some time, want to put up a tower and directional antenna for HF operations. Having had several tower/beam installations over the years let me just say, erecting a tower and plopping a directional HF antenna on top is not a easy undertaking.

My first tower/beam installation was at our on-base house in Langley AFB, VA in 1984. It was a small installation as installations go: a 30 ft Rohn 25G tower and a TA-33jr HF tri-band Yagi. The tower was anchored to the porch roof of our quarters at the 15 ft level and the rest of the tower was un-guyed. It worked OK for a short tower and I learned quite a bit about tower and beam installations in the process.

My second attempt was a much bigger effort. I managed to procure 60 ft of steel tower (not Rohn), a Ham-IV rotator and a used HyGain TH7DX Yagi. I sanded, primed and repainted the tower, section by section. The rotator was sent off to Norm's Rotor Service for rebuild/upgrade. The TH-7 came from a ham in Hew Hampshire who had bought it off of a HyGain engineer. This tri-bander was originally a TH-6DXX that had been modified as a proof-or-concept design for their new TH-7. I quickly found that the current TH-7 manual was NOT even close to what I had! Eventually I found a manual on upgrading the TH-6 to the TH-7 and that cleared up a lot of problems I was encountering.

On a nice warm November day in 1995 we (six local hams and myself) put up the tower (now down to 50 ft in length) in one piece! It was bolted to the kitchen roof at the 22 ft level and the top section was guyed off three ways using steel guy wire, heavy duty turn buckles and Rohn 3 ft screw anchors. The TH-7 was assembled in the side yard and placed on the tower at the 55 ft level (there was a 12 ft steel pipe used as a mast). My son, Jamie, did the tower work for me. Mom refused to watch!

This tower/antenna installation lasted until it was taken down in 2011. It took a lot of physical effort for the seven of us to man-handle that tower into place and mount the beam. Bill, KA3QPQ, was the lucky recipient of the tower/beam. He had "friends" that worked on the overhead signs on PA interstates. So they arrived with a 65 foot boom truck and disassembled the beam and tower. It took a total of 2 hours for them to completely remove the installation! It took a LOT longer to initially put it up!! It always helps to have the proper tools to do the job!

My current tower/antenna project has been on-going for 4 years! When we first moved from Pennsylvania to Georgia in late 2008, I was able to procure eight sections of Rohn 25G for $150 (a great price, by the way). The local ham club had a Mossley Classic 33 HF tri-band Yagi for sale for $150 (another great price!) The only "long pole in the tent" was the lack of a suitable rotator. In mid-late 2009, I had promised Patricia, my wife (KB3MCT), that if I hadn't gotten the antenna project completed within 12 months, I'd sell the stuff and use the money for something we needed at the time. True to my word the antenna and tower sections were sold and the money put to a better use. Back to square one.

For the next two years I got by with a wire antenna. I did erect a loop but it only lasted for a few months before the gigantic trees in my back yard managed to bring it down during high winds. While these wires were adequate performers I was still lusting for a rotatable HF antenna that would permit me to work some serious DX.

In 2012 I was able to procure a Cushcraft A3S three element HF tri-band Yagi and a Glen Martin 5 ft roof tower. Thanks to the generosity of Bill Wilson, KJ4EX, and several of the Barrow ARC, I was able to mount the roof tower on  the main house roof and put the A3S on it along with a 6 meter Yagi. This was a mistake, plain and simple. The A3S being so close to the roof did not perform well on 20 and 15 meters. Additionally, with the antenna being so close to the it was picking up a lot of RF hash generated from inside my house from the various computers, routers, and other electronics.

Toward the end of 2012 I became the grateful recipient of four sections of Rohn 25G from Bill, KJ4EX, along with two more sections and a guy ring from Dave, N4KD, and a 25G top section, rotator plate, HyGain T2X rotator, and mast from another local ham. At the Birmingham hamfest I found a 36 inch Rohn house bracket for $50.  I now had the basics for a complete 70+ ft tower/HF beam installation at ZERO cost to me (house bracket not withstanding). Well, that's not quite true.....I had to send the T2X rotator off to a repair service in Alabama (cost: $200), 500 ft of Dacron guy rope (cost: $140), two screw ground anchors (cost: $55), plus an assortment of stainless steel (SS) bolts, nuts and lock washers for the tower and other things.

We (that would be Bill, KJ4EX, and the Boys from Barrow (B-f-B), and me dug the initial hole and put the first 15 ft of 25G in the ground and filled it with 800 pounds of concrete. After it cured, it was up with the next 2 tower sections. Elapsed time: 2 months. Finally, today (May 2nd, 3 months later), Bill and Bill Allen (another B-f-B) came over and put the final two ten foot sections of 25G up along with temporary guys.

Presently we have a total of 52 ft of tower in the air (that would be measured from the dirt to the top of the tower) and are now waiting until I prepare the 9 ft top section. Once that goes up, we will re-position the guy ropes, install the antenna mast (a 10 footer) and the antennas. The last thing to go up will be the rotator.

I still have one 10 ft section of 25G that I could put up, but that would make the overall tower height 72 ft which is two feet over the limit that Gwinnett County allows without a whole bunch of paperwork and bureaucratic hassle. I'll forgo the additional 10 ft since I hate paperwork!

Sometime within the next couple of weeks I will install the house bracket as close to the apex of the roof as possible. This bracket will strengthen the overall tower installation allowing us to reposition the guy wires from the 30 ft level to the 55 ft level. Since the overall wind load of the HF Yagi and the 2M/70cms vertical and a long-boom 2M yagi will be well under 10 square feet, additional guys won't be required.

Stay tuned for updates on the Bent Dipole Ranch's tower installation. In the mean time I have to get a remote antenna switch reconditioned and mounted, procure some lightening protection modules, get some ground rods driven in and connected to the tower and station ground. Whew!!! I get tired just thinking about that! Time for a nap.....just following my cat's sage advice....when in doubt, take a nap!

Vy 73
Rich K7SZ


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