August 2013

The Amateur Amateur: Reseeding the Antenna Farm
By Gary Ross Hoffman, KB0H

In April of this year I lost most of my rooftop antennas to a storm (see The Amateur Amateur: Mastless in Missouri). That was traumatic enough, of course, but even more stressful was the hole in my roof. My main mast didn't go down without a fight. Prior to the storm I'd had four VHF/UHF antennas up on the roof, plus two scanner antennas, and also a stretch of wire connected to a SG-230 antenna coupler for HF operations. Three of the VHF/UHF antennas and the SG-230 box were all on the same mast. It was too high. It weighed too much. It wasn't guyed. And it came down.

That left me with one VHF/UHF antenna and the two scanner antennas. I managed to re-purpose one of the latter, so I was able to do my weekly ARES duties and still run an APRS station (Automatic Packet Reporting System). That was better than nothing.

Fortunately, my insurance company was on the ball. They came out quickly, assessed the damage, and even found old hail damage of which I wasn't aware. Rather than a localized patch, they decided they'd pay for a whole new roof.

Wow! That was both good news and bad news. I could've probably had the roof patched fairly quickly, but getting a whole new roof meant a month-long wait, and I was anxious to get more metal into the air. One of my two surviving masts was mounted on a tripod. There wasn't much point in trying to put anything else on that mast since it would all have to come down before the roofers arrived. The other mast, however, was bolted to the north eave of my house. I phoned the roofers and asked if I would have to take it down as well. They assured me that I would not.

Okay! That gave me something I could play with. As it happened, that mast held my oldest antennas, two Radio Shack scanner discones, and a defunct anemometer. The discones were somewhat beat up, having gone through a number of hailstorms, and the home-made standoff connecting them to the mast was my very first effort. Basically, everything on that mast needed to come down anyway.

I wasn't sure exactly what I was going to do. I figured I'd keep the discones, fix them up, and replace the old RG-58 coax with something decent. The anemometer could go, since it no longer worked. I thought maybe I could mount a nice Diamond X50 in its place. Yeah, cluttered, but I have lots of ideas and only a limited number of masts.

That project never took place. Oh, I climbed onto the roof with my tools. I started unbolting the mast. But when it came to pulling the base of the mast out of the brackets on the eave, I realized that I would have to stand at the very edge of the roof and wrestle with a lot of ungainly metal and wire, all of which just might want to argue with me about exactly where we were going to go.

And it was a long way down to the ground.

I played it smart. I re-bolted everything and got down off the roof. By ladder. I still wanted to remove that mast, but I needed to rethink the whole process. I definitely didn't want to fall. I might just survive, and then I'd be in big trouble with my wife Nancy.

With the eave-mounted mast project on hold, I needed to shift my focus. In fact, I needed to shift the mast itself. Even if I managed to get it down, putting it back up again would be just as terrifying. No, whatever I had planned to put on the eave would have to go somewhere else. Could I jam everything onto the tripod-mounted mast? Not a chance. I'd already scheduled another clutter for it.

I needed a second tripod. And a replacement for the one antenna that had busted when the old mast had come crashing down.

Ah, spend money. Sounded like a plan.

I got out my sketchpad and drew a picture of the roof-line with two tripod-mounted masts on it. I figured that I could put a total of six antennas on them. Yes, I know. That's too many RF sources too close together. But my coaxial cables already had a very long route from my basement shack, through various channels, zigs and zags, before popping out of an eave vent and up to the roof. It's a compromise.

Did I actually have a use for six VHF/UHF antennas? Silly question! A ham can always find uses for any number of antennas! In my case it was: Two antennas for 2 meter voice, two dedicated to 2 meter digital modes, one for 1.25 meter voice, and one for a scanner. The only problem with that equation was that there were just five decent coaxial cables running up to the roof.

Spend more money. It was for a worthy cause, right? And this time I opted to get really high quality stuff.

The roofers came out in May and did their thing. The new roof looked so pristine that it was almost a shame to put anything on it.

Well, I felt that way for about ten minutes. After that I was itching to get up there and start reseeding my antenna farm. I just needed two things:
  1. The presence of my safety officer (Nancy)
  2. A dry day

Oh yeah, it rained that May. In fact, it rained most of April, May, and June. Especially on the weekends.

I can't remember how long I had to wait, but eventually both Nancy and sunshine were available. I scrambled up onto the roof and installed one of the tripods, a mast, and a VHF/UHF antenna. Aaaaahhhh, it felt good to be back on the air.

At the next opportunity I installed the second tripod, another mast, and a second VHF/UHF antenna. The very next day I put a standoff halfway up the first mast with two Diamond X50 antennas on it. The weather was cooperating and I was on a roll.

With four antennas now up it was time to assess their capabilities. Everything I had just erected was lower than my original array, and I wanted to see how much that affected my ability to send and receive.

I spent some time down in my shack testing everything and learned some very interesting things. I could still reach most of the repeaters I normally used, but my digital efforts were severely hampered. My highest antenna could not reach any Winlink station and could only marginally connect to the Missouri Emergency Packet Network. Intriguingly, though, a lower antenna with higher gain was able to get through. That was enlightening.

The higher antenna was a Diamond D130J discone and the lower one was a Diamond X300A. (Okay, so I like Diamond antennas.) I decided to put the X300A a bit higher and connect it with the highest quality coax I could afford, 100 feet of Bury Flex. So, down came the mast, the coax was switched, the mast went back up, and....

Nothing. I couldn't get out on the X300A.

That was distressing. Not just because something didn't work, but because it meant that I was going to have to make additional trips to the roof. Either the new Bury Flex coaxial cable didn't work (how could that be possible?) or I had damaged my new X300A antenna. I didn't relish either scenario.

I put an ohmmeter on the Bury Flex connector at the shack-end of the cable. Oh boy, there was a short. And since I had purchased the Bury Flex with the connectors already installed, I knew that I must have done something bad to my expensive, brand-new X300A antenna.

I climbed back onto the roof and took down the mast again. Not knowing what I could possibly do to repair the antenna, I delayed the inevitable by finding other tasks to perform. I disconnected the coax and gave it another test with the ohmmeter.

Whoa, it was the Bury Flex that was shorted! That was inconceivable! I'd bought the cable with pre-installed connectors because I knew that if I installed them, there probably would be a short. It never occurred to me that the vendor or manufacturer would pre-short the cable for me.

Analysis: The Bury Flex had a short somewhere. It could have been at the shack-end connector, the roof-end connector, or (shudder!) somewhere along the cable itself. If it was in the cable itself I would have to remove the whole 100 feet of coax, something I really didn't want to do. It had taken hours to route the blasted stuff.

Sighing, I started with the shack-end connector. If that was the culprit, it would be the easiest to repair. Cringing, I snipped it off. I put the ohmmeter on it, and Yes! There was a short! Just to be sure that there weren't multiple problems, I checked the rest of the coax again, and found no more shorts. Whew!

I dug through my parts box, found a fresh PL-259 connector, warmed up the soldering iron, and put the new connector on the coax.

And it worked.

Somehow The Amateur Amateur had managed to do a better job than the professional who had put on the original connectors. What a strange world we live in.

Now I had just one final multi-part task to perform before my antenna farm reseeding project was done. I had to take down the eave-mounted mast, refurbish the damaged discone antennas, yank out the ancient RG-58 cables and replace them with better quality RG-8, stick the discones onto a new home-built standoff and then mount it on a mast.

The only really significant part of that task was to get the eave-mounted mast down without killing myself. What I really needed was some way to keep the mast stable while I unbolted it from the bracket on the eave. My tallest ladder wasn't high enough to be of any use. I considered and rejected bucket trucks, helicopters, mountain climbing gear and a host of other wildly improbable schemes. And in the end I decided to use my most dependable asset: Nancy.

Working very slowly and very carefully Nancy and I got the eave-mounted mast down. (How did I get it up in the first place?) I helped her get down from the roof, then spent the next couple of hours taking care of the rest of the tasks. It was tedious, but nothing untoward happened.

Everything works and I am happy. I learned a number of things. First, a higher gain antenna may get a signal out better than a physically higher antenna. Second, I should always test my coax before routing it. Third, and most importantly, you've just got to love a woman who will climb onto the roof with you and help you with your insane schemes.

Shorted connector

partially restored farm
Halfway finished

disassembled mast
Eave-mounted mast, down and disassembled

the farm reseeded
The Farm Reseeded

cable cleanup
One last job, cleaning up the cables

E-mail Gary Ross Hoffman

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