Coax Change on the Beam

Last weekend I continued the antenna work theme by doing some maintenance on my own setup. I have a 3-element 4-band beam on a 30-foot tower that has been giving some poor SWR readings lately. I decided to start with the coax since the line that was up there was 12-year old Radio Shack RG8, and the Tucson sun and monsoon rains can really wreak havoc on just about anything.
I had a couple of lines of Times Microwave LMR400 laying up on the roof, attached to a VHF beam that is currently out of service, so I decided the easiest approach would be to just swap the lines. I climbed the tower and it took me about an hour to make the changeout. While I was up there I noticed that the fiberglass insulators used on the Cushcraft antennas (I also have a small VHF/UHF vertical) were really trashed.
Anyway the change in transmission line seems to have helped quite a bit but I still have an unacceptably high SWR on 10 and 15 meters. 20 and 40 are just fine. I'm guessing there is a problem with the traps but it's going to be a big job to repair or replace the antenna.
It's a bummer that while the antenna is arguably the most important part of any ham radio installation, it's also the most difficult to maintain.

Up on the Rooftop

Last Saturday I joined AA7HX, KB7LMI, and K2VNT for a little bit of antenna work. We were making repairs to the K7RST repeater here in Tucson, which operates on 448.325 MHz. The mast holding the antenna is a push-up type and had slid down quite a bit; that resulted in slack in the guy lines, which caused a bending of the mast.

Although we were able to push the mast back up and lock it down on the bottom section, we couldn't work on the upper sections without taking the whole thing down. Also, the bending is probably not repairable. So we improved it and probably lengthened its life a little, but more work definitely is needed.

The picture shows me looking up, with Ted and Dave standing nearby. More pictures are on my website.

Ten-Ten Convention

This being a new blog, I'll post a few "catch-up" items. It also might take me a few posts to learn how to best use this blogging system.

Back on August 9th, 2007, I attended the Board of Directors meeting for Ten-Ten International Net in Omaha, Nebraska. On the 10th - 12th, we had the biannual Convention. It was a great time, with close to 200 10 meter enthusiasts spending their weekend together. We held "parking lot" nets, including both voice and psk31 nets.

Despite the poor propagation at this point in the sunspot cycle, 10 meters is alive and well; we continue to bring in many new members each month. The membership numbers are right on the verge of passing #75,000. The Board voted on several enhancements to our member benefits, including my suggestion of making all 10-10 awards free to members. I'm sensing an upswing in ham radio interest these days - it seems like more hams, including myself, are eager for action. Perhaps it is because we've all been waiting long enough for the cycle to head back up. I think there is also some increase resulting from the FCC's dropping of the code requirement back in February. I cannot wait to see what it will be like when propagation improves.

I set up a little station in my room while I was in Omaha, using a Yaesu FT-817 and an MP-1 antenna. I used this setup for both voice and psk31 contacts.

To see more photos of the event, go to http://www.kr7rk.com/tenten2007.htm