back to 2025.07.06 K0DV beam troubleshoot

2025.08.09 repair:


We had scheduled to do the work on Monday Aug 4, but the week before the city got hit with two powerful storms
that did a lot of damage, and the crane crew had to do some emergency rebooking. We didn't get enough notice
for me to change my day off work, so the crew offered to reschedule us for Saturday the 9th. Normally there's
higher rates for weekend, but they waved that due to them being the ones that had to reschedule instead of us.

Weather was looking sketchy, with rain moving in late that morning, but hopefully it holds off long enough.
Things never go as planned, and always take longer, but we gave it a shot. I was up working from about 7:30
to 11:00, and I got down not long before an intense downburst hit the area.

I was expecting to be working in a small bucket like you'd see a lineman or tree trimmer using, but this was a
much larger arrangement. The crane lifted up a heavy metal basket that was more like a hot-air balloon basket,
but made of metal and with lower side walls. Despite being lifted with just a single steel cable, the mass of
the basket kept it remarkably stable. I could just walk around inside it for the most part, with almost no
turning or shifting in balance. It was also pretty roomy, maybe 4 or 5 feet square. The driver was skilled
at positioning the basket, and had hand-held radios for us to communicate, although mine went on the fritz at
about the 2-hour point.

The balun was pretty much exactly as expected, the ground wire had broken from the coil and was hanging from
the center conductor. I got it cut loose and came down to assist Doug in getting it rebuilt. We were in a
bit of a hurry since we were "on the clock" while repairing the balun, but got it squared away pretty quickly.

Unfortunately the element cannot be replaced in-situ. The antenna uses a double boom, with one above the other,
and this element is on the lower boom. The element slides in from the side, and is attached with a bolt that's
accessed through a hole in the top of the boom. But being the lower boom, the upper boom is in the way. So
I'm pretty certain the booms have to be separated to relace that element. Doug said the loss of just the one
element hasn't had much of an effect on tuning, so it'll have to stay as-is, at least for the foreseeable
future.

Although we tested the antenna as soon as I got the balun replaced, Doug ran into problems with the tune of the
antenna and lost rotor control during the event, both with no apparent cause. Fortunately, the mystery
bugs both disappeared after giving the systems some time powered off to reset. So it appears to be a successful
repair job.

I had no time to take any pictures or video, but Doug did take some pictures and a few videos from the ground,
which I've included below.

2025.08.09 07.24.31	2025.08.09 07.27.23	2025.08.09 07.27.29	2025.08.09 07.43.27	2025.08.09 08.24.03	2025.08.09 08.24.17
2025.08.09 08.24.42	2025.08.09 08.24.56

2025.08.09 07.11.18.MOV (20 MB)	2025.08.09 07.21.25.MOV (63 MB)	2025.08.09 07.45.44.MOV (3 MB)

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