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Antenna repairs @ DJ8OG

February 1st, 2020 | Posted by DJ8OG in Hamradio

I made some days vacation to visit family and friends in January in DL. As my station made more and more problems we prepared a list of tasks to bring the station back on air. I got help from DJ6KS, DG3FAW and DK6FX during my three days at the station. THANKS for your help during the cold weather, I couldn’t have done it without you.

In fall I discovered problems with the 40m and 30m beams from one to the other day. SWR was infinite and I couldn’t hear a beep on those antennas anymore. There must be a major issue as the 80m antenna on the same antenna switch was OK, I thought about a problem with the rotator, maybe turning and cutting off the coax. Knut was at the station and could confirm the cables were off.
OK, I could still operate on the BP-60 but I also had problems with the older Yaesu rotator. The indicator was bouncing and the antenna seemed to be off from targeting area. 160m had problems from the beginning when using the amplifier so we tried to find the cause. It might be the 1:1 balun inside the hybrid balun but as we don’t have an amplifier in the moment we can’t proof our theory.

I came to DL on Saturday and we made our first meeting on Sunday with Knut and Helge. Our goal was to bring both rotators back to work. I ordered a new Yaesu G-2800 which should be the easiest to switch just the rotator, and then check and fix the issue with 40m and 30m.
While I wanted to lower the tower, Knut found a damaged rotator cable and we quickly fixed it with some terminal clamps. We gave it a test as 2 out of 7 wires were damaged. The rotator was now turning and indicating correct. That was easy and very welcome at the freezing temperatures. Helge took the Balundesign hybrid balun apart. We got rid of the 1:1 balun and just stick with the 4:1 balun. 160m still looks good on SWR but the harmonics shifted a bit. Not a big deal except for 80m SSB were we currently don’t have an antenna. When the amplifier is back from repairs we can verify whether the fix is good or we need to go for something else.
Time to move on to the second tower. I took the safety harness and climbed up the tower. I found 3 damaged, pulled off, coax cables. The mast inside the rotator was loose, I had not installed a hex nut on the screws to secure the mast on the rotating side. The screw were not long enough, I remember I wanted to change the screws 🙂 some day. Knut ordered longer screws, we installed them with the hex nuts on and took the coax down to solder new plugs to it. After fixing the antenna and the coax we measured all antennas and could call it a day in the early afternoon, it was really cold and everybody wanted to go home. Before I left I installed the new EPROM which I received from Alpha Spid to prevent the BigRak from turning to 203° all of a sudden without a command (first tests are promising but I have to do some remote tests during the next weeks to see if the new EPROM is the solution)

I came back some days later to fix the damaged rotator cable and wanted to raise the west tower a bit to gain some meters in height. I adjusted the 80m CW / digital dipole as well. The weather wasn’t nice at all and I spent some time inside the shack to get warm. While doing some QSOs I discovered a problem with the transceiver. LED backlights were fluctuating and power levels jumping from 40W to 0W. After some trouble shooting I found a bad power supply. I hadn’t a spare one and so I called it a day and drove home. I got a new power supply from Difona the other day and Helge gave me the 6m big wheel we ordered from Wimo.
I drove a third time to the station and this time I got help from Andy, DK6FX. We never met before but know each other since almost 20 years. Andy wanted to meet and help me during my vacation, thank you! I installed the new power supply and tested the TRX, boom 100W and no fluctuate backlight anymore 🙂 Then started to assemble the big wheel for 6m when Andy came to the station. We had a nice day and after some correction on the antenna (I assembled it wrong) we could mount a mast close to the shack and bring the antenna about 10m high into the air.
I always wanted to do 6m last summer and used the 160m OCF dipole which had a good SWR. I thought about ways to add a beam to the tower but time and space didn’t allow it currently so we decide to go for the big wheel. I’m curious how the big wheel compares to the 160m OCF dipole 🙂

Knut fixed another issue on the remote connection and I installed a timer to reset the connection. Soon we should be back on air with the station.
I hope to hear you from SC or DL soon

Thanks again everybody for your help!

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