One cool antenna

I’ve got a cool antenna. Make that a cold antenna. This morning I discovered that the resonance of the 80/160m antenna shifted down in frequency. Overnight there has been some ice buildup which changed the antenna impedance. Just out of a warm bed into a warm shack, I had to face a thermal shock. I took a broom and went outside to shake the ice off of the elevated radials and the vertical wires. This didn’t help.  Most of the ice just stuck to the wires.

The SWR was still ‘within limits’ so I decided to defrost the antenna with brute RF power. I’ve done that before. The night before CQ WW CW 2005 it started snowing. Back then I used a KLM KT34XA yagi and the linear loading elements were clogged with a layer of snow. This shifted the resonance way out of band. So that morning when I wanted to play on 20m, it was a no go. I tried to load the antenna with the tuner and gently gave more power, a couple of hundred watts. With SWR 5:1 soon the snow fell off the coaxial cable. A practical experiment to demonstrate Joule’s law with coax losses. Soon after the coax the antenna followed and with some left and right turning, the antenna got usable again. I applied the same technique this morning. With SWR only 2.2:1 on 80m (it was 1.4:1 without the ice) I pumped 800W and started running. Every other minute I had to retune the amp and SWR was dropping from 2.2:1 to 1.6:1 on both 80m and 160m. Too bad no DX was worked. I only worked a bunch of EU on 80m.

I also managed to sell the TS-850. Not quite at the price I had in mind but still an acceptable trade off. I sent it to a Kenwood repair centre last month to fix the well known issue with the carrier board. The issue with the leaking capacitors and the broken DDS chips. Google told me all about it. They installed a new CAR unit and the rig is good to go again. I tested monitoring audio with the headphones and everything worked again. Saturday I wanted to show the buyer that the rig was working OK but soon we discovered that the audio from the speaker was awful. I didn’t test the rig with the speaker, I only listened through the headphones. That audio was ok and the external 8 ohm speaker output was clean too. So it was definitely an issue with the speaker. We decided to open the rig and took the cover off. With the top cover in my hand and the speaker wire stretched between cover and PCB, the speaker’s output was clean too. It turned out the Kenwood service technician had taken out the speaker and mounted it 180° turned. That way the speaker’s wire and the speaker got jammed somewhere rendering the audio very distorted. It’s just a matter of loosening screws and turning the speaker and the problem got fixed. I was glad to fix this issue so fast. I’d hate to send the rig in back for repair. All is well that ends well, so the ham piggy just gained some weight.

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