22-Oct-2019 SHF UKAC 3cm and 13cm

I worked a few locals on 3cm, collecting my partner from the station in between. I could just hear David G4ASR in the noise, but not strong enough to work. I had tilted up the dish a tad in order to clear the ridge of trees. Anything south is a problem. I failed with John G4ZTR. Kjeld OZ1FF didn’t respond to my meeps on ON4KST KST chat. So about 400 points on that band maybe.


I had taken the relay box down from the pole the previous day for 13cm. That Tue eve I finally found the fault. I had added an LED to show when the relay was on transmit. This drew just enough current to have the side effect of latching the relay to receive (energised), so no RF out on transmit! I disconnected the LED & the relay worked. So I just lashed it up on the bench. I worked Denis on about 1W at the antenna. Then I cabled in the linear with some attenuation to get 20-25W for a couple more. I tried John G3XDY near the end of the contest and logged what I heard. Then I timed out.

Denis G3UVR was easier to hear on 3cm.


I’ll try a low-current LED. If I get a good spell of wx, I’ll put the box back on the mast & get the pre-amp nearer the antenna. I haven’t tried the relay or pre-amp before. The Narda relay is nice & chunky, but its markings suggest it is only rated up to 1 GHz.  I may have made the Noise Factor worse on receive, but I have some more dB on transmit. I’ve included a Band-Pass Filter in the box, so that worsens the NF a little more.

At least all the control circuitry seems to be working: sequencing, 12V to the pre-amp, 24V to the antenna relay etc. The 40el Wimo yagi is back up on its jockey pole so I can do terrestrial 13cm again. It has been nearly a year since I started upgrading 13cm with a pre-amp and linear.

The SG-Labs transverter is now in a box in the shack, with reverse-polarity protection, sub-band switch: 2.3 Ghz, 2.32 GHz and 2.4 GHz, power switch, ref. osc. input switch, indicator LEDs, power switch and a nice Anderson power plug. I want to add drive power switching and a monitor meter.