A Fun Couple Of Days On 23cms

Having recently completed the ~20W PA for 23cms I was looking for some activity on the band to see what difference the extra few watts would make. Unfortunately I had just missed the monthly UKAC session. Reading the UKMicrowave Digest I came across a posting advising that PI9CAM would be active on 23cms Moonbounce (EME) on Sunday 30th May. 🙂

The very small setup here on 23cms is still suboptimal in terms of receive and it’s definitely QRPp (very low power in 23cms EME terms). However, I have been decoding several stations that were using ~3m dishes so PI9CAM with their 25m dish (i.e. BIG Ears 🙂 ) might just be workable… right?

It was around lunchtime that I noticed PI9CAM on the MAP65 display, they were -14dB with me. Checking on the HB9Q chatroom others were giving reports around -4dB or -5dB. I decided that I’d try calling, if nothing else it would be a good stress test of the system. 🙂 Then another challenge hit me, Doppler! What frequency do I set the Transmit to? Is my potential QSO partner where they think they should be? What’s their receive bandwidth etc. I tried calling for several periods without success but then the penny dropped, Doh… I’d applied the TX Doppler shift the wrong way!!! Once this was corrected I called again and after 2 or 3 periods of calling I got my first “OOO” report back!


I responded with “RO” and waited for a “RRR”, the trace was bright but it wasn’t “RRR”, I got an “RO”. So I responded with a second “RO” and then the magic “RRR” was returned which I followed with the customary “73”. My first 23cms EME Initial was in the log.

The challenge was on, HB9Q was my next goal. Unfortunately I didn’t see Dan on 23cms on Sunday. However, he was QRV the next day.

Having left the gear monitoring 23cms and 2m EME I spotted that Dan, HB9Q was active. I made sure I got the Doppler set correctly and called. After a few calls, Bingo! I decoded my second “OOO” and we completed quickly. Dan gave me a -25dB report which was a great surprise.


It was great to have two new random contacts in the EME log. It has to be said though that all credit goes to both of these outstanding EME stations, and my thanks go to the Team CAM, PI9CAM and Dan, HB9Q. I’m certain my next EME contact on this band will not be quite so easy, but then that’s the challenge and the fun.  😉  I’m totally hooked now on the GHz bands and would encourage anyone to give 23cms and above a go.

My setup was a single 67 element yagi, G4DDK VLNA, 20W PA  (~8W at the antenna), SG-Lab TR1300 TVTR >> Anglian TVTR >> K3 and FCDPP + Linrad + MAP65

For interest here are a few other screen captures of various stations decoded via the Moon.

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What’s next? The VLNA needs to be moved as close as possible to the antenna driven-element and the number of N-type connectors reduced plus more power on TX!!!

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