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Over the past two years I have been wondering if we might be able to manage an EME (Earth Moon Earth) contact from the club, now that we have Dale's mega 2m amplifier on loan.
I'd listened out at the very bottom of 2m during the major 2m EME contests to see if I could hear any activity, but couldn't claim any success. We do have a very long feeder run, with the preamp at the wrong end of it ! Even with a large amplifier, if we couldn't hear any signals coming from the moon it was going to be a no-show.
Dave W5UN in Texas has one of the biggest 2m EME
stations in the world (with something like 48x16 ele). Indeed I am
told he can hear his own echoes off the moon with only 4 watts !
After reading Dave's primer for EME on his web site http://web.wt.net/~w5un
Dave suggested that anyone with a decent antenna
system, and a couple of hundred watts at the antenna should be able to
manage an EME QSO.
I asked Norman G3FPK, the RadCom VHF/UHF columnist about the best place to start, and he suggested I dive in and ask for a sked !
I emailed W5UN and requested a sked - and things moved very quickly from there. The sked was arranged for Saturday July 10, when the moon would be close to the earth. This was just after VHF NFD, and Dale G3XBY had also allowed me to use his IC275 which had a better receiver and filters we had been using over the Field Day weekend. I could also drive the amp a bit harder with the 275 than I could the club's FT736... ! The days before the sked I was on the Internet finding out the coax loss figures over the run, and trying to work out the link budget. I was worried that there were too many boxes with negative figures in. This might have ended up an ESP QSO !
The sked lasted for an hour - I would transmit for 1 minute using CW on the odd minutes of the hour, and W5UN would transmit on the other minutes. As signals are very very weak after a half million mile round trip - normal QSO procedures do not apply, but consist of an exchange of callsigns, and a confirmation of reports. W5UN can elevate his antennas, but as we can't here at Wythall, our sked would only work just at moonrise or moonset when the moon was on the horizon and I could point the 2m yagi directly at it.
For the first 40 minutes nothing was heard and I was convinced the coax loss was too great. Pete G1DUO had popped in to the shack to see what would happen - but there was only noise to be heard. When we transmitted the lights in the shack dimmed !
As we are only a very very small station in terms of EME, our own setup was not good enough to hear our own echoes.
As the moon got to the horizon we got an extra bit of gain (ground gain) and I could hear my own callsign coming back !! By the time we were sending 'R's and '73's to each other the signals were strong and above the noise - I could pull the headphones out of the radio and Pete (who had fortunately just come back from the bar in time!) heard the signals to prove I wasn't making it all up. I then gave Dave W5UN a landline call afterwards to say thanks which was a lot easier than all that mucking about with the moon !
It will be difficult to improve our station, as we will always have a 50m run of coax to live with, but there are other stations out there with similar setups to Dave's if anyone fancies another go sometime.
It was certainly my most memorable QSO !
