I'm very happy that I was finally able to finish my first Earth-Moon-Earth 🌍-🌕-🌍 (#EME) QSO last week. It only worked out because Bernd, DL7APV did all the work with his amazing 128 (!) x 11 ele 70cm Yagis. He has a gain of incredible 33.7dB over a dipole:
On my side it was only a tiny single 15 ele Diamond A-430S15 with 14.8dbi gain, so 12.65 db compared to a dipole and a 3D-printed tripod mount:
Here is the QSO in Q65 (60B) mode:
This is what Bernd, DL7APV saw on his side:
By the way, the moon was not visible, so I used the ISS Detector Pro App with augmented view (iOS) on my mobile phone. The white circle is the moon:
Thanks Max, SA5IKN for the idea 🤯 and all tips and infos and Dragan, 4O4A for moralic support. 😊 Now i can confirm that it's possible with a good satellite (especially greencube) setup. No preamp needed and also no gpdso needed. not even a good cable needed.
Summary of my gear for my first EME contact:
- IC-910 @ 75W (maybe less because of battery and SWR)
- 18 Ah LiFePo4 Battery
- no preamp
- 3m cheap german RG-58 "low loss", Telegärtner connectors, self crimped
- no gpsdo (WSJT-X: Max Drift 50, F Tol 200)
- moon was not visible, used issdetector pro app with augmented view (iOS) for moon tracking
Here is my LOTW confirmation of my first (and so far only) EME contact:
Paper QSL also arrived super fast:
Because many people have already asked me:
No, you can't just point at the moon and make a QSO if you only have such a small portable setup. QSOs are only possible with 4 stations on the 70cm band: DL7APV, NC1I, HB9Q and UA3PTW. These are the best EME in the world on 70cm and their antenna doing bacially all the work. So if you want to be successful, you should sked with one of these four stations. There are still three of them on my list. I have already written to NC1I.
The Magic of Moonbounce:
To achieve an EME contact, amateur radio operators transmit their signals towards the Moon. These radio waves travel approximately 384,400 kilometers (238,900 miles) through space and are reflected off the lunar surface back to Earth for a total distance of 768.800km (!!). The process of bouncing signals off the Moon's surface is known as "moonbounce" or "moonbounce communication." Despite the long distances involved, the round-trip delay is only about 2.5 seconds. This is the offset time that is clearly visible on my and also on Bernds screenshot.
For more information, see my Twitter post: https://twitter.com/DK9JC/status/1679811411302653953
