EME
A long-standing unreachable love comes closer
I had been away from the radio for 25 years. But the last thing I eyed before jumping into the corporate world was EME. In the late 90s, there was no proliferation of modern digital modes. Thus, reaching the Moon and back was beyond the capabilities of most humans. But not completely impossible. And that was luring a lot, though I had virtually zero practical opportunity to implement the dream into reality.
It is time to catch up 🙂
2026.Apr.25
Planning the Moon meetup using the Moon Tracker app. Since the 6m 7-ele OWA Yagi is a weak antenna for EME, the plan was to use the ground reflection and to have up to 6 dB gain, which is a lot. Effectively, it is like four the same antennas ideally combined and facing the Moon up.
It is a lot of free gain. But, of course, the guys on the end of the EME connection must have either the same low-angled Moon, which is a low-probability event, or a properly rotatable antenna with the elevation as well.
Since I didn’t even have a 2m or 70cm transceiver, but I couldn’t wait anymore, the 6m 7-ele OWA Yagi could be an opportunistic option and lovely Icom 7300 as the main engine, if not making a QSO but receiving somebody over the Moon.
When I started, I didn’t have an LNA, but I quickly assembled one as a part of future remote Antenna Switch + LNA + Sequencer + IMU for antenna positioning.
Yes, I purchased a few reputable transistors to make the LNA as well, but I purchased a couple of ready-to-use (and very inexpensive but with unconfirmed NF or P-1 compression points LNAs on Alibaba). It was aimed at saving time. It worked out well 🙂
The same housing was expected including the antenna switch that consisted of two relays – to provide the maximum TX/RX isolation because sooner or later I planned to hit it with 500-1000 W of 6m power. The PA was broken by that time, though. So, on the RX exercise was on my mind.
The basic antenna switch approach was inspired by this link. These guys are great overall and I grabbed quit a few ideas from them, including the approach the 40m 4-ele OWA Yagi.
S57RR - you are forever in my heart 🙂
Bert’s antenna:
Pay attention to other key Q65a settings below:
- Submode
- RX frequency
- Max drift
- Ftol
As one can see, I had decoded Bert’s signal for about 1/2 hour. So, the Moon was from 8-10 deg to 3-5 deg during this time. My 6m OWA 7-ele Yagi is 12m – i.e., 2λ above the ground. It defines the highest expected angle of the main beam.
Funnily, I monitored the Moon from my window in Almaty apartment on the 12th floor, though the real action – where my QTH is located – was about 50 km from me – on the farm. It was a remote operation.
Key starting links
- https://www.on4kst.org/chat/index.php – the chat to arrange the QSO (or its attempt) and valuable advice about WSJT settings, which and many, to ask
- https://www.bigskyspaces.com/w7gj/Q65SETUP.pdf – Q65 setup. But I was helped in the chat above
- https://wsjt.sourceforge.io/Q65_Quick_Start.pdf – another master guiding document
WSJT settings that worked for me
I acted as a monkey and set what I was told to set based on the advice from helping hams from the chat:
- Q65 pileup – no idea why it is required
- Most sensitive
I set Decode after EME delay – as I was asked.
