The hearing test

A couple of emails were received from fellow subscribers interested in 6m Moon-bounce. Two of them are already active on the band, terrestrial, with decent antenna, but neither have tried EME. For a simple reason: a misconception that EME requires a massive stack of long-boom antennas which rotate in both azimuth and elevation plane. Of course – the bigger the better. However, setting up a large antenna in a noisy environment is a waste of time. Equally, a single antenna in a low noise environment may be sufficient for a handful of EME contacts.

The question is: how could you be certain that your location is suitable for a weak signal reception on 6m band? The easiest way to find that out is to arrange a sked with a big gun station and ask him to transmit at your moon rise or moon set. The assumption is that you can rotate your antenna in azimuth plane so you can point the antenna at the moon as it appears on horizon (or disappears at moon set).

This window of opportunity should be enough to see if you can decode those weak moon-bounced signals or not. This is exactly what I did the other day: scheduled a session with Fred, G4BWP. As you can see here, I was able to decode almost every single transmitting sequence.

Of course, some days are better than others, and at times the moon simply refuses to cooperate. Even a couple of decodes would be a sign that at your location is EME possible.

Keep in mind that I am still using just a single 5 element yagi so all this would be more impressive with a 7 or 8 element antenna on a long boom.

Clearly, the biggest hurdle here is stepping out of your comfort zone: writing a polite email to a stranger asking for a favour. Of course it would be expected that you do have some understanding of how the skeds are set, when the moon shows up and disappears at your (and their) location and how to set WSJT-x to decode in Q65-60A mode.

Once the sked is set: make a coffee and glue yourself to the monitor. When the first blue line appears, your heart will beat like crazy – but that’s quite fine.

And the usual disclaimer: EME on 6m is hardly ”stop the press” news. There are a number of Australian amateurs who have been bouncing signals off the moon on this band before, some quite successfully. What is new is this: the weak signal decoding software like WSJT-x is ”getting better” so we can decode even weaker signals buried in noise. At the same time, antenna modelling software is so good that we can squeeze every fraction of a decibel out of short yagi antennas. A combination of the two allows a small pistols to enjoy EME – the ultimate in amateur radio communication.

And here is another EME big gun: Bernie, ZS4TX from South Africa. Thanks to his monster antenna system, last night we completed two way contact bouncing signals off the moon in just 4 minutes. The setup consists of stacks for 6m, 2m and 70cm. Bernie is not just a super cool operator but really the nicest guy you’ll find on any band. If you are to email him, make sure to mention my name!