For successful moonbounce, EME, earth-moon-earth communications an antenna of sufficient size is desirable. The moon is a long way away. Like 250 million miles or something. Light, and therefore radio signals, take about 2 seconds to travel to the moon and then back again. The Moon does make a radio reflector but it isn’t great.

One could of course question “WHY?” well because it’s there? Or because it’s hard to do. Or perhaps simply because I am a complete and utter nutcase. Take your pick, I don’t really care much!

If you intend to talk to half the world1 via the moon then it is best if you can start by being able to hear one’s own reflections off The Moon. There are fancy pants sums that can tell you just how big an antenna, power amplifier and low noise receive system will be certain of doing this. However, I just cheated and looked at other people around the world and determined that 400W, a 3M dish and a NF of about 0.5db should do it and with just enough margin to be sure.

So, here we have the start of my 3M dish project.

A jig is perhaps not a bad idea.

Yup, that kinda works

3M isn’t that big, I mean, it’s only just a little bit bigger than me

The dish needs a hub to hold all them ribs together. I am perhaps over-engineering this, but I can promise it will be solid.

Rotary mill table seems to be doing the job

Swarf generation

There, the slots are deep enough, next job is to widen them.

  1. OK, so the number of EME stations across the globe isn’t huge. But they do exist on most continents.

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