Last updated 2001-01-23

I'm slowly working at building a decent EME (earth-moon-earth) station for the 144 MHz band. There's still a lot of work to do, but around 10 tonnes of concrete is already in the ground and the bottom section of the tower has already been assembled.

If you don't happen to be a nutcase with a working knowledge of EME, you might wonder what this pastime is all about. The basic idea is to use the moon as a reflector to allow communications between two stations far apart, even though the frequency used normally would not support communications between those two stations. With the Internet and international direct dialling, it's clearly not necessary to bounce puny-weak signals off the moon to communicate. However, EME is a supreme technical challenge. The fraction of transmitted power that returns to earth is miniscule, and such signals are extremely weak. To get a grasp of the fraction involved, try to imagine the size of a gnat relative to the size of the earth, and you're in the right ballpark!

Very strong transmitted signals and a very sensitive receiver are required, and big antennas are the order of the day. Apart from the obvious electronics work, there is also a lot of mechanical work involved, to make sure that the antenna can track the moon sufficiently accurately to stay in its very sharp beam.

There is also another aspect of challenge to the whole thing: Securing all the necessary materials without spending more than you have! Fortunately, over the past years, the likes of Jan van Niekerk ZS6NW, Bernie van der Walt ZS4TX and Greg Smith ZS5K have made tower hardware available at prices that I couldn't refuse. However, even collecting towers from far-away cities is not always simple, as you can see by looking at one of my trailer's wheels after collecting a tower from 600 km away! Things like towers, feedlines, antennas and amplifiers definitely do not fit into my radio budget, so my begging and scrounging skills are well-developed by now.

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