This project hasnt really begun in earnest yet. What I am hoping to do is use three old TV satellite dishes as an interferometer.

The basic idea is that by pointing two dishes in the same direction, I not only can increase my ability to receive my signals, but I can also remove noise, by mixing the signals from both dishes together. Noise, having no, or random, phase, will cancel out, wheras real signals will re-enforce and come out stronger

One problem is that in order to get a directional enough signal from such a small dish, I will have to use a very high frequency. This isnt hard, since the dishes naturally work at ~10GHz in their normal function, so the antenna amplifier is certainly up to the job. However, at these frequencies, the signals are difficult to work with

Normally TV dishes 'down convert' the signals they receive to about 1GHz, which is much easier to shove down coax cable without horrendous losses. however, this poses another problem in my two dish setup, since the 'local oscilators' in each dish are not synchronised, and so will naturally run out of phase (or even at (slightly) different frequencies altogether). This would mean that the signals I would hope to mix together would actually be of different frequency 'bands', which is useless.

The solution I have chosen, is to destroy the local oscilator in the dishes, and feed the full 10GHz signal down the line. The losses will be acceptable because the dishes will only be a few metres apart, and so I can achieve mixing my simply shoring the two dish outputs and tapping the exact centre of the line. At the tap, I will place another LNB (the head of the dish), with the antenna removed, and use it as a down-converter for the now mixed signal. This signal will be the one fed into my radio receiver and then on into my PCs soundcard.

Well, thats the theory. I also have to work out how to power the dish-heads and actually built the dish mounts too. Watch this space.