I went to a talk at PAARS by Lars Karlsson, who is a member of a small group of people who have managed to bounce 24 GHz radio signals off the moon and talk to other people. Plenty of people have done this at lower frequencies, but literally only a handful this high.

He built or obtained surplus most of the equipment, as did the people he talked to. Lars used a six-foot 56db gain parabolic dish antenna with a 100 watt transmitter, and a beam width that is slightly less than the width of the moon, so the signal covers most of the moon, except for the edges. The path loss one one way is 296 db! (And you thought T-Mobile's coverage was bad!)

He has talked to people with similar equipment in Russia and Canada. The propagation delay is about 2 seconds.

The signal sounds choppy when it comes back because the moon vibrates up and down slightly and produces to a doppler shift up and down at the same time, but skipping the edges reduces this effect. The rotation of the earth also doppler shifts the frequency, but that is by a consyant amount and doesn't affect the signal quality.

He played a recording and it was barely audible, but definitely there.