Bouncing Signals Off The Moon
One of the great things about ham radio is that isn’t just one hobby. Some people like to chit chat, some like to work foreign countries, some prepare for emergencies, and there are several space-related activities. There are hundreds of different kinds of activities to choose from. Just one is moonbounce, and [Ham Radio DX] decided to replicate a feat many hams have done over the years: communicate with someone far away by bouncing signals from the moon.
The set up is pretty sophisticated but not as bad as you might imagine. You can see that they spend a lot of time getting the equipment aligned. A known reference point helps them set the position of the antenna. A GPS keeps both stations in sync for frequency and time.
Some of the gear is repurposed commercial gear. A standard transceiver generates the signal, but not at 10 GHz. A transverter and a 60W amplifier put out a relatively strong signal at 10 GHz.
As far as we know, the first proposal for bouncing a signal off the moon came back in 1940. The military and a Hungarian group were the first to pull it off in early 1946. Remember, with no satellites, having a direct teletype link between Pearl Harbor and Washington DC was an amazing achievement.
Ham radio operators starting using moon bounce (sometimes called Earth Moon Earth or EME) back in 1953. The round trip propagation time is about 2.5 seconds or so. In this case the stations used WSJT, a computer program made for weak signal work.