Can I use the moon as a passive radio satellite?

Question

Can I use the moon to reflect my own radio signals so that I can communicate via radio on the other side of the earth? What kind of frequencies do you think would be the most efficient?

Could it be done by an individual?

Answer 1

Yes you can. Back in the 1960s when I was at high school and knew more about radio than I do now, because brain cells die, and we didn't have amateur radio satellites, we used to communicate on around 432 MHz using the Moon as a reflector. Of course, your signal has to make a round trip to the Moon before the other guy hears it, and similarly for his reply. So it's several seconds before you get a reply. So you include in the message the word moonbounce. A message reflected from a distant lump of rock weakens according to the radar equation. The reflected signal your correspondent receives goes down as the fourth power of the distance of the reflector. Also, the Moon, being a dry non-conducting lump of rock, isn't a good reflector, so both of you will need very, very sensitive receivers. And of course the Moon will need to be above the horizon for both of you.

Answer 2

Signals can, and have, been "bounced" from the moon back to Earth. Even though it does make a very poor reflector, the sheer "wow factor" of a successful signal bounce easily forgives the quality and makes the effort quite worthwhile, in my opinion.

However, if you use this method to "communicate via radio on the other side of the Earth", then your signal will be broadcast almost tangent to Earth's surface when the moon is at the horizon, forcing it to pass through a very thick layer of atmosphere at a minimal angle, subjecting it to a great deal of signal loss. The return signal would likewise need to re-enter the atmosphere at a similarly shallow angle. Prepare for a very weak and noisy signal.

Answer 3

Yes, I've done it, it sounds totally awesome to hear your voice after a 500k mile round trip. For best results, VHF frequencies or higher need to be used, along with several antennas with exceptionally high gain. Also, a very powerful transmitter/amplifier and very sensitive receiver are required.

Hams have been using this method for over 60 yrs, ever since the US Army bounced a radar signal off the moon 60+ yrs ago.

Answer 4

yes definitely, longer waves mask the uneven surface reflection problems but are weak and lossy. Shorter waves (higher frequencies) even up past micro wave and into lasers are more efficient but harder to predict and the moutains and craters reflect them all over making it hard to get your transmission to any specific area on earth. If you have a directional antenna with high gain you can dx the moon. have fun. look in ARRL handbooks about ten to fifteen years ago. you will likely need to make your own antennas and wave guides for this. The satellites are harder to see but are much easier to bounce the signal from. If you want there are satellite channels available for amateur use as repeater stations.

Answer 5

It's been done. But the moon is a bad reflector of RF energy and at a goodly distance, so it takes a powerful transmitter, large antennas, and a good receiver to pull it off.

Answer 6

Well, i suppose you could do this, theoretically. I've read of it somewhere. I really have no idea how you might do this. i would imagine it would require a very long wavelength to be accomplished.

Check out the ARRL handbook - that might have some good information on it. You may be able to do it as an individual, but i make no guarentees.

Answer 7

Not without a reciever and transmitter on the moon. As the moon's surface is uneven and not calibrated to "reflect" signal waves, you wouldn't get anywhere.

Answer 8

nope