Ham Radio/Long distance two-way radio
I’m a science fiction writer, with little or no expertise with radios, to be blunt. I’m writing a story about a person who acquires the ability to journey through space; long story, but hey, its science fiction :). At this stage of the story he wants to keep his capabilities secret—from everyone except a few trusted friends.
Shortly after he “acquires” this ability, he and these close pals want to set up a communication system, with one “station” here on earth and the other on our moon (he can travel there, they cannot). I’m thinking a pressurized module set up on the moon; pressurized because of the vacuum, with a diesel generator for power.
Now for the radio. I was told that radio waves travel easily through space and a 5 watt transmitter thing would be sufficient, even for the 240,000 mile distance. Of course, while the module/cabin is always facing the earth on the moon’s near side, the earth is always rotating so they could only communicate when the earth site is in view from the moon. NASA used relay satellites, and stations, I heard.
One of the protagonist’s pals I have as a ham, who sets up the two-way. Strictly off-the-shelf, to keep the secret from prying eyes. Although maybe the main character could get some gear from NASA, employing a 5 finger discount ;). Unfortunately I know nothing and was hoping you would share how you would set up both ends. The more specific the better. Make, model, etc.
Any help would be much appreciated.
First of all, a diesel generator would use a huge amount of air and a cooling system without air would be gigantic. Time to think solar power.
Yes, radio waves propagate very easily through space, and yes, you could theoretically do it with 5 watts with a proper antenna. The antenna has to be very directional, a narrow beam, as it were. Using a couple hundred watts would be more practical. UHF and VHF frequencies would be most appropriate as they are line of sight.
There is a sub-hobby of Ham radio called EME (Earth-Moon-Earth) or Moonbounce. Signals are bounced off the moon, back to earth. This is harder to do than if there were transceivers on both ends since the bounced signal is so scattered. High power, great antennas and very sensitive receivers are helpful. With transceivers on both ends, things get much easier.
Here's a link to a good description of EME...