Radio Free Luna

[kengr]

Radio Free Luna is a concept I've seen in several stories and at least one filk song.

Basically, a radio station broadcasting from the moon and doing programming that some places on Earth might not approve of. For example at the moment, actual reporting on the war in the Ukraine beamed at Russia.

Simple enough concept. The biggie being having folks on the moon long term who aren't all that dependent on Earth and it not being worth the effort to stop them.

But I'm wondering about the practicalities. Power is easy enough large solar arrays and lots of storage for he night.

Antennas are another matter. Anybody have suggestions? Would beam antennas on nearside/farside boundaries be better? Or would some sort of centrally located antenna?

I'm thinking short wave or maybe even AM or FM bands. Just not sure what would be the best combo for both reaching more radios and best penetrating the ionisphere.

At least you can build *big* on Luna. Full wave dipoles anyone? :-)

Comments

[stickmaker]

Didn't Heinlein have a Radio Free Luna in _The Moon is a Harsh Mistress_? Though that was an organ of propaganda for the lunar government, IIRC.

Not sure about antenna location. At first guess, I'd say put the antenna and final amplifiers (you wouldn't need to have the actual station in the same location) in the center of the nearside. Of course, you'd want to choose a location to maximize the period of daylight for solar power. Since the antenna would still be facing the Earth even during lunar night, you'd want to have an alternate source of power. Maybe just a large set of batteries.

Would have to check on which frequencies would penetrate best. Shortwave works by bouncing off the ionosphere, so it's probably out.

For the shape, emulate Arecibo and that Chinese radio telescope and string cables from the rim of a crater.

[kengr]

Well, a "dish" might not be needed at the relevant frequencies. Also given the size of the target, not a lot of focusing is needed.

As for the finals, being in a fair vacuum is helpful. You can make *monstrous* tubes, and it's fairly easy to "pump" them to a good vacuum. Also you don't need strong walls as the pressure difference between inside and outside is fairly trivial in terms of loading forces.

Probably need more reinforcement to protect from micrometeorites and idiots running into them.

A multi-megawatt (gigawatt?) tube will be a sight to see.

[stickmaker]

Oh! And don't forget about building vacuum tubes as big as you want without worrying about pumping them down. Just remember to shield them from dust...

[kengr]

Yeah, but the vacuum on the moon is only so-so, especially near anything humans will be living or working in. Probably still need containment and some "flushing".

Which reminds me, I recall plans from an old (early 60s) electronics magazine for turning an old transmitter tube (the size of a 2 liter bottle) into a table lamp. :-)

I also recall some old (50s & 60s) SF novels that had ham radio operators on Luna making their own tubes.

[siliconshaman]

You don't need people on the Moon... what you'd need is a repeater station, and a very tight beam uplink from someplace out in international waters, or rather several somewheres. Or if you really don't want people knowing where you're transmitting from, then use a laser uplink to the Lunar transmitter array from some orbital satellites and tight beam microwave link from multiple ground stations. It wouldn't look unusual for a encrypted uplink to a satellite, and the laser relay link wouldn't even be visible from Earth.

Come to think of it... you wouldn't even need that big of a satellite, a 20x20x30 cube-sat would do it as the orbital relay. How you'd get the radio transmitter array on the moon I'm not sure, but given that Space-X is planning on doing ride-shares on their moon shots for private firms, it's not beyond the bounds of possibility.

[kengr]

Given the amount of construction (and maintenance) likely required, a lunar base is probably easier.

Hmmm. I know treaties say that Luna can't be claimed by a nation. I wonder what they say about claiming *part* of it? Much less a lunar base or colony declaring itself an independent state?

Then again, if it's an alternate timeline, they may have been there *before* the treaty. :-)

An "educational" channel giving info about various parts of the moon might be popular. Especially if there's an observatory at Farside base.

A large mirror array would be fairly easy to build (assuming you have the people and tech to build things on the moon in the first place). And a multi kilometer radio dish in a crater ought to be doable as well.