First thing is to learn the language. I don't think that any language could be learned from radio broadcasts alone, and I'm pretty skeptical about TV, too. Besides, I suspect that broadcast TV is just a phase we're going through. The inhabitants of a system where we want to make contact might very possibly be too primitive or too advanced to broadcast TV.
A lot depends on what sort of alien I am. Is this a planet of hats where I can pass for local? Am I a race of green-skinned space-aliens? Rubber-forehead aliens? Starfish aliens? The more alien I am the more delicately I'm going to have to make contact.
I start with a survey from orbit, of course. I'm not 100% certain that I'm going to recognise what I need to recognise from up here. Large expanses of artificial light on the the night side are probably settlements, but absence of lights doesn't mean absence of inhabitants. Lots of radio transmission stations tell me that an area is inhabited, but again complete radio silence might mean desolation, low tech, or the use of waveguide communications. I don't know how I will conclusively distinguish, e.g. expanses of forest from plantations of high-tech perennial crops. I'd really like to be able to make out vehicles: how big they are, how fast they move. Anyway, collect data as long as circumstances allow and feed it to planetologists, biologists, geographers, and whatever experts I have.
Coming to 21st-Century Earth? I would certainly pick up the radio and TV broadcast noise some way out, but I think that resolving it into separate signals would actually be rather difficult. Sneaking is probably not practical, and I guess that sending a signal would make me look less threatening, so I'd do that. But I don't expect it to be understood, and I don't expect to get anything useful from the replies.
Lights on the dark side tell me where the centres of habitation are, or rather, where the rich people are. I spot a big city on a coast and scope it by daylight, looking for vehicles. I get supertankers and container ships pretty soon, large passenger jets a bit later. This gives me an idea of the level of technology. I think my geographers warn me that the very uneven pattern of development is a bad sign. I probably overestimate humans' vulnerability to heat; even so, Africa and most of Asia look like dangerous places to land: their under-development is most likely a result of warfare.
Then I pick a few spots for landings. I don't want them either in centres of population or near critical resources, for fear that they would look threatening. Which means that the Baltimore-Boston conurbation is out and so is any bright light in the middle of desert. I want places that are in the well-lit-at-night regions, but not in their vital spots: small cities like Geraldton, Western Australia or Christchurch, New Zealand that look big enough to have community colleges in them, but that are service hubs for agricultural districts, not centres of power, uranium mines, or vital transport nodes. And near these places I land remote-operated vehicles with cameras, microphones, speakers, and visual displays on them. I'd send several, as many as I had crews to operate.
And they'd say "Take me to your linguistics professor!"
— Brett Evill
My SFRPG setting, Flat Black© My posts on SFRPG must not be reproduced beyond the board except with explicit permission from me.
Last edited by Agemegos on Wed Jan 07, 2015 3:54 am, edited 1 time in total.