Can average citizen communitcate with Proxima Centauri? [duplicate]

Question

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• How far away would an alien civilization need to be for us to not notice them? 6 answers

So, we found out there is habitable planet orbiting around Proxima Centauri. Just 4 light years away. Hooray!

But, puts tinfoil hat on, what is still being hidden is, that there is intelligent race living on that planet and it is broadcasting usual broadcasts (as we are). But no one is listening.

So, I want to change the "listening" part. Am I able to pull it off?

• Budget: 10 000 Euro
• Area: I have 10 000 squate metres area of land to build on
• Power possibilities: Usual power plug, or 380 V plug, maximum throughput 50 Amp

Put away question "how are you going to hide the fact that you have huge satellite dish on your backyard"

Other than that, can I plausibly build satellite dish big enough to communicate with nearest star?

By communication I mean at least listening as bare minimum. But I would like to send a message if possible

Answer 1

A few seconds per day, a few days per year

The biggest problem you have is that you are sitting on this huge Merry-Go-Round called the Earth. And this fun-park ride does not only rotate, it also tilts.

Sure, building reflectors out of wood, masonite and a reflective metal sheet is no big problem. And for about a few seconds per day, for a few days per year, you would be able to get enough of a signal to focus on a receiver antenna suspended above the reflector array, just as with the SETI program that uses signals from the Aricebo Obervatory. Aricebo is 73 000 square meters, you have 100 000 available, so yes, you can get a signal.

By adding motorized pulleys on the suspension towers you can even move the receiver about a bit to increase the time you get a usable signal.

But that is all she wrote, because what you really need is to be able to track your target. This would mean that every reflector element would need to be movable. That instantly causes your cost to shoot up far above your 10 000 EUR budget. With fixed reflectors, you can only get a good signal when the angles to Proxima Centauri are just right.

This would best be around the summer and winter solstices because that is when at least one of the angles is changing the slowest.

Answer 2

It's not only about tracking, which you can't really afford. It's also about signal to noise ratio in area you are building it.

Signal from the stars would be extremely weak. Much weaker than signals from Earth. And in case of near transmissions - signal you want might even be weaker than noise in signal from Earth. That's why radio observatories works best in silence zones. Of course you will not be able to transmit from silence zone. And don't forget that NSA has it's facilities there, too, and for the same reason, so it's unlikely you will be allowed to build such a thing at all there.