"Open Source" Radio Beacon?

"Open Source" Radio Beacon?

Postby Delta_V » Fri Jul 18, 2014 8:25 pm

There's been a bit of noise about a possible collaborative N-Prize attempt. In this vein, I'ld like to start a topic to throw around some ideas dealing with orbit validation, so we can build upon each other's creativity and experience.

Assuming that a radio beacon of one form or another is best for validation (some people have suggested something visual, but that requires orders of magnitude more power), and seeing that some of the more advanced teams have even built and tested some transmitters, perhaps this part of the design would be a good place to start with collaboration. I'm assuming that orbit validation would be the area with the least difference of opinion, as opposed to say, propulsion, etc.

So if anyone has any ideas, no matter how developed or not, dealing with orbital validation in the form of RF signals, this is the place to post. Anything from general ideas, to electrical schematics, to mechanical issues. Hopefully we can get some sort of active and productive conversation going, and start a team design effort of some vague sort...
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Re: "Open Source" Radio Beacon?

Postby rick m » Sun Jul 20, 2014 8:48 am

We've received 10mW beacons from 100,000' and 30 miles away with a simple yagi and could have gone farther.
According to Wikipedia:
The University of Tasmania in Australia with their 26m dish was able to bounce a data signal off the surface of the Moon which was received by a large dish in the Netherlands - Dwingeloo Radio Observatory. The data signal was successfully resolved back to data setting a world record for the lowest power data signal returned from the Moon with a transmit power of 3 milliwatts - about 1,000th of the power of a strong flashlight filament globe.


The key here is the ground receiving antenna ability since the power from a N-Prize sat will also be low. Assuming a low earth orbit (100 miles?), a good Yagi should be able to receive a 10-50 mW transmission provided you know where and when to look. We did receive signals sent from a balloon 70 miles off and 95,000' with 100 mW but that is more power than we were planning on using...so the question is how good is your antenna
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Re: "Open Source" Radio Beacon?

Postby rick m » Sat Aug 30, 2014 4:41 am

While not orbiting in space, this project has launched a tiny payload that has been transmitting successfully for several weeks with the aid of small solar cells:

http://www.theregister.co.uk/2014/08/22/bodnar_b_64/

Well engineered project that just keeps going and going and...

Rick
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