Communications System Help Wanted

Communications System Help Wanted

Postby Monroe » Fri Oct 23, 2009 11:33 am

Team Prometheus wants help with a reliable communications system that can stream video (HD) and data from a rocket launched from 100k/ft. (live like falcon 1 did) And it needs to be affordable or scratch built and of course small. We are not talking toys here or Dreams something that really works!

Monroe
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Re: Communications System Help Wanted

Postby rick m » Sat Oct 24, 2009 3:04 pm

Hi Monroe,
You might want to talk to Richard about this if you get not other responses. We are planning on having our stuff sent down real time (telemetry). I believe it's scratch built, and is designed for the vaccum of space and I think able to take 35 G (don't quote me on this as I'm on the propulsion, assembly, launch, and recovery teams). I'm not sure if it would be "affordable" but I do know it's not a toy or dream. I will know more after I get briefed on the avionics.
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Re: Communications System Help Wanted

Postby MisterQED » Mon Oct 26, 2009 5:59 pm

As has been mentioned before, legalities are the issue. Falcon 1 probably used a space based data relay which transfers all the legal headaches to the relay holder.
As I assume those options are not available to you, and Ham bands are not available for what we all hope is a profit making venture, you are left with few options.
The unlicensed bands are the easiest and of those the one with the most tested equipment on it is 2.5GHz, the WiFi frequencies.
I'd suggest using two radios, something like 900MHz for a telemetry feed and then getting a BIG dish created or converted for use on 2.5Ghz that tracks based on the telemetry stream and you should be able to get HD video.

http://www.engadget.com/2005/11/15/how-to-build-a-wifi-biquad-dish-antenna/

The link on the page goes to a site discussing the world record 125 mile WiFi link.

Since the antenna on the rocket will be small, I'd suggest you use on of the 12' jobs on the ground with circular polarization.
Or if you have the cash: http://www.radiolabs.com/products/antennas/2.4gig/stage6.php
The big problems are tracking with the dish and making a decent antenna on the rocket.
The tracking is just a problem of stepper motors, linear actuators, accurate GPS data for sender and receiver and programming.
The rocket antenna issue was just discussed on arocket within the last month and the consensus seemed to be "patch" antennas.
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Re: Communications System Help Wanted

Postby Monroe » Mon Nov 02, 2009 5:06 am

QED
Well we are looking at tracking the rocket with a guidescope that tracks the rocket using the inverse method compaired to a normal guidescope. Normally the "guidescope" tracks a star to guide a telescope (not usually the one the scope is looking at either) This scope looks for the dark spot the rocket makes and tracks that instead. This in turn guides the dish.
I have seen nothing that works right yet in the amateur rocket guys even arocket they just don't go high fast and far like we will. We don't even have communications live from a balloon much less a rocket! Damn this is slowing us down! People talk about this and that but none of it really works yet!
Maybe Richard and SS2S Will end up helping us yet! I hope they get something working!

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Re: Communications System Help Wanted

Postby rick m » Mon Nov 02, 2009 6:39 am

"I hope they get something working!"
Our first flight test is planned for February.
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Re: Communications System Help Wanted

Postby Monroe » Tue Nov 03, 2009 3:51 pm

Rick
I'm making some parts for you right now ;) Richard asked for some pictures. Will be watching the avionics to see how that goes.
Good Luck & Godspeed SS2S
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