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All things pertaining to wireless and RF links
By Ashaman0
#64807
Im looking for some advice on a long rand wireless solution. I have a glider which I have been dropping from a whether balloon and I am looking to add a wireless link to the plane so I can track its movements from my laptop on the way up and on the way down. Currently it just stores all its gps and sensor data on a little microsd card and I can look through it when I get it back. Does anyone know how big of a project this would be. Ive dropped from heights up to 60k feet, so the radio would need to be capable of LOS communication up to about 20-30 miles as the balloon is blown of course.

Im just curious on how much work this would be and what type of equiptment I would need. Thanks!
By stevech
#64882
Ashaman0 wrote:Im looking for some advice on a long rand wireless solution. I have a glider which I have been dropping from a whether balloon and I am looking to add a wireless link to the plane so I can track its movements from my laptop on the way up and on the way down. Currently it just stores all its gps and sensor data on a little microsd card and I can look through it when I get it back. Does anyone know how big of a project this would be. Ive dropped from heights up to 60k feet, so the radio would need to be capable of LOS communication up to about 20-30 miles as the balloon is blown of course.

Im just curious on how much work this would be and what type of equiptment I would need. Thanks!
I work in wireless and I don't know of an unlicensed band you can use for 20-30 miles.

If your operations are in an area with ubiquituous cellular data coverage, you can likely purchase a GPRS or 1XRTT modem approved for use on AT&T, T-Mobile (GPRS) or Verizon (1XRTT). Not sure they'd work at 60K ft. up though. 1XRTT is more likely than GPRS. Youd arrange the balloon side to send to an internet address to reach your ground side. Or do an SMS message to your cell phone with GPS coordinates.

902-928MHz in the US is unlicensed and you can emit several watts on the balloon. Until it gets too low, a good receiver and a long yagi antenna (available commercially) might get you 15 miles. If you can point the Yagi correctly.

Also, terrain may come in to play in hilly areas, when the balloon goes below earth's curature defined horizon, minus any hills. Not so with a cellular phone approach, if there's cell coverage.

Thinking aloud, there's the MURS VHF band intended for unlicensed maritime use. It might get the range until below say 1000 ft. There are a few modems for MURS you can buy.

And ham radio (simple license needed). On 2M or 6M.

For $$ you can use ORBCOMM (google that). But the radios are big.
By Symmetry TME
#67176
I agree that using some kind of Cellular modem would probably be your best bet here.

Here is a link to a GPS/GPRS module from Telit:http://www.semiconductorstore.com/cart/ ... duct=42894

I am familiar with these as I am an apps engineer specializing in Telit's modules.

I agree that the height might be a problem, but with a preloaded Python script (available with Telit), you could collect the GPS data and send it once a GPRS connection was available.

Good luck!

-Brian