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[ADAMJG]

Hi,

I am into amateur rocketry. What I am working on is producing a payload with onboard GPS that will transmit position/altitude data (or all NMEA data) back to a mobile base station 3 miles away, allowing the rocket to be located.

The Motorola Oncore GT Plus embedded GPS receiver ( http://www.synergy-gps.com/bgt.pdf ) looks like a good option to me. My problem is transmitting its serial TTL NMEA output. What should I use? Should I be looking at something like this: http://www.orbitcoms.com/Wireless_modules/FM_Wireless_Transmitters_150MHz.htm ?

Am I able to simply broadcast this data and read it at the base station, or will the link need to be 2-way?

If you are wondering about what other equipment I have, the answer is none... other than a simple Uniden scanner. Thanks for any help anyone may be able to give, and Merry Christmas.

Adam

[KG4RUL]

First off, you do not indicate whether you are a licensed Amateur operator.  This will greatly influence what frequencies you will be able to operate on.

 
The transmitter you are looking at is FM with Frequency Shift Keying (FSK).  You would need additional equipment in the form of a Terminal Node Controller (TNC) and a computer to use with your scanner.  If you are on the Amateur bands, you will need a means to ID the transmissions periodically.

 
The best solution, providing you have at least a Technician class license, may be to use Automatic Position Reporting System (APRS) equipment. This could be accomplished by using a device like the Tiny Tracker along with a low-power FM transmitter (Vectronics).  


The Tiny Tracker provdes an interface from the GPS to the transmitter and can be programmed to provide the necessary ID.  Many APRS programs are availabe for use with a computer.  The computer, with a suitable sound card, can also handle the functions of the TNC and eliminate one more piece of gear at the receiving end.


Dennis - KG4RUL

[ANULLRETENTIVE]

If you don't have your Ham license you can still transmit your data using the new MURS radios with a couple of watts, license free.
 http://www.teledesignsystems.com/downloads/ts4000/Apps/Unlicensed%20VHF.pdf

Tiny Track modules to interface the data can be found at www.byonics.com

MURS radios can be bought at Radio shack.