Rocket tracking with GPS enabled FRS radios

I was thinking about investing in some tracking hardware and after looking at the usual suspects - Rockethunter, Walston, Big Red Bee - I came across some Garmin GPS enabled FRS radios. The cool thing is they will send their location out when the mic is keyed, or on some models you can request the location of a remote radio.

I was wondering, has anyone tried using this kind of radio, and if so how accurate were they?

Oh wow, that is soooo frelling cool! Especially the Position Reporting function that shows graphically on one radio the position of the other(s). That would take all the fun out of hunting for lost rockets though, wouldn't it?


person who has lost rockets -> :kill: <- me

One of the members of our club did that. He used the Rhino 110 and built a add on board to trigger the radio. I know his first attempt was unsuccessful but it had something to do with the radio getting turned off on launch. I am pretty sure he solved that and got it to work but I don't know all the particulars. If Troj sees this thread he can probably provide more info.

Garmin is based here in the KC area (Olathe, Kansas), so I'm always happy to see their name mentioned.

The Rino 110 weighs 7.6 ounces and will run the GPS and radio for 14 hours on 3 AA batteries. You could substitute Li-Po for the alkaline batteries and cut the weight by 2 ounces. The spec sheet says it's 2.3" wide by 1.7" deep. You'd probably want a 3" body tube to leave room for some padding. I'd want to beef up the battery holder (or go with external, soldered battery connections) to prevent loss of power at launch due to batteries compressing their little springs. Otherwise, the thing looks like it's built like a tank.

As mentioned, you would need an external circuit to key the Push-To-Talk function via the external microphone jack. It sends its location when the button is released, so a timer that closed a reed relay for a second then released for thirty seconds would do fine. You can only send position reports every 30 seconds (FCC rule), so using this for real-time flight profiling is out. The Rino DOES store the track internally, so you download the profile after you've recovered the unit.

The tracking radio stores the last received fix, so even if the radio does not survive the touchdown, you'll have some idea where it's at.

Garmin just updated the firmware so that position can be reported on GMRS frequencies instead of only on FRS. This will double the tracking range. You DO have a GMRS license, don't you?

Hope this doesn't sound like I have experience with these little jewels. I'm just perusing the docs on Garmin's site. Gotta cheer for the hometown team!

Oh yeah, these are going for around $145 each.

Rick
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