For maximum reliability, how about a tracker that does both, like the TeleMetrum? I've been into rocketry for less than a year and am not any kind of expert, but I'm having trouble with the notion that RDF is more reliable. If the rocket lands hard (or in water) and the tracker goes dead, with RDF you are out of luck, you do not have any way to find the rocket. With GPS, you can still find the rocket because you'll have the position a second or two before impact. That happened to me a few months ago -- my Chute Release failed to release the chute and the Telemetrum turned off as soon as the rocket hit the ground. As the attached map shows, I could still see where the rocket landed.
Many have been there and done that too with a GPS tracker including myself. I didn't have a long walk but I didn't see where the rocket went in. It was straight out in front of me as indicated on the live map I use to track. Walked out to it and just made my local position on the map intersect with the rocket's fincan sticking out of the ground With RDF, unless one can hold the bearing, they are S.O.L for a longer recovery. If there is the room, one can fly two trackers one GPS one RDF for redundancy.
900Mhz doesn't lend itself for RDF tracking anyways for several reasons so no one should go in with the thought they can RDF a 900Mhz tracker.
Here is another plus for Ham Radio APRS (besides being "record" getting ready with the
Beeline GPS's). With the 70cm and 2 meter band trackers as long as one gets a carrier signal, in a pinch one can RDF to a GPS tracker as long as it's beaconing. If one's APRS GPS tracker can be set to beacon no matter what, the option is there to RDF it as long as it's sending
I have to admit though with the dozen Beeline GPS flights I've had to sight unseen land, even though I have the ability onsite to RDF 70cm and 2 meters, I've never had to do it.
A simple Marvin West Attenuator can do both bands:
https://www.west.net/~marvin/k0ov.htm Be careful to "shut off" the push to talk switch (in the programming screen) in the H/T when using an electronic attenuator or you'll kill it. Get a Ham license and pickup
a Beeline RDF tracker on 70cm and get an H/T (handi-talkie) with a true signal strength meter. Yagi antenna, homemade or otherwise with the simple electronic attenuator and
one will be in business. I've tested out the Beeline RDF's with the above setup and it
works as well as the overpriced commercial animal trackers. Invest in a Kenwood D-72A
and you'll be able to do APRS tracking from the 72, from the 72 and an attached Garmin Mapping GPS or from the 72 and a Windoze or Linux tablet. Get a 70cm RDF tracker and the 72 is perfect.
Gotta kill another hour and half before Midnight Mass for Christmas. Hope everyone gets what they want, have a Merry Christmas and a Happy Fly'in New Year.
Oh, I got what I wanted. Had to "pass" a do or die recertification exam which everyone walked out of (including me) thinking they flunked it. I made it with room to spare so I be
really glad. Found out last Thursday and been sweating it since November 9th when I took it.
Kurt