GrouchoDuke said:
Eggfinder fits, but not in a coupler - only in a body tube. I'm using a Ready To Fly Quads Micro M8N gps tied to a TBeacon for my 29mm.
Can you post a picture of this setup?
I don't have it assembled right now, but here are some shots of the 3d modelling I did for the 3d printed sled. This isn't the final sled design, but it should get the general idea across. I'm putting this in a 3" long coupler tube. Not shown is where the switch goes. I'm using a Featherweight magnetic switch that's strapped to the battery. The other component on the drawings is an Altus Metrum EasyMini. The battery is a 1S 150mAh LiPo from Adafruit. The main problem I had fitting things in was that I wanted to fit a GPS tracker along with a commercially available altimeter. A lot of the "fits in a coupler tube" components won't fit when they're stacked in there with something else.
I haven't flown the TBeacon on a rocket yet, so I can't vouch for it completely. My first flight with it will be about a motor that'll make the rocket pull about 70g, so that should give it a fairly good first test. You can program the TBeacon to talk on the FRS radio freqs, so (if you pick the right freq) it wouldn't require a ham license. To get better range than an FRS radio, I'm using it on a ham freq with a cheap handheld ham radio. It's not telemetry like the Eggfinder or TeleGPS. The TBeacon listens to a GPS signal and reads the coordinates to you (i.e. a voice transmission) when you send the TBeacon a tone. It'll require a little more thought, pre-planning and real-time execution than any of the telemetry solutions would require. I went with it because I wanted a tracker that gave me GPS coordinates it and I wanted it to fit inside the coupler tube along with the altimeter (the tube has an ID of about 25.5mm).
It was designed to survive r/c aircraft crashes, but I'm not sure how those compare to the 70-100g launches that a 29mm min-diameter rocket can do. There are some YouTube videos on it if you'd like to see it in action. Airborne range should be way plenty, so I was hoping to get coordinates from it while the rocket was under the chute. Those should get me close enough to get updated coordinates from it once it's on the ground.
If the weather cooperates, I plan to fly my 29MD rocket with the TBeacon for the first time next weekend. I'll let you know how it goes.
I know there are some LoRa trackers in development for r/c aircraft and balloons. Those should have huge range and provide telemetry throughout the flight. You could build your own one of those, but I don't think there are any of the shelf ones you can get yet. I looked at coding one up using an Adafruit Feather with the RFM95 ($35!), but it's a little too big to fit in my coupler tube too. I haven't heard of any LoRa trackers targeted for rockets. A tiny Ublox 8, LoRa, altimeter, accelerometer, gyro all-in-one unit would be great to have.
The TBeacon has been talked about here at least one other time. There are pros and cons to it, but after lots of research it looks like it'll work for me. Quite a few of the "no way, I wouldn't use that because..." comments in the other thread don't apply or have been taken care of through the software design of the TBeacon. Whatever you chose, do your research beforehand. If you don't put things in a coupler, it'll give you more room and open up more options.
If you want to do some direction finding/fox hunting, something like a CSI Locator might work great too.
