My Beeline did a great job it just stopped logging positions when my speed exceeded 500m/s (both on the way up and on the way down). The important thing was that it could regain lock quickly and maintain it when conditions allowed. Others were not so lucky which could mean couple things - the units inherently don't work well and/or improper mounting/locating of the unit in the rocket (interference, antenna location, etc).
I didn't have any special equipment, just a Kenwood D7A-g with an aftermarket whip antenna from Amazon. The beeline had its standard wire antenna.
Ummmmm, Did you do an adequate range test before flying? Reason I ask is I have two old D7A(g)'s and the oscillators on both of them have gone out of specification. The APRS receive range I have on 70cm is a couple of blocks. I had purchased a D72A when it was available and was going to use the D7's for backup. I hadn't used them in a long time and did a ground test and then connected them up to a frequency counter when the range test didn't go so well. The TNC's have a tendency to
die out on them too. Kenwood just came out with a high falut'in D-74 which is overkill for tracking. Nice thing though is the cost of a D72A has gone down. You could save up and get one for next time or at least see if you can borrow one from another flier. You need a rock steady reliable ground receive station to track your projects of this caliber. I have had nothing but perfect service with my D72. In fact two of us show up with them and he watches
distance and direction on a map and I can have mine set to monitor the GPS altitude for direct rate of descent.
I got a couple of these antennas:
https://www.linxtechnologies.com/resources/data-guides/ant-433-cw-qw.pdf One tunes to the center frequency 433Mhz and you'd get the most of your signal out.
I will relate on a modest note I did a ground test with an 900Mhz NMEA tracker (EggFinder) mounted in a nosecone with the whole assembly on a tabletop chimney of a single story house. I still was receiving a strong signal from 1/4 mile with a lot
of obstructions and called it a good test. Flew it to a measly 3200' and I "underdosed" the motor ejection charge. I won't go into that except an electronic ematch/canister test was successful so I used less powder .9gm as opposed to the 1.3gm in the
motor reload. The motor ejection charge blew but failed to break the shearpins this time. Rocket went in ballistic. It was entirely sight unseen except when it was 40 feet up, I heard a beep on my receiver and got a datapoint/icon on my live map that
was north of the launchpad.
I have two possibilities and one might apply to your situation. The black profusion nosecone attenuated the signal. Maybe that's the case but I believe I had a decent ground test.
The other is that the GPS, in my case a Sirf IV chipset doesn't do well in a high dynamic state. It did get "one" maybe two packets out before it hit. That's how I was able to dig the rocket out, replace the nosecone (I broke it digging it out of the clay).
Just took that one or two packets and I walked to the point on the map. Next flight with a thin-walled red nosecone that is translucent enough to see the GPS tracker led's flashing through had a derned forward closure failure with the rocket
getting about 3-400 feet up. Two flame jets, one at the bottom, one out the side is not a good sign. Rocket flopped around and again, I received positions on the pad, 20 or 30 feet up and then when the rocket was flopping around for several seconds,
nothing. The charge blew (successfully I might add), the Jolly Logic Chute Release released the chute but the rocket wasn't high enough for it to inflate. No problem, soft farm ground saved the day though I thought the rocket was trashed and was going to gut it for the retainer and save the nosecone. It's a glass rocket and after I looked at the kevlar cord with a bore scope I saw it was intact as the flame burned out the other side. I had a shockcord protector and made a sleeve of boric acid/borate soaked cardboard that I put over the shockcord protector. Saved the kevlar really well. Just slid and epoxied a glass coupler down the tube to cover the hole and by golly it will fly again.
What this suggests to me is if the rocket goes ballistic or unstable, a GPS tracker might not work optimally. At what point of the descent did you start to receive positions again on descent Kip? Kurt
