Few questions:
Was this a first flight of the system?
Were you receiving streaming positions during any portion of the flight? If so, you should have seen a few on the map. When the rocket settles down under the main, position reception should be better. At 4k' altitude is your friend for propagation. If you got nothing after the main fired, something broke both trackers. That is if you had a well operating system. Was it a main at a low energy apogee or was it a main on ascent? If it was a low energy deployment then the following questions have relevance. If it was deployed under a high energy condition then the deceleration forces would come into play. You did say a main at 4k' so it sounds like a low energy deployment.
Did you do a ground range test? Set the rocket up transmitting in an open field and walk away from it with your receiver to see what range you get?
How were the trackers secured? Nose bay? Riding with the altimeters? Riding in a hardened container on the apogee harness?
Metallic painted rocket?
Were the trackers in a carbon fiber tube?
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Some responses:
Ground testing is very important to troubleshoot any potential problems. If not done satisfactorily, the failure causation is pure conjecture.
If the trackers broke loose, lost battery power or broke their antennas they aren't going to have any range if they are not working.
Metallic paint can attenuate Rf and lead to lousy range. That is frequency dependent. Some trackers one might get away with it, some not.
Ground test to find out. (Or avoid metallics on Rf bays as I learned to do!)
Carbon fiber tubes attenuate Rf. If the tubes are made out of that stuff, all bets are off and the tracker(s) should reside in a radiolucent non-metallic painted fiberglass nosecone.
I believe it all boils down to a good ground range test before flying to be certain the base setup is competent to fly. One may see positions streaming in on the pad but once in the air nothing is seen. Another trick with a new system/rocket is use a lower powered motor that you know is likely going to keep the rocket within visual range. If something goes awry, a visual recovery is assured and one gets a second chance to trouble shoot the system.
It remains Bill you had a backup tracker and had a failure of both. That is a really tough failure and sorry about your loss. I hate when that happens, especially
when it leaves one in a tough position trying to figure out what went wrong.
I've used a couple of instances of
APRSISCE/32 to track rockets by feeding the raw NMEA strings through the base station GPS port. A second instance will keep track of my local GPS position for monitoring recovery to the recovery site. The second instance runs in the background and uses an internal network port to paint the local position on the rocket map. The advantage of the Ham software is bread crumbing of positions will be saved on the map. Every position gets its own "dot"and the lines connect the dots. One doesn't have to worry about writing down or finding the last position as it's always painted.
I had a small size, apogee only fiberglass rocket lawn dart with an Eggfinder in the nosecone. I saw two positions on the map. One the launchpad and one out in the field. I belatedly went to the position out in the field and there was the fincan sticking out of the ground. New nosecone, new EggFinder and it's flying fine now. BTW, I've made some of those mistakes I allude to above. Also, I still haven't found the perfect program to NMEA track rockets. In the Ham band the APRS trackers and APRS tracking programs work very well without any sleight of hand. All the best, Kurt Savegnago
