Hokay, The 3DR radios are programmable as far as frequency is concerned. Rf messing with deployment electronics is a real though diminishing possibility. Anything by EggTimer has opto-isolation on the deployment side so resistant to Rf interference.
The MARSA is resistant as likely as others are. I've been burned by Rf whacking a P6K, I've seen Adept 22's in a dual installation shutdown by a 2 watt dog tracker and make a rocket go in ballistic and the AIM2 controller specifically states in the
manual it doesn't play well with Rf.
That said, do an all up ground test with contained ematches with all the electronics on and let the rocket sit for 45 minutes to an hour. If the matches don't pop, the deployment devices don't recycle or shut down, you should be good for flight.
Also nose mounting the tracker will help.
500mW at the 70cm band would be good for > 50,000 feet easily depending how good the receive station is.
I ordered a 70cm set and will try to get it going with a small tablet and see if I can get it working with "GPS Rocket Locator" on the Android side. Android is screwy. Plug a dongle in and it will suck the battery life out of your device. Try a Y cable for a Dongle and
you cannot use the Dongle and power the arrangement at the same time. One has to get a program Elemental-X and have a compatible rooted device:
https://elementalx.org/
With this utility you can configure it to connect external power AND a dongle (or memory) at the same time so you don't run out of juice. The trade off is the OTG socket will not be able to read or use memory sticks "without" power attached through a Y cable
anymore. That's acceptable because it's not permanent. One can run the program from TWRP recovery and set it back to "stock". Again this is just supported by the devices listed at elementalx.org and one has to "root" their device.
Sooooo...... What this means is it might be possible to plug this dongle into, in my case, my Nexus 7 2013 Flo and Deb tablets and run GPS Rocket Locator on Android with an external battery connected to account for the high "juice" requirements.
I also have a dual boot tablet, Win/Android that has a stock USB 2.0 socket that could directly accept the 3DR receiver and two other inputs for external power. Same holds true if one owns a Winbook as it has standard and MicroUSB (for external power).
On the Windows side, one could do direct GPS mapping with any Ham APRS tracker but only the NMEA/GPS input could be used. Could see where the rocket went but wouldn't be able to navigate. Can lift the positions off into another mapping GPS and go to the last known position. The problem with most APRS Ham tracking programs is they assumed one is going to be receiving APRS packets for tracking and a local NMEA/GPS datastream is the only thing required
to keep track of "one's" position. None of the programs (except YAAC) allows anyone to define a second NMEA/GPS stream to plot. YAAC can be configured to take NMEA strings off another USB receiver and plot them while
keeping track of it's own position.
The GPS program YAAC:
https://www.ka2ddo.org/ka2ddo/YAAC.html once one puts Java in their Windows tablet will run. B/T in Windows stinks and doesn't work with YAAC at all but the 3DR USB receiver could work.
I've been able to get a B/T GPS to pair and run with Windows/YAAC so the local position should be ok.
Now YAAC is the only Windows Ham program that can keep track of two NMEA data streams at once and be setup directly. It's pretty easy as the rocket is plotted as a "pseudo" APRS position (one doesn't have to understand that) but it works.
Two other programs APRSISCE32 and the Linux Xastir can do the trick but takes some work to setup. YAAC I can reduce the instructions to a single page.
A non-Ham would legally be able to use YAAC with a 915Mhz tracker as long as they don't connect up Ham equipment or try to transmit via the internet to the APRSIS backbone.
I've messed with this before and got it to work with "wired" devices but gave up on the Windows side as I wished to use B/T peripherals. Since the 3DR is a USB receiver, might be worth looking into again and if it's eas"ier" to setup I will
try to post instructions a "real" person could effectively follow so to be able to track real time with a "map in hand". You experience that once and you'll be hooked.
If there are timing issues between the devices this could fail but what the hey, the software/maps are free and the hardware cost is nominal ( I got all the other stuff on hand) Kurt KC9LDH
