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Encoder Question

Pilotjim77

Well Known Member
I've been reading here on the forum about ADS-B, transponders, etc, and I have a question. I am removing steam gauges and installing a first generation GRT Horizon dual efis setup. I have a Garmin GTX 320A transponder. Does the GRT efis function as an encoder? And if so, is there any benefit or reason to keep the standalone altitude encoder?

I will also be installing the uAvionix Echo ADS-B package from GRT once they come in (currently back ordered.)

Thanks

Jim
 
Nope

Your encoder stays as is Jim. I have safe fly 2020 and Echo UAT installed, linked to my vintage GRT Sport SX. Win is the Safe Fly WAAS now drives the Sports GPS vs the Sport?s internal GPS that is non WAAS.
 
I would keep the encoder. Here?s my logic: The original WS and HS GRT efis boxes can provide a gray code and/or an RS232 input to a transponder. I think the 320 needs the gray code. But gray codes are going away. Newer transponders may only take RS232, and newer EFIS units don?t provide gray code. Should you upgrade the efis but not the transponder, you?ll want that old encoder. If you upgrade the transponder but not the efis, you?ll need the rs232. So keep the encoder AND install a wire (for now, just put a shrink wrap over the end) to an RS232 output on the efis, for later use.
BTW, your choice of adsb out sniffs the transponder, so okay. But if you choose another route, remember that the adsb and the transponder must get their altitude from the same source - not one from a remote encoder, and one from the efis.
 
I would keep the encoder. Here?s my logic: The original WS and HS GRT efis boxes can provide a gray code and/or an RS232 input to a transponder. I think the 320 needs the gray code. But gray codes are going away. Newer transponders may only take RS232, and newer EFIS units don?t provide gray code. Should you upgrade the efis but not the transponder, you?ll want that old encoder. If you upgrade the transponder but not the efis, you?ll need the rs232. So keep the encoder AND install a wire (for now, just put a shrink wrap over the end) to an RS232 output on the efis, for later use.
BTW, your choice of adsb out sniffs the transponder, so okay. But if you choose another route, remember that the adsb and the transponder must get their altitude from the same source - not one from a remote encoder, and one from the efis.

Very good explanation, Thanks, Bob.
 
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