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  #1  
Old 11-07-2019, 03:36 PM
Pilotjim77 Pilotjim77 is offline
 
Join Date: Jun 2018
Location: CHESHIRE, MA
Posts: 127
Default Encoder Question

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
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  #2  
Old 11-07-2019, 07:17 PM
BH1166 BH1166 is offline
 
Join Date: Nov 2017
Location: Eatonton Georgia
Posts: 97
Default 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 Sportís internal GPS that is non WAAS.
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  #3  
Old 11-07-2019, 08:51 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,980
Default

I would keep the encoder. Hereís 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 donít provide gray code. Should you upgrade the efis but not the transponder, youíll want that old encoder. If you upgrade the transponder but not the efis, youíll 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.
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  #4  
Old 11-08-2019, 08:55 AM
Pilotjim77 Pilotjim77 is offline
 
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Location: CHESHIRE, MA
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Default

Quote:
Originally Posted by BobTurner View Post
I would keep the encoder. Hereís 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 donít provide gray code. Should you upgrade the efis but not the transponder, youíll want that old encoder. If you upgrade the transponder but not the efis, youíll 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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  #5  
Old 11-08-2019, 10:08 AM
Mike S's Avatar
Mike S Mike S is online now
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Default

Yep, what Bob said.
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