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Confused about Dynon Mode S transponder and gps data

Mdragon

Active Member
I am looking at getting rid of my old Narco tx and adding the Dynon mode s box to the system. After talking with an avionics guy today, he wasn't sure if the HDX 800's I have would feed the altitude to the Mode S box. I have the older gps puck instead of the WAAS.

Anyone know if this would work?

If not may go another route on a new transponder.

thanks
 
I’m confused by your questions. The Dynon transponder is basically a re-packaged Trig TT22. It can be fed altitude data from the Dynon EFIS via an RS232 line. That will get you a mode S transponder. However I think you are asking about ADSB-out? e.g., mode S-ES? For that, you are correct, you need an ‘approved’ (either by the manufacturer or TSO’d) GPS, and so far only WAAS GPS boxes have met the specs. So you would need to also add an approved gps. They are available for $500.
 
Dynon transponder

To answer your question, yes, the HDX via one of the SkyView RS232 serial ports is connected to the transponder, and if SkyView RS232 Serial Port is programmed correctly, will pass the encoded altitude to the transponder.

It will not be ADSB OUT certified unless you use the GPS2020 puck, via the HDX, or another certified GPS position source wired directly to the RS232 input into the transponder. Also you will need to program the transponder GPS input setup in SkyView correctly.

Brian
 
That helps guys. The gentleman who I was speaking with is quite knowledgeable about airplanes, but said he wasn't sure the dynon would feed the transponder for altitude, or if you needed an approved source like a garmin 430, etc. He doesn't do a lot of experimentals.
 
That helps guys. The gentleman who I was speaking with is quite knowledgeable about airplanes, but said he wasn't sure the dynon would feed the transponder for altitude, or if you needed an approved source like a garmin 430, etc. He doesn't do a lot of experimentals.

Just to clarify: the 430 gps does not measure pressure altitude, which is what you have to feed the transponder. The Dynon efis does have a pressure altitude encoder, not TSO’d, but the faa seems okay with it as long as it passes the biennial transponder check. (Note: I think Canada has different rules). You do need an ‘approved’(in the US and EAB, either by the manufacturer or faa TSO) gps if you want to add mode S-ES (e.g., ADSB-out) capability. There are some $500 choices, and some very expensive choices, for that gps.
 
Just to clarify: the 430 gps does not measure pressure altitude, which is what you have to feed the transponder. The Dynon efis does have a pressure altitude encoder, not TSO’d, but the faa seems okay with it as long as it passes the biennial transponder check. (Note: I think Canada has different rules). You do need an ‘approved’(in the US and EAB, either by the manufacturer or faa TSO) gps if you want to add mode S-ES (e.g., ADSB-out) capability. There are some $500 choices, and some very expensive choices, for that gps.

What are the 500$ options? I am only familiar with GPS 20a from Garmin

Thanks!
Oren
 
Get the Dynon GPS-2020 receiver puck - it's physically the same size and same wiring as your current Dynon GPS-250 receiver puck, put it in the same place, and you will be fine for ADSB-out.

https://dynonavionics.com/gps-receiver-module.php

And as mentioned above, yes the Dynon EFIS will pass pressure altitude to the transponder.
 
Get the Dynon GPS-2020 receiver puck - it's physically the same size and same wiring as your current Dynon GPS-250 receiver puck, put it in the same place, and you will be fine for ADSB-out.

https://dynonavionics.com/gps-receiver-module.php

And as mentioned above, yes the Dynon EFIS will pass pressure altitude to the transponder.

I am wired to GPS 20a of garmin (Connector already in place), but was avoiding to purchase since ADS out not required in Israel. but for 500$ will reconsider. even if required to make a new connector

Thank you all!
 
I am wired to GPS 20a of garmin (Connector already in place), but was avoiding to purchase since ADS out not required in Israel. but for 500$ will reconsider. even if required to make a new connector

Thank you all!

Is it possible to connect to a Garmin based system?
 
Is it possible to connect to a Garmin based system?
You mean other than the Garmin 20a?
The Trig TT22 (so I presume the Dynon too) can read Garmin’s proprietary RS232 format (ADSB+) available from any of their IFR GPS navigators (430W, 650, etc).
So yes, with a TSO’d gps navigator. Of course that’s not inexpensive.
 
You mean other than the Garmin 20a?
The Trig TT22 (so I presume the Dynon too) can read Garmin’s proprietary RS232 format (ADSB+) available from any of their IFR GPS navigators (430W, 650, etc).
So yes, with a TSO’d gps navigator. Of course that’s not inexpensive.

Thanks Bob
was actualy looking for other way around
I have a Garmin system with GTX 45R transponder , but have no GPS source to make the ADSB out valid
 
Okay. I do not know, but suspect the answer is ‘no’. Garmin tends to use proprietary software between its main boxes and accessories, so you have few options other than a Garmin accessory. But your 45r manual should state what formats it can read, for adsb-out data; you’d need to cross check that against what formats the non-garmin boxes put out.
 
Last edited:
GTX45R

The G3X system (GDU 4XX) can communicate with the GTX45R.
The GTX45R will get altitude and GPS position from the GDU.
TSO performance for ADS-B will not be met, but your aircraft will be
seen on flight radar.

Good luck
 

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