Transponder 1.21K Resistor

[GHDZ]

I have upgraded the software on my GARMIN 430W and want to connect the serial data to the Skyview transponder. The installation manual shows a 1.21K Ohm resistor in series between an external GPS source and pin #3.

1 - How critical is this value?
2 - Is there any "special" configuration required for proper data handshaking?

 

[Dynon]

1) Anything that is 1.21K +/- 20% will work.
2) You need to be running the 430W with the latest available software that support ADS-B specific output, the latest version of the transponder software (see our manual for details), and then have the Garmin setup up to output ADS-B serial data on a serial port, and then have the transponder set to receive it, which is under SETUP MENU > TRANSPONDER SETUP > GPS DATA > DIRECT (GARMIN ADS-B)

 

[GalinHdz]

1) Anything that is 1.21K +/- 20% will work.
2) You need to be running the 430W with the latest available software that support ADS-B specific output, the latest version of the transponder software (see our manual for details), and then have the Garmin setup up to output ADS-B serial data on a serial port, and then have the transponder set to receive it, which is under SETUP MENU > TRANSPONDER SETUP > GPS DATA > DIRECT (GARMIN ADS-B)

Do you absolutely need to have the 1.2K resistor? What can happen if it isn't there?

Also, on another post I commented how using ADS-B format with a Garmin 430W/530W won't work on the Skyview system even with the latest Garmin software version. You have to use the Aviation Data format for it to work which is not 2020 compliant. Another Dynon poster is looking into this.

 

[dynonsupport]

Yes, you need the 1.21K resistor. You may damage the transponder without it. Plus, the transponder install manual is for a TSO'd device and you must follow the instructions to have a TSO legal install.

 

[GalinHdz]

Yes, you need the 1.21K resistor. You may damage the transponder without it. Plus, the transponder install manual is for a TSO'd device and you must follow the instructions to have a TSO legal install.

THANKS!