I made the mistake on the Air Avionics Transponder.

The VT-01 is NOT capable of either a SIL=1 or SIL=3 output. Therefore while it can send an ADS-B “message”, ALL USA ATC or certified ADS-B IN receivers will simply ignore the message. As such, you’re basically invisible. Not much good there....

THE solution is Trig TT22 with a TN72 GPS if you are experimental. Certified and your best choice is TT22 and TN70 GPS.

I recently completed my TT22/TN72 installation with SIL=3 and have checked my FAA report showing no errors.

Richard at craggyaero.com had the stuff in stock and provided additional help with the setup process.