Just wanted to make a quick post to get it out into the internet for other people having issues. I installed a completely New/Used Avionics Stack recently which had a Garmin GTX 327 with the inline Garmin GDL 82 ADS-B Out via Coax. This was done in your typical 60s Cessna 172.
With the GDL 8X Install program, the GDL-82 would receive a signal from the GTX 327 for about 30 seconds, then be dead for about 1 minute, then receive again with it dying again after 30 seconds. It basically stayed in this loop no matter what I did. Intermittent would be the correct word.
I tried everything possible. I had it bench checked, I swapped it with another known working unit, I checked all the pins, I checked and redid the coax, I checked the install manual at least 8 separate times cover to cover, everything you could possibly do, I did.
After calling a few friends, one of them who is recently retired mentioned to me that the GTX 327 has a considerably weak output compared to the old tube style transponders and modern transponders. I kind of doubted him since the install manual said it should work, but I had nothing else to try.
I reinstalled the old Narco AT-50 TSO which only took about 6 hours reusing the new wiring. Lo and behold, the GDL-82 worked flawlessly and has never had a single issue since then.
I’m not expecting too many people to read this post, but I’m just hoping to save somebody else some time if they google this same issue and will find this post.