On Thursday, September 21, 2017 at 6:20:54 PM UTC-7, wrote:
What hasn't been discussed is how often non-approved ADSB out sources are actually being ignored.

Ah I think we've been over what matters here many times, but it is a mess.

100% of certified ADS-B in systems will ignore the ADS-B data from 100% of ADS-B Out systems that use a COTS/non-complaint GPS source 100% of the time..

So airliners, fast jets, regional jets, etc. which if they have ADS-B In at all will be a certified In system, definitely won't see some scabby ADS-B Out install using a COTS GPS source. Since many of those aircraft today have TCAS II they will be see the transponder via TCAS and be able to issue TCAS TA and RA fro that target. However the gap in the middle is with many high-end GA aircraft that have certified ADS-B In but no TCAS, they won't see a crappy COTS driven ADS-B Out. But at the low-end GA market non-certified portable ADS-B In systems will see those COTS powered targets. That is kinda brain dead but it's how it is and easy to work around.. don't use a COTS GPS source....

With the relatively low price of theTN72, if owners want to equip an experimental glider with ADS-B Out there is no excuse anymore for using a COTS GPS source. I really don't want to get into how many GA aircraft might or might not be affected, just do it properly and install a TN72 or TN70 system. COTS GPS is just the wrong thing.