On Saturday, September 30, 2017 at 12:12:11 PM UTC-7, Andy Blackburn wrote:
/snip/
3) There seems to still a lot of transponder-only traffic as evidenced by all the TIS-B traffic. I am assuming that if this traffic had an ADS-B direct signal it would take display precedence over TIS-B.

Yep. The aircraft has UAT or 1090ES Out then you generally won't see TIS-B reports for it as all the client aircraft should have that data satisfied by ASD-B direct or ADS-R. There must be some cases where SSR targets are not deduplicated with Mode C transponders and broadcast anyhow. That should be a pretty low, but I don't know any numbers. I suspect you are really seeing all the folks who have yet to go ASD-B Out at all.