I intermittently see aircraft that only send TIS-B data. That data doesn't appear consistently, let alone all the other problems with TIS. But it's better than not seeing an aircraft at all. How does the TIS-B data get received? Is it only on 978, does it come across all 1090 feeders? I'm not asking "what is TIS-B", I'm asking "how does it make it into adsbexchange".
Aircraft don't send TIS-B, ATC towers do. 1090 as well as 978. But they only send it when certain conditions are met. As in they will only send a target when an aircraft that has ADS-B in is in the area and can't already receive the other aircraft via ADS-B in. So basically ADS-B in gets data from TIS-B for the aircraft on the "other" frequency. Yeah it think that's about it.
