Hi - new to the forum, have had a PiAware up for a couple of years.
I recently bought the FlightAware 1090 MHz ADS-B Antenna and mounted it up higher than my old antenna had been and have seen a lot more traffic. Every once in a while, my list of flights will burst to include LAX (I’m down in San Diego) with a bunch of ground readings. I’m wondering if this is “normal” and what I’m really seeing. I can’t imagine that my reception changes much, and even if it does, why do I only see ground info and no planes in flight up there?
For TIS-B traffic like this, the source of the signals is the ground station transmitter that’s responsible for forwarding TIS-B, not the aircraft themselves. That ground station will then be fed by various sources of data available to the FAA. There’s some set of rules internal to the FAA systems that decides what to forward to which ground stations based on, amongst other things, what aircraft with ADS-B in capabilities are nearby.
You probably have consistent reception to the ground station, and the variation you are seeing is variation in what the ground station decided to transmit, rather than changes in reception. It’s probably triggered by what else is flying nearby.
Something must have changed in my area as well the past few days since nothing else has changed on my end - TIS-B messages have increased substantially when viewing my UAT:
