I’ve been using the FlightAware 1090 antenna for about 2 years now. I recently did a clean install on my Pi and ever since have seen a difference in my reception pattern. My overall counts are about the same.
I am less than two miles from the airport and directly under the approach/departure path. I understand enough to know there will be a bit of a dead area directly above my antenna, but it used to be much smaller. I used to loose the occasional aircraft, and only for a few seconds. After the clean install of software, I’m loosing more aircraft and for longer. They are not getting picked up until they are miles away from my tower.
I’m wondering is there was a setting (gain?) that could have changed that would affect my reception pattern. At the end of the day, I am much more interested in the aircraft 375’ over my house than the ones at 37,500’ 150nm away.