In the past week or so the number of aircraft that I have been receiving has decreased about in half.
Just checked my antenna and Pi in the attic and everything appears to be unchanged.
Has something changed in the software or settings?
I am now using 3.8.0~bpo9+1 with a Pro Stick Plus and the
FlightAware 1090 MHz ADS-B Antenna. I had been at 3.7.2 but I just updated with no obvious improvement in reception.
Over what time span have you noticed the reduction? If you had normally been receiving an average of 100 flights but now 50, is it really 50 all day or is it 100 for an hour and then 0 for an hour to average out to 50? If the latter, it would seem likely that you may have an intermittent connection with the dongle in the RaspPi or the coax connectors. Does your hourly grid show all blue squares or are there any blacked out squares? Otherwise, it could be any number of hard-to-diagnose things such as increased noise from some external source, for example. If you have a spare RaspPi and can swap out, that would help to start the process of isolating the problem.