fadump1090.sh --PPM switch?

FlightAware ADS-B Flight Tracking
1

Did anyone ever figure out if the value is either positive or negative? The FA Stick Pro in SDR# (on my PC) shows a PPM offset of 75 for me… in fadump1090.sh i’m using a positive value and it seems to work better than the negative value.

I’m using the Pi 3 Mod B with the Piaware 2.1.5 image…

Stats look good from what I can tell but just wanted to know if anyone knows for sure what the value is suppose to be…

Thanks
-Nick

flightaware.com/adsb/stats/user/cnick6

2

It can be either positive or negative depending on your dongle. The value you give to dump1090 is just passed to librtlsdr, so whatever sign that librtlsdr wants.
I don’t know what convention SDR# uses.

3

SDR# for the PC wants a positive value which brings it back to a zero offset.