thanks. I would prefer a cavity filter as there is so much noise in NYC. Also plenty of radars and 978Mhz is only 2Mhz further from 1030Mhz radar than 1090Mhz.
I got the Hab/Nevis 978Mhz amp/filter working with Bias-t and an 1ppm TXCO RTL-SDR. It seems to be working well.
I have over 22,000 position hits since I rotated the logs at 3:46AM (It is now 3:35PM).
pi@odroidxu4:~ cat /var/log/dump978.log | wc -l
Not sure how many aircraft I see directly as the website seems to display ads-r traffic too.
I can tell on the dump978 webpage as US aircraft ICAO IDs start with A and the ADS-Rs seem to start with 2. I see a few 2acxxx aircraft at the moment. I have seen 3-5 real aircraft and up to 20 or 30 ADS-R aircraft.
I dialed the gain back to 37db. Trying to work out how to optimise the gain setting.
It would be nice if dump978 provided signal level information to the JSON or log file.
Looking at the github files, it seems that RS=?? is a corrected error level.
// Demodulate an ADSB (Long UAT or Basic UAT) downlink frame
// with the first sync bit in ‘phi’, storing the frame into ‘to’
// of length up to LONG_FRAME_BYTES. Set ‘*rs_errors’ to the
// number of corrected errors, or 9999 if demodulation failed.
// Return 0 if demodulation failed, or the number of bits (not
// samples) consumed if demodulation was OK.
Also trying to work out how to get a log file, feed the webpage with a JSON file and send to dump1090 on 30001.
The first two are working well. I could live without logging if I could get JSON and tcp 30001 working.
I ordered a ladder so should be able to put the FA Dual band antenna on the chimney in a few weeks.