Positions Reported

FlightAware ADS-B Flight Tracking
21

Using dump 1090 I’m unable to access Skyview
1.15Dev

pi@raspberrypi:~ $ cat /run/dump1090-mutability/stats.json | grep total
“total”:{“start”:1546548505.5,“end”:1546549285.7,“local”:{“samples_processed”:18 46411264,“samples_dropped”:0,“modeac”:0,“modes”:2963160,“bad”:1127433,“unknown_i cao”:1300552,“accepted”:[522095,13080],“signal”:-16.5,“noise”:-33.4,"peak_signal ":-2.4,“strong_signals”:68},“remote”:{“modeac”:0,“modes”:3549,“bad”:0,“unknown_i cao”:0,“accepted”:[3549,0]},“cpr”:{“surface”:1,“airborne”:31131,“global_ok”:3059 6,“global_bad”:0,“global_range”:0,“global_speed”:0,“global_skipped”:47,"local_ok ":361,“local_aircraft_relative”:0,“local_receiver_relative”:0,“local_skipped”:17 5,“local_range”:174,“local_speed”:0,“filtered”:291},“altitude_suppressed”:0,"cpu ":{“demod”:113624,“reader”:63494,“background”:9978},“tracks”:{“all”:93,“single_m essage”:8},“messages”:538724

22

You could always uninstall dump1090 and install dump1090-fa.
Alternatively it’s not that complicated to display RSSI in the map that comes with dump1090-mutability.
But both is not really necessary as the json file tells you all you need to know about signal strength.

Anyways regarding the gain:

Dividing the number of messages > -3dB
“strong_signals”:68
by the sum of all valid messages
“accepted”:[522095,13080]"

Gives you a percentage.
Yours is very low (0.01%), so you normally can increase gain without losing any messages due to them being too strong…
But i just checked and dump1090 was restarted recently (that is in there as well), so either calculate it yourself some time tomorrow when there has been more traffic around or just post it agagin :slight_smile:

I run my receiver around 4.5% “strong” messages.
A conservative approach is running it at 1% or lower.

23

Hi again

Yesterday I reduced the gain down to 22.9 and things look better?

Maths is not my strong point!

~ $ cat /run/dump1090-mutability/stats.json | grep total

"total":{"start":1546548505.5,"end":1546599805.7,"local":{"samples_processed":123094302720,"samples_dropped":0,"modeac":0,"modes":211064534,"bad":87243092,"unknown_icao":100347571,"accepted":[22848292,625579],"signal":-15.2,"noise":-33.3,"peak_signal":-0.4,"strong_signals":33761},"remote":{"modeac":0,"modes":106206,"bad":0,"unknown_icao":0,"accepted":[106206,0]},"cpr":{"surface":84,"airborne":1488773,"global_ok":1467843,"global_bad":1166,"global_range":1154,"global_speed":8,"global_skipped":2032,"local_ok":14249,"local_aircraft_relative":0,"local_receiver_relative":0,"local_skipped":5599,"local_range":5531,"local_speed":19,"filtered":6949},"altitude_suppressed":0,"cpu":{"demod":6706412,"reader":4121402,"background":593605},"tracks":{"all":1491,"single_message":451},"messages":23580077}

24

Nah i would rather increase the gain.
Your current numbers are 0.14% signals that are strong.
The higher the gain the higher the percentage will be.

Try 28 for a couple of hours, post the file again and we will see from there.
You can probably also run 30 without a problem.

Anyway you can just plug two numbers in the windows or any other calculator and divide them.
You get a small number you multiply by 100 to get the percentage.

25

Hi wiedehopf
I have reduced the gain to 30.0 and will get back to you later
Thanks

26

Oops increased to 30.0

27

Hi wiedehopf

After testing for two hours I think the Jury is still out?

pi@raspberrypi:~ $ cat /run/dump1090-mutability/stats.json | grep total

"total":{"start":1546604415.5,"end":1546613595.6,"local":{"samples_processed":22009741312,"samples_dropped":0,"modeac":0,"modes":117210023,"bad":66193522,"unknown_icao":41961917,"accepted":[8777792,276792],"signal":-9.8,"noise":-23.6,"peak_signal":-0.6,"strong_signals":240650},"remote":{"modeac":0,"modes":35994,"bad":0,"unknown_icao":0,"accepted":[35994,0]},"cpr":{"surface":232,"airborne":585385,"global_ok":577286,"global_bad":57,"global_range":0,"global_speed":30,"global_skipped":910,"local_ok":6627,"local_aircraft_relative":0,"local_receiver_relative":0,"local_skipped":1647,"local_range":1511,"local_speed":24,"filtered":0},"altitude_suppressed":0,"cpu":{"demod":2216072,"reader":814133,"background":128667},"tracks":{"all":706,"single_message":234},"messages":9090578}

28

2.6% strong messages.

That’s just fine like that.

Let’s hope you get a few more positions :wink:

If you notice low flying planes close by vanishing then you can go down to 28. But you might not even have a lot light aircraft or helicopters in your vicinity. Or not care about them :slight_smile:

29

I suspect that the total number of aircraft have reduced slightly, but the distance tracked has increased.

No I don’t get many low flying planes, but I do get the odd Helicopter.

Thanks for the help!

Regards
Gerry

30

That does not make sense. Increasing range in almost all cases increases the aircraft count :wink:

Anyway weather and changes in traffic produce fluctuations in the numbers that is not easily accounted for. So often changes in numbers have nothing to do with changes in the setup.