can anyone help explain how i edit the ppm in piaware 3.1.0 please?
i can read the config.txt file in putty ssh and it says ppm is 0 but i would like to alter this and just can’t work out how to.
any advice appreciated
thanks Rob
It depends which version you have.
For the native Piaware setup try
sudo piaware-config rtlsdr-gain 33 (to set it to 33)
sudo piaware-config -restart
or for dump1090-mut
edit
/etc/default/dump1090-mutability
search for gain
1 Like
PPM not gain Jon
Sent from my B5060 using Tapatalk
Hi…disable piaware service…then copy next in SSH RPi session: sudo rtl_test -p
and wait some time for watch the PPM data, and after that you can change piaware parameter with next command, for example for PPM -2 you must write: sudo piaware-config rtlsdr-ppm -2
worked out how to alter ppm thanks sorry only just come across these replies as i’m not getting any notifications from any posts even though all enabled in post and profile. thanks again
just running the rtl test you said and how do you come to the correct ppm offset then from all this current ppm and cumulative ppm figures please
Run it for a while, the number you want is cumulative ppm, it averages out more over time, the longer it runs the move levelled out it becomes, not sure what is the best tine span to run it for though, mine levels out at -1 after a few minutes and doesn’t change much.
i see it says after a few mins press ctrl c and that will be your ppm i presume, mine said 0 after about 35 tests, but this is similar to Kalibrate and that gives you the finished figure after 100 tests so may let this run and see but i’m using a NooElec aluminium black TCXO on this feed and comes back on Kalibrate at 0.336ppm so under the 0.5ppm they say it will keep to.
If you’ve got a dongle with a TCXO there’s not much point worrying about a PPM offset since it’s going to be close to zero anyway. ADS-B really doesn’t care about this unless the dongle is way out.
I know but i was curious to see the difference between systems just how accurate they were, i wonder how close the new prostick plus will be??? the prostick i have is up and down like a prostitutes draws lol
Hi I’m currently doing the test above but its not stopping as i thought it would around 100 tests lines
do i have to stop the results
regards john
press ctrl +c see if it says 0
pi@tracker:/etc $ sudo rtl_test -p
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001
Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
Sampling at 2048000 S/s.
Reporting PPM error measurement every 10 seconds...
Press ^C after a few minutes.
Reading samples in async mode...
lost at least 228 bytes
real sample rate: 2048108 current PPM: 53 cumulative PPM: 53
real sample rate: 2048108 current PPM: 53 cumulative PPM: 53
real sample rate: 2048081 current PPM: 40 cumulative PPM: 48
real sample rate: 2048110 current PPM: 54 cumulative PPM: 50
real sample rate: 2048091 current PPM: 45 cumulative PPM: 49
real sample rate: 2048073 current PPM: 36 cumulative PPM: 47
real sample rate: 2048105 current PPM: 51 cumulative PPM: 47
real sample rate: 2048101 current PPM: 49 cumulative PPM: 48
real sample rate: 2048423 current PPM: 207 cumulative PPM: 65
real sample rate: 2047755 current PPM: -119 cumulative PPM: 47
real sample rate: 2048106 current PPM: 52 cumulative PPM: 47
real sample rate: 2048087 current PPM: 43 cumulative PPM: 47
real sample rate: 2048103 current PPM: 50 cumulative PPM: 47
real sample rate: 2048101 current PPM: 50 cumulative PPM: 47
real sample rate: 2048079 current PPM: 39 cumulative PPM: 47
real sample rate: 2048107 current PPM: 53 cumulative PPM: 47
real sample rate: 2048089 current PPM: 43 cumulative PPM: 47
real sample rate: 2048096 current PPM: 47 cumulative PPM: 47
real sample rate: 2048089 current PPM: 44 cumulative PPM: 47
real sample rate: 2048092 current PPM: 45 cumulative PPM: 47
real sample rate: 2048417 current PPM: 204 cumulative PPM: 54
real sample rate: 2047768 current PPM: -113 cumulative PPM: 47
real sample rate: 2048095 current PPM: 47 cumulative PPM: 47
^CSignal caught, exiting!
User cancel, exiting...
Samples per million lost (minimum): 0
47 is my figure on an old NooElec dongle! That seems quite high.
47ppm is normal enough for a non-TCXO, individual uncompensated crystals can vary by sometimes as much as +/-80ppm and the frequency will vary with temperature.
For context, 47ppm when tuned to 1090MHz is about a 0.051MHz tuning error; this is about 2% of the bandwidth captured.
I just tried to run this but an error was returned:
pi@piaware:~$ sudo service piaware stop
pi@piaware:~$ sudo rtl_test -p
Found 1 device(s):
0: Realtek, RTL2832U, SN: 00001000
Using device 0: Generic RTL2832U
usb_claim_interface error -6
Failed to open rtlsdr device #0.
Did I not have the correct commands or is it something to do with the usb wifi dongle I’m using?
You need to stop dump1090 not piaware.
sudo service dump1090 stop or
sudo service dump1090fa stop (Or something like this for the fa versions of dump1090)
Thanks! I was just going by
posted earlier