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  • #16
    Originally posted by wiedehopf View Post

    Also i would recommend installing graphs that show you the message rate and percentage of strong signals:
    https://github.com/wiedehopf/graphs1090#graphs1090


    I'm not sure if those will work on the pi24 image though, those images sometimes have weird write protection.
    But in my opinion those graphs are more useful for adjusting gain than that script.
    I strongly recommentd to install @wiedehopf's graphs. These are a great tool for system tune-up and monitoring.

    I have installed these graphs on
    - Raspbian image (dump1090-mutability ver 1.15~dev)
    - Piaware image (dump1090-fa)
    - PI24 image (dump1090-mutability ver 1.14)

    These work perfectly well on all three installs.
    However on Pi 24 image, the Signal Level graph is missing (cause: dump1090-mutability ver 1.14).


    Screenshots of @wiedehopf's graphs on PI24

    wiedehopf graphs on PI24.png . wiedehopf graphs on PI24-2.png
    Last edited by abcd567; 2019-03-09, 13:55.

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    • #17
      Originally posted by wiedehopf View Post
      Running such a script each day or twice a day is not a good idea.

      Especially because you want to optimize your gain for a situation with a lot of traffic not very little traffic.
      The result of the script becomes even more random with little traffic around.

      Just run it once when there is a lot of traffic around.
      Then set that gain and maybe fine tune it by hand if for example you lose close in planes because the signal is too strong but you want to receive those planes.

      Otherwise leave it.

      Running such a script at night just risks setting a random gain that is anything but optimal.

      Also i would recommend installing graphs that show you the message rate and percentage of strong signals:
      https://github.com/wiedehopf/graphs1090#graphs1090


      I'm not sure if those will work on the pi24 image though, those images sometimes have weird write protection.
      But in my opinion those graphs are more useful for adjusting gain than that script.
      I'm not doing this to find the optimum gain, I have already done that. First by running the optimising script and latterly by setting a new gain every 24 hours and gathering hits and positions stats. So I do know what my best gain setting is. The reason for this particular project is the see what happens overnight when the noise floor has dropped by 10 dB so I can turn up the gain by that much to see the effect.
      I do have the graphs too - that's how I have seen the overnight noise level drop.
      I could do the change manually every day from the embedded gain setting in maps but automating it would be a lot less hassle.

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      • #18
        That noise level is more of an approximation and doesn't necessarily mean you can receive weaker signals.

        I suppose that at night you could have no aircraft with very strong signals, so it might make a little sense.
        (For example if the Airport you live close to has no departures/arrivals)

        Apart from that i would turn up the gain until you actually start losing close in aircraft and then back off a little bit.

        Good luck with your script though, seems like a reasonable approach!

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        • #19
          I suppose I might just as well switch the gains manually for a few days to see if it's worth the effort.
          I've just about reached the best configuration possible for my location anyway with often 1.7 million hits a day with 2,500 - 2,700 aircraft - up 349 nm max and 210 nm average.
          This is a typical day showing why I thought such a test overnight might show a little improvement - very little most likely!

          ADS-B.jpg

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          • #20
            That gain looks quite low anyway, turn it up by 5.

            Or do you really already lose close in aircraft when you do that?

            Note that if you have the adsb-receiver version of the graphs, the "Messages >-3dB" graph is using incorrect values.

            But as i said i would just turn up the gain until losing close in aircraft when you look at the local map then turn it back down a bit.
            Last edited by wiedehopf; 2019-03-09, 16:37.

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            • #21
              Yes that gain is lower than optimum. I'm in the middle of plotting hits and positions per aircraft over 24 hour periods.
              Gain tests.JPG

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              • #22
                24 hour periods are sketchy.

                Intra-week changes are quite big.

                I get the impression you will soon have a dual receiver setup, one for close in traffic and another one set at higher gain

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                • #23
                  Originally posted by wiedehopf View Post
                  24 hour periods are sketchy.

                  Intra-week changes are quite big.

                  I get the impression you will soon have a dual receiver setup, one for close in traffic and another one set at higher gain
                  Already got 3!! T-EGSY1 T-EGSY73 T-EGSY74

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                  • #24
                    @Scroggie

                    If you are running dump1090-mutability ver 1.15~dev, then you can try manual method by:

                    - Add RSSI column to dump1090 map (Click Here - Post #10 of mutability thread)

                    - Click the title of added "RSSI" column to sort vales (high to low).

                    - If there are too many entries for > -3 dBfs, reduce gain by 3 dB and observe plane-count / max range.

                    - Repeat this several times till you find the "sweet point".

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                    • #25
                      Hi Captain

                      I'm not trying to optimise gain, I've already done that. This was just an experiment of increasing gain overnight because there is less noise then (10dB less)

                      I think crontab lines like these might do it
                      00 00 * * * sudo sed -i 's/GAIN=.*/GAIN=48/' /etc/default/dump1090-mutability
                      01 00 * * * systemctl restart dump1090-mutability
                      00 06 * * * sudo sed -i 's/GAIN=.*/GAIN=36.4/' /etc/default/dump1090-mutability
                      01 06 * * * systemctl restart dump1090-mutability

                      or should the restart be:- sudo /etc/init.d/dump1090-mutability restart ?
                      I have tried this half an hour ago (with appropriate timings) and ended up with no aircraft received at all I think I ended up with a gain of -36.4 so I feel I've missed something.
                      Last edited by Scroggie; 2019-03-09, 19:51.

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                      • #26
                        Just check the config file after running the command?

                        Also which crontab are you putting those entries in?

                        If it is the root crontab then you don't need sudo.
                        If it is the user crontab then you need sudo for systemctl as well.
                        Last edited by wiedehopf; 2019-03-09, 20:25.

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                        • #27
                          Originally posted by wiedehopf View Post
                          Just check the config file after running the command?

                          Also which crontab are you putting those entries in?

                          If it is the root crontab then you don't need sudo.
                          If it is the user crontab then you need sudo for systemctl as well.


                          I did check the config file and it looked correct but on the map it was showing "-36.4" (including the quotes) and no aircraft visible so I think somethings not quite right. Resetting the gain from the map button restored it to normal.

                          I don't understand which crontab is active. I used the sudo crontab -e which did make the change so I assume that is correct.
                          And which is the correct command to restart dump=mutabilty? I think both work.

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                          • #28
                            Originally posted by Scroggie View Post
                            ....I used the sudo crontab -e which did make the change....
                            I think this is root crontab, isn't it @wiederhpof?


                            Originally posted by Scroggie View Post
                            ...Resetting the gain from the map button restored it to normal.....
                            By "map button" do you mean the button you added by method given in Post #7 of mutability thread?


                            .

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                            • #29
                              Originally posted by abcd567 View Post
                              I think this is root crontab, isn't it @wiederhpof?



                              By "map button" do you mean the button you added by method given in Post #7 of mutability thread?


                              .
                              Yes here is what happens to that button
                              Map button error.JPG

                              This is how it normally looks Map button normal.JPG

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                              • #30
                                Gains should be entered in +, dump1090 default amounts passed are positive. -10 is the only one that should appear -. So you are probably triggering that somewhere with an invalid value?

                                Which makes too many chars to display on the line with "s

                                Sent from my EML-L09 using Tapatalk
                                Last edited by Oblivian; 2019-03-09, 22:28.
                                Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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