Announcement

Collapse
No announcement yet.

Bad antenna performance

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by abcd567 View Post
    The method to change gain depends on the software you have installed. Is your DVB-T plugged into a Windows PC or a RPi? What software you use?
    I use dump1090 on a Mac or RPi... so it's just a matter of providing a command line argument...

    Comment


    • #17
      dump1090 has several variants. Which one you use?
      (1) Integral dump1090 of Pi24 img
      (2) dump1090 Malcolm Robb
      (3) dump1090-mutability
      (4) dump1090-fa
      (5) some other variant.
      Last edited by abcd567; 2017-12-14, 06:22.

      Comment


      • #18
        Originally posted by abcd567 View Post
        dump1090 has several variants. Which one you use?
        (1) dump1090 Malcolm Robb
        (2) dump1090-mutability
        (3) dump1090-fa
        (4) some other varient.
        dump1090 Malcolm Robb I'm using...

        Comment


        • #19
          Originally posted by tintin View Post
          I use dump1090 on a Mac or RPi... so it's just a matter of providing a command line argument...
          dump1090 Malcolm Robb I'm using...
          AS YOU ARE USING dump1090 Malcolm Robb
          You can start it manually by following command, adding --gain argument like command below:
          sudo /usr/bin/./dump1090 --net --gain 40

          However you can make dump1090 start automatically at boot by following method:

          (1) Create a blank script file "dump1090.sh" with the command:
          Code:
          sudo nano /etc/init.d/dump1090.sh
          (2) Copy and paste the following code into the new file, and save the file (Ctrl+O), then exit nano text editor (Ctrl+X):
          Set Gain value in the line starting with PROG_ARGS= as shown in red below:

          Code:
          #!/bin/bash
          ### BEGIN INIT INFO
          #
          # Provides: dump1090
          # Required-Start: $remote_fs
          # Required-Stop: $remote_fs
          # Default-Start: 2 3 4 5
          # Default-Stop: 0 1 6
          # Short-Description: dump1090 initscript
          
          #
          ### END INIT INFO
          ## Fill in name of program here.
          PROG="dump1090"
          PROG_PATH="/home/pi/dump1090"
          [color=#FF0000]PROG_ARGS="--interactive --net [B]--gain 40[/B] --net-ro-size 500 --net-ro-rate 5"[/color]
          PIDFILE="/var/run/dump1090.pid"
          
          start() {
          if [ -e $PIDFILE ]; then
          ## Program is running, exit with error.
          echo "Error! $PROG is currently running!" 1>&2
          exit 1
          else
          ## Change from /dev/null to something like /var/log/$PROG if you want to save output.
          cd $PROG_PATH
          ./$PROG $PROG_ARGS 2>&1 >/dev/null &
          echo "$PROG started"
          touch $PIDFILE
          fi
          }
          
          stop() {
          if [ -e $PIDFILE ]; then
          ## Program is running, so stop it
          echo "$PROG is running"
          killall $PROG
          rm -f $PIDFILE
          echo "$PROG stopped"
          else
          ## Program is not running, exit with error.
          echo "Error! $PROG not started!" 1>&2
          exit 1
          fi
          }
          
          ## Check to see if we are running as root first.
          ## Found at http://www.cyberciti.biz/tips/shell-...ck-script.html
          if [ "$(id -u)" != "0" ]; then
          echo "This script must be run as root" 1>&2
          exit 1
          fi
          
          case "$1" in
          start)
          start
          exit 0
          ;;
          stop)
          stop
          exit 0
          ;;
          reload|restart|force-reload)
          stop
          start
          exit 0
          ;;
          **)
          echo "Usage: $0 {start|stop|reload}" 1>&2
          exit 1
          ;;
          esac
          exit 0
          (3) Make this file executable with the following command:

          Code:
          sudo chmod +x /etc/init.d/dump1090.sh
          (4) Create the run level shortcuts with the command:

          Code:
          sudo update-rc.d dump1090.sh defaults
          (5) Reboot the RPi.
          Code:
          sudo reboot
          Last edited by abcd567; 2017-12-14, 07:06.

          Comment


          • #20
            If you are using Pi24 image on your Pi, there is NO need to create the auto-start script shown in my above post.

            The Pi24 image has its own startup script for its integral dump1090.
            The integral dump1090 of Pi24 is actually dump1090 Malcom Robb, but customized for FR24 feed.
            It is started by the script in file /usr/lib/fr24/dump1090.sh.

            (1) Contents of directory /usr/lib/fr24
            Code:
            pi@raspberrypi:~ $ ls /usr/lib/fr24/
            activate-cron.sh  dump1090.sh          librtlsdr.so    librtlsdr.so.0.5git
            dump1090          fr24feed_updater.sh  librtlsdr.so.0  public_html


            (2) The code inside startup file /usr/lib/fr24/dump1090.sh
            Code:
            pi@raspberrypi:~ $ cat /usr/lib/fr24/dump1090.sh
            ./dump1090 --interactive --net --net-ro-size 500 --net-ro-rate 5 --net-buffer 5 --net-beast --mlat
            pause

            Comment


            • #21
              Originally posted by tintin View Post
              Thanks, I ordered the orange Flightaware dongle... I'll keep you updated...
              Today I received my Flight-aware dongle. After some experiments I ended up with an optimal gain setting of 28dB. With this setting I reach 314km (170nm) (see picture). Compared to the initial 80nm this is a huge improvement. I must say that in the meantime I could get 110-130nm miles with my old dongle by positioning the cable slightly different in my chimney.
              Screen Shot 2017-12-20 at 19.19.11.jpg

              Comment


              • #22
                Since your possible maximum range determined by heywhatsthat.com is 220 nm, you still are 220-170=50nm less.

                Do you have mobile/cell phone towers/antennas nearby? A strong mobile signal in range 800 to 950 will overload pro stick.

                You can easily determine presence of mobile / cell phone signal in range 800 to 1200 Mhz by method described here:

                Find Out Existing RF Signals (Cell/Mobile/Pager etc) In Your Area

                .

                Comment


                • #23
                  Originally posted by abcd567 View Post
                  Since your possible maximum range determined by heywhatsthat.com is 220 nm, you still are 220-170=50nm less.
                  Do you have mobile/cell phone towers/antennas nearby? A strong mobile signal in range 800 to 950 will overload pro stick.
                  There seems to be a strong signal at ~900MHz but not sure if this is strong enough to interfere. Would you recommend a filter? Or the blue dongle?

                  scan.jpg

                  I also forked dump1090 and modified it so it generates heat maps based on successfully received positions. Below a heat map of all positions during one day. It's nice to see how the range in certain directions is impact by my neighbours' roofs
                  Heatmap.jpg

                  Comment


                  • #24
                    Originally posted by tintin View Post
                    There seems to be a strong signal at ~900MHz but not sure if this is strong enough to interfere. Would you recommend a filter? Or the blue dongle?
                    1) Can you please post the scan.png image?

                    2) Yes, I would recommend a filter.

                    3) Do NOT go for blue dongle (Pro Stick Plus). Although it has a built-in saw filter, the filter chip is located between pre-amp and tuner, and do not protect pre-amp from getting overloaded by strong cell/mobile signals. With blue dongle you will still need an external filter.

                    I also forked dump1090 and modified it so it generates heat maps based on successfully received positions. Below a heat map of all positions during one day. It's nice to see how the range in certain directions is impact by my neighbours' roofs
                    Nice. How you modified dump1090 to get this heat map? Can you please post the steps (or link to guide)?

                    Comment


                    • #25
                      Originally posted by abcd567 View Post
                      1) Can you please post the scan.png image?
                      It is posted. Do you see that little black line in my previous post? Click on it! It seems to be rescaled though
                      Originally posted by abcd567 View Post
                      Nice. How you modified dump1090 to get this heat map? Can you please post the steps (or link to guide)?
                      It's still under development. I already uploaded an intermediate version to GitHub with an improved web interface (in my view ) but without heatmap. It already logs all airplanes and positions (once every 10sec) to a mysql database. It also extracts info about airplanes and routes from basestation & flightroute sqlite databases and shows some statistics. The web interface looks like:
                      Screen Shot 2017-12-20 at 19.19.11.jpg
                      You can find it on GitHub: https://github.com/lonesomebyte/dump1090

                      Comment


                      • #26
                        Originally posted by tintin View Post
                        It is posted. Do you see that little black line in my previous post? Click on it! It seems to be rescaled though
                        Yes, the image scan.png is so thin that I missed it initially. Scaling has made reading Mhz impossible, but cell/mobile signal is clearly very strong. Most likely a filter will improve reception and maximum range.


                        It's still under development. I already uploaded an intermediate version to GitHub with an improved web interface (in my view ) but without heatmap. It already logs all airplanes and positions (once every 10sec) to a mysql database. It also extracts info about airplanes and routes from basestation & flightroute sqlite databases and shows some statistics. The web interface looks like:
                        [ATTACH=CONFIG]9030[/ATTACH]
                        You can find it on GitHub: https://github.com/lonesomebyte/dump1090
                        Thanks. Good work.

                        Comment


                        • #27
                          Very handy thread.
                          Unfortunately the advantages of my being on an elevated site also results in a very RF rich environment. Four large TV and radio masts within 3 kms and sundry cell towers etc. I didn't have to run rtlpan on my Flightstick Pro + for long or even wait for the scan to build to see that I have immense signals in the 900-1000Mhz range. A narrow band filter is on its way, meanwhile I play with gain settings :-)

                          signal.JPG

                          Comment


                          • #28
                            GSM mast distortion

                            Near our house, about 300 meters away, there is a huge GSM mast. As it is well know GSM signal makes lots of distortion and makes it almoust impossible to listen aircraft transponder signal far away.

                            Have you any of you made shield or any kind of Faraday's cage to block signal coming from specified direction?

                            Comment


                            • #29
                              Originally posted by JasuK View Post
                              Near our house, about 300 meters away, there is a huge GSM mast. As it is well know GSM signal makes lots of distortion and makes it almoust impossible to listen aircraft transponder signal far away.

                              Have you any of you made shield or any kind of Faraday's cage to block signal coming from specified direction?

                              The problem is that you could shield the equipment in the house, but you still have to get the ADS-B signal into the receiver. I ran the RF scan without an antenna, just with a basic RTL stick and got the results shown below.

                              spectrum_no_antenna.bmp

                              Comment


                              • #30
                                Originally posted by Stealth View Post
                                The problem is that you could shield the equipment in the house, but you still have to get the ADS-B signal into the receiver. I ran the RF scan without an antenna, just with a basic RTL stick and got the results shown below.

                                [ATTACH]9119[/ATTACH]
                                There's a GSM antenna at 700m from my ADSB antenna. I've bought this filter on the internet. There are even better ones with less attenuation in the passband but this is really cheap. Still waiting for it to be delivered... Will let you know how things improve (or not )

                                Comment

                                Working...
                                X