Announcement

Collapse
No announcement yet.

Do I need a Filter? - Find RF Signals In Area

Collapse
This is a sticky topic.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Originally posted by abcd567 View Post


    Install graphs (by wiedehopf) to compare performance with & without filter by giving this command :
    Thanks for the idea, but I have a dangerously slow and old microSD on the original 256MB Raspberry Pi, I think I will perform a spectrum scan again and then look at my FR24 sender stats to get a better picture of the situation.
    I will report back once the jetvision 5dbi antenna and the filter are in place instead of the indoor antenna

    Comment


    • #32
      Thank you for this useful guide.

      I'm in an area with a cell mast about 500m away. I've produced two scans, unfiltered and then with the FA blue filter. Even after the filter there is some interference though reduced. I'm using the Jetvision dongle.

      Is there anything else to try eliminate the interference completey?

      scan-1c.png
      scan-2c.png

      EDIT to add:

      I think maybe changing the jetvision dongle to a FA pro-plus stick with the dark blue 1090 bandpass filter would be the required upgrade in my location to best eliminate the interference. I don't mind the extra outlay, though I can't find any stock in the UK or anywhere that ships here.

      Does anyone with experience think that getting the interference reduced more will help much or just make a small difference? Or without trying is it difficult to say?
      Attached Files
      Last edited by btb43; 2020-05-19, 10:46.

      Comment


      • #33
        Originally posted by btb43 View Post
        I think maybe changing the jetvision dongle to a FA pro-plus stick with the dark blue 1090 bandpass filter would be the required upgrade in my location to best eliminate the interference. I don't mind the extra outlay, though I can't find any stock in the UK or anywhere that ships here.
        Currently NOT available at PiHut, UK
        FlightAware's ProStick Plus
        Flightaware's Dark Blue 1090 MHz Bandpass Filter


        Originally posted by btb43 View Post
        Does anyone with experience think that getting the interference reduced more will help much or just make a small difference? Or without trying is it difficult to say?
        Every location has different RF environment.
        At some locations a filter is very beneficial, while at some others no advantage. Without trying is it difficult to say.
        Last edited by abcd567; 2020-05-19, 12:06.

        Comment


        • #34
          Originally posted by abcd567 View Post
          Every location has different RF environment.
          At some locations a filter is very beneficial, while at some others no advantage. Without trying is it difficult to say.
          The filter I was using to produce the before and after scans above is actually the 'Radarbox' one, for some reason i thought it was made by Flightaware, just me getting mixed up. It already makes a difference but as can be seen from the scans doesn't completely get of the cell mast interference.

          I've now ordered the FA Pro-Plus version dongle, which came in stock on Amazon UK, so with the built in pre-amp and filter I'll re-scan for interference when it arrives and be able to compare results then. Will be interesting to see how it compares with the jetvsion dongle and radarbox filter.

          Comment


          • #35
            Hi There,

            I just got mine set up in the last month with the A3 1090 JetVision antenna and the ADS-B dongle. I live on a hill (19 meters / 63 feet above sea level) and the antenna is mounted on my roof (i am the highest house) apart from a few trees there is no objects. I do have cell towers about 500 meters away which seem to give me a lot of interference. I gather a filter is needed but i wanted to ask which would be good for this kind of noise? Currently my max range is about 50-60nm.

            Thanks you.
            scan.png
            Attached Files

            Comment


            • #36
              Hi igi,

              I'm not an expert and can't quite see the detail on your scan image but it looks very similar to mine earlier in this thread. I'd suggest a FlightAware filter but make sure you get the right one! There is a 'new' version that allows 1080MHz - 1100MHz. This is the version you want with the narrower pass band frequency range.

              https://thepihut.com/products/flight...ass-sma-filter

              Adding one of these improved my reception as, I think, the signals you have at lower frequencies can mask the less powerful 1090 signals that you're after. I think I saw an increase in range but more noticeable was the number of hits that I got within my current range.

              Matt

              Comment


              • #37
                Fully agree with mattdav.
                Purchase Flightaware Dark Blue Filter.
                Do NOT purchase the Light Blue one, it wont help in your situation.


                FA-Filter-Dark-Blue.png . . FA-Filter-Light-Blue.jpg


                20x20.png
                Last edited by abcd567; 2020-08-30, 22:23.

                Comment


                • #38
                  Hi,

                  I'm using a Raspberry Pi equipped with RTL-SDR RTL2832U DVB-T Tuner Dongle, RTL-SDR BLOG 1090 MHZ ADS-B LNA and a selfmade spider-antenna.

                  The RTL-SDR BLOG 1090 MHZ ADS-B LNA has a triple filter built in, but there seem to be lots of signals in the range between 930 and 960 Mhz caused by a GSM-antenna 60 meters away from my ADS-B-antenna...

                  Could you give me an advice for a suitable filter for my setup?

                  Thanks!


                  scan.png

                  scan.jpg

                  Comment


                  • #39
                    ABi69

                    You have interference from GSM950. Purchase Flightaware Dark Blue Filter.

                    Do NOT purchase the Light Blue one, it wont help in
                    your situation.


                    FA-Filter-Dark-Blue.png . . FA-Filter-Light-Blue.jpg

                    Comment


                    • #40
                      Thank you very much!

                      Comment


                      • #41
                        Originally posted by ABi69 View Post
                        I'm using a Raspberry Pi equipped with RTL-SDR RTL2832U DVB-T Tuner Dongle, RTL-SDR BLOG 1090 MHZ ADS-B LNA

                        The RTL-SDR BLOG 1090 MHZ ADS-B LNA has a triple filter built in,
                        RTL-SDR BLOG LNA comes in two versions, one without filter, other with triple filter. Both look very similar.

                        Are you sure you have the triple-filter one? If you had tripls filter one, it is unlikely you will still get 960 Mhz interference.


                        TRIPLE-FILTERED 1090 MHZ LNA

                        RTL-SDR-Triple-Filtered-1090LNA.jpg




                        WIDE-BAND LNA

                        RTL-SDR-WideBand-LNA.jpg

                        Comment


                        • #42
                          Very sure...
                          I hope that this is not a fake device, but i bought it directly from their ebay-shop.

                          https://www.ebay.de/itm/RTL-SDR-Blog...d/283992357982

                          IMG_20201020_010647.jpg

                          Comment


                          • #43
                            In this case adding another filter (FA dark blue) may or may not help. Only by installing it you will know. As Spider is a low gain antenna (2 dBi), the insertion loss of the additional filter may reduce performance. However these are possibilities, and you can know if it improves, remains same, or decreases performance only after installing FA dark blue filter.

                            Comment


                            • #44
                              Just because you see something in the scan doesn't necessarily mean you need extra filtering.

                              If you have good range, no need to try extra filtering.
                              But with a mobile transmitter that close it could be benficial but it's basically impossible to tell without trying.

                              Comment

                              Working...
                              X