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  • Do any of you know the MDS (Minimum Discernable Signal) for the conventional
    ADS-B receiver?
    In this case, the MDS would be the smallest signal measured in
    microvolts or dBm that would allow the receiver to produce error free data.
    Might assist in any Antenna/Pre-Amp additions..etc. Anyone with suitable Test Equipment or the Resources to find this out ?
    Flightradar24.com Support does not know..so if anyone can help out..(or I will have the Rx tested myself..and forward on to 'Flightradar24.com Support' !
    I am presently conducting a test after switching out the 'provided feedline' with LMR-600.. and although it has only been a few days..I have not noticed any difference in reception !
    Next Test will be done using 'Larger Antenna'..and after that, a Pre-Amp..and then ?? !

    VE6CPP
    F-CYQL1

    Comment


    • Originally posted by VE6CPP View Post
      Do any of you know the MDS (Minimum Discernable Signal) for the conventional
      ADS-B receiver?
      In this case, the MDS would be the smallest signal measured in
      microvolts or dBm that would allow the receiver to produce error free data.
      Might assist in any Antenna/Pre-Amp additions..etc. Anyone with suitable Test Equipment or the Resources to find this out ?

      VE6CPP
      F-CYQL1
      Hi Jerry. One thing I am sure of is that the DVB-T USB Receiver requires much higher MDS than FR24 supplied receiver. This conclusion is from the tests I conducted on my half-wave dipole as well as on 3-and-half element CoaxialCollinear, with only 11 feet (3.5 meters) RG6 cable between antenna & receiver. I conducted two tests on each antenna, one without amplifier, other with 13-18dB amplifier, all other factors remaining same, and range increased by 150 kms for both antennas. It seems that DVB-T's built-in pre-amplifier has much less gain than the built-in pre-amplifier of FR24 supplied receiver. 73.
      Last edited by abcd567; 2014-01-17, 20:48.

      Comment


      • I'm just wondering if its worth splitting this thread into threads for dipoles, whips, Coco's, franklins, etc.

        Sent from my Nexus 4 using Tapatalk

        Comment


        • Originally posted by VE6CPP View Post
          Do any of you know the MDS (Minimum Discernable Signal) for the conventional
          ADS-B receiver?..........

          VE6CPP
          F-CYQL1
          The DVB-T USB Receiver Dongle has front-end chip R820T. May be this datasheet can provide some info you want:
          http://www.ab9il.net/software-define..._datasheet.pdf
          Right Click the above link and then select "save as" or "save link as" to download pdf document
          Last edited by abcd567; 2014-01-18, 22:10.

          Comment


          • I'm curious would there be any lose of range when using the 10 metre cable provided with FR24 equipment to connect antenna to receiver compared with the 5 metre cable?

            Mike

            Comment


            • Originally posted by mickopla View Post
              I'm curious would there be any lose of range when using the 10 metre cable provided with FR24 equipment to connect antenna to receiver compared with the 5 metre cable?

              Mike
              It depends on which cable is supplied by FR24. One of the following 2 is most likely:

              For RG58 Cable
              At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 17.5dB x 30.5/100 = 5.1 dB
              Using 5m will reduce loss by 2.55dB

              For LMR400 Cable
              At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 4.3dB x 30.5/100 = 1.3 dB
              Using 5m will reduce loss by 0.65dB

              Comment


              • Originally posted by abcd567 View Post
                It depends on which cable is supplied by FR24. One of the following 2 is most likely:

                For RG58 Cable
                At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 17.5dB x 30.5/100 = 5.1 dB
                Using 5m will reduce loss by 2.55dB

                For LMR400 Cable
                At 1000 Mhz, Loss in 10 m (30.5 ft) cable = 4.3dB x 30.5/100 = 1.3 dB
                Using 5m will reduce loss by 0.65dB
                Thanks adcd567 for the info. Receiver is in the loft so will check tomorrow and see which one i have.

                Mike

                Comment


                • The cable provided with the FR24 is h155 belden.

                  http://www.kassex.cz/files/default/c...0%28PVC%29.pdf

                  h155 10 m Loss at 1000Mhz is 2.96 dB

                  LMR-400 10 m Loss at 1000MHz is 1.30 dB


                  This is why I went with LMR-400
                  Last edited by 1090 MHz; 2014-01-25, 02:28.
                  www.ADS-B.ca

                  Comment


                  • Originally posted by 1090 MHz View Post
                    The cable provided with the FR24 is h155 belden.

                    http://www.kassex.cz/files/default/c...0%28PVC%29.pdf

                    h155 10 m Loss at 1000Mhz is 2.96 dB

                    LMR-400 10 m Loss at 1000MHz is 1.30 dB


                    This is why I went with LMR-400
                    Your mast is 60 feet (almost 20 meters) high, plus horizontal run of cable say 5 meters, your total cable length from antenna to receiver is about 25 meters.
                    By using LMR400 instead of H155, you reduced signal loss by 4.2dB**. You took a very wise decision to use LMR400.

                    **29.6dBx25m/100m - 13dBx25m/100m = 7.4dB - 3.2dB = 4.2dB

                    Comment


                    • Originally posted by abcd567 View Post
                      Your mast is 60 feet (almost 20 meters) high, plus horizontal run of cable say 5 meters, your total cable length from antenna to receiver is about 25 meters.
                      By using LMR400 instead of H155, you reduced signal loss by 4.2dB**. You took a very wise decision to use LMR400.

                      **29.6dBx25m/100m - 13dBx25m/100m = 7.4dB - 3.2dB = 4.2dB
                      As an experiment I installed a 3dB attenuator at the radio to simulate what it would have been like if I had used the provided H155 cable. At first I didn't notice any difference, but after a while I started to notice I was not seeing as many aircraft on the ground at CYYZ, also my radar lock would drop much more frequently having another station take me over. So having that extra gain really does help you at the end of the day.
                      www.ADS-B.ca

                      Comment


                      • Originally posted by 1090 MHz View Post
                        The cable provided with the FR24 is h155 belden.

                        http://www.kassex.cz/files/default/c...0%28PVC%29.pdf

                        h155 10 m Loss at 1000Mhz is 2.96 dB

                        LMR-400 10 m Loss at 1000MHz is 1.30 dB


                        This is why I went with LMR-400
                        In real world terms distance wise what gain in km's would the LMR 400 have over the h155?

                        Also to shorten the h155 10m cable provided by FR24 would a crimping tool be required?

                        Comment


                        • Originally posted by mickopla View Post

                          Also to shorten the h155 10m cable provided by FR24 would a crimping tool be required?

                          Don't modify that cable. You agreed that it is still property of FR24.
                          I asked same question couple a months ago.
                          For official support use Contact Form

                          Comment


                          • Originally posted by Amper View Post
                            Don't modify that cable. You agreed that it is still property of FR24.
                            I asked same question couple a months ago.
                            That's why I went with a custom made LMR-400 cable. The FR24 h155 remains unused and untouched.
                            www.ADS-B.ca

                            Comment


                            • Originally posted by 1090 MHz View Post
                              That's why I went with a custom made LMR-400 cable. The FR24 h155 remains unused and untouched.
                              Just out of curiosity, what is the cost of LMR400 for say 25 meters length?

                              Comment


                              • Originally posted by abcd567 View Post
                                Just out of curiosity, what is the cost of LMR400 for say 25 meters length?
                                $60 USD for 100ft

                                http://www.ebay.com/itm/100-feet-LMR...item5884d968a6

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