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  • Originally posted by Rooster View Post
    .........What are you guys using for live plots?
    I did my tests with a signal generator + antenna analyser...

    Sent using Tapatalk from my ZX81
    Wow! You got nice test equipment. I have only one piece of test equipment: a multitester (ac/dc volt, amp, ohm, continuity), sensetivity 20k ohm/v dc, 10k ohm/v ac, analog (moving needle) $9 only.


    Sent from my N762 using Tapatalk 2
    Last edited by abcd567; 2013-11-26, 22:05.

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    • Originally posted by Rooster View Post
      Built my 10 element today, and tried the 3 top configurations... The 1/4 top whip wins hands down, with almost 2db gain over the shorted top...
      Not bothering with an amp at this stage.
      What are you guys using for live plots?
      I did my tests with a signal generator + antenna analyser...

      Sent using Tapatalk from my ZX81
      Am using same home made antenna as you except 8 element. 10 and 12 element gave me weaker results. Tested with and without amp at masthead and with amp was winner by miles (km) Pun intended... I also am using a very cheap FM Trap filter just after the power injector. I have no idea why 8 element only works better for me. Test equipment? What test equipment... Wsh I had an antenna analyzer. One thing I do use is SDRSharpe.exe to see how far off my actual 1090 MHz reception is which is 1089.965 mhz. The reason it is off is because of the fiberglass tube. No way around that. Need something rigged to hold antenna straight up. PVC tubing was much farther off.
      Last edited by andyk1; 2013-11-26, 22:20.
      Andy T-KTIK1

      RPI - http://Temporarily off Line due to t...98.37.214:8080

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      • Originally posted by andyk1 View Post
        ... I do use is SDRSharpe.exe to see how far off my actual 1090 MHz is which is 1089.965
        I'd bet that's an error with sdr#!

        Sent from my ZX81

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        • Originally posted by andyk1 View Post
          ....... Test equipment? What test equipment... .....
          Well said. You seem to have good sense of humor...


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          • Test plots - I used ADSBscope on windows, after persuading dump1090 on the Pi to work in a mode compatible with it..


            Sent from my GT-P5110 using Tapatalk

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            • Originally posted by peterhr View Post
              Test plots - I used ADSBscope on windows, after persuading dump1090 on the Pi to work in a mode compatible with it..


              Sent from my GT-P5110 using Tapatalk
              I also use adsbScope on my Windows PC / Laptop to plot the aeroplanes as well as ranges for various elevations of aeroplanes. Reason is simple: the "adsbScope" is free of charge, while "Plane Plotter" is not .

              Sent from my N762 using Tapatalk 2
              Last edited by abcd567; 2013-11-26, 23:19.

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              • When used with inLine Amplifier, my fullwave Franklin Collinear works better than 1/2 wave dipole and 3-and-half element Coco.

                When working without Amplifier, 1/2 wave dipole is #1, Coco is #2, and Franklin is #3. This seems to be due to very high impedance of fullwave Franklin.

                I wound an impedance matching, air-core, auto-transformer 1:6 turns ratio (= 1:36 impedance ratio) and connected. Phooosh!!! The inductor in my power injector fried! I forgot that transformer winding will short-circuit core & braid and did not insert a capacitor.

                I removed amplifier & power injector and ran two tests (1) with transformer & (2) without transformer. The range with transformer is far less than range without transformer. This is contrary to my expectations! Cannot make out the reason. Can anyone explain why?

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                Last edited by abcd567; 2013-11-28, 01:05.

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                • Originally posted by Rooster View Post
                  I'd bet that's an error with sdr#!

                  Sent from my ZX81
                  Not sure it was. I tried the antenna inside Electrical grade PVC, Water grade PVC and fiber glass. All gave be different tuning results. The best was no protective tubing and antenna hanging from a tree using fishing line. Of course that's not practical considering the weather in mid-western and southern US. Even with just the antenna hanging from a tree it wasn't dead on... 1089.993 mhz. Using Electrical grade PVC it was 1089.925 and water grade PVC was 1089.956. Fiberglass tube showed. 1089.965. mhz. These where all tested a few times back and forth to verify the results. For me anyway... Elec grade PVC is the worse to use for weather proofing. Fiber glass tubing had the better result.
                  Last edited by andyk1; 2013-11-28, 01:43.
                  Andy T-KTIK1

                  RPI - http://Temporarily off Line due to t...98.37.214:8080

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                  • Originally posted by andyk1 View Post
                    ...... The best was no protective tubing and antenna hanging from a tree using fishing line....
                    This reminds me of the old days when death punishment was given by hanging. The standard way a judge will write the verdict was: "To be hanged till death"


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                    • Originally posted by andyk1 View Post
                      Not sure it was. I tried the antenna inside Electrical grade PVC, Water grade PVC and fiber glass. All gave be different tuning results. The best was no protective tubing and antenna hanging from a tree using fishing line. Of course that's not practical considering the weather in mid-western and southern US. Even with just the antenna hanging from a tree it wasn't dead on... 1089.993 mhz. Using Electrical grade PVC it was 1089.925 and water grade PVC was 1089.956. Fiberglass tube showed. 1089.965. mhz. These where all tested a few times back and forth to verify the results. For me anyway... Elec grade PVC is the worse to use for weather proofing. Fiber glass tubing had the better result.
                      The tuning of the antenna has NOTHING to do with the frequency displayed in the software... You could stick a 6 inch nail into the reciever as an antenna and you would still receive 1090mhz!

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                      • Originally posted by Rooster View Post
                        The tuning of the antenna has NOTHING to do with the frequency displayed in the software... You could stick a 6 inch nail into the reciever as an antenna and you would still receive 1090mhz!

                        Sent using Tapatalk from my ZX81
                        Any coducting object is an antenna. When listening to radio, if I notice that an fm , vhf, uhf, or shortwave signal is weak, I simply touch the whip antenna or antenna terminal of my reciever, and this greatly improves reception. Of course I will never do this to the antenna of a transceiver or transmitter.

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                        Last edited by abcd567; 2013-11-28, 05:52.

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                        • Originally posted by Rooster View Post
                          The tuning of the antenna has NOTHING to do with the frequency displayed in the software... You could stick a 6 inch nail into the reciever as an antenna and you would still receive 1090mhz!

                          Sent using Tapatalk from my ZX81
                          There is a very good youtube video I watched that had to deal with ham radio antenna's and tuning. Since I didn't save it I can't send you a link but am sure with a little searching you can find it. It's a three part video.

                          In it, it shows all the materials we have all been using and testing. PVC, water and electrical grade and fiberglass. In it he uses a professional freq spectrum analyzer, a freq generator or whatever it was called. He demonstrates how the material used for weather proofing affects the incoming freq around 140 mhz. I don't remember the exact freq. He very carefully demo's everything including the distances from other objects that would affect the incoming signal. i.e two times the distance compared to the length of an antenna.

                          Considering how cheaply made these sdr dongles are made and my own tests to verify that... I'm inclined to agree with what I saw on my own tests also. For me... different weather proofing material did matter for my range and distance. To compensate for the freq shift I simple changed it to the center of whatever SDRsharp.exe waterfall in Windows showed me as the optimum incoming 1090 freq then used that freq in my RPi's dump1090 software as --freq 1089.9whatever and it seemed to help a lot. Also --gain 32.9 had to be used or no incoming signal . This is after a lot of testing that was both frustrating and bothersome and hours and hours of wasted time. I also tested local FM signals with stock antenna that came with dongle and it was dead on for 104.1 reception using SDRSharp. It was also close but not dead on for 1090 MHz but closer than my home built antenna.

                          I also understand I can still receive 1090 MHz even though the signal is off a bit but that is because both RTL1090 and dump1090 use a wideband signal on both side of 1090 to capture the incoming freq by 20.000 or 200.00 mhz. I don't remember which.

                          Sorry to say but I never tried a 6" nail to test as I never thought about that but have used bare metal coat hangers before . Maybe next round of testing when the weather warms up... next spring...
                          Last edited by andyk1; 2013-11-29, 01:30.
                          Andy T-KTIK1

                          RPI - http://Temporarily off Line due to t...98.37.214:8080

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                          • Originally posted by abcd567 View Post
                            This reminds me of the old days when death punishment was given by hanging. The standard way a judge will write the verdict was: "To be hanged till death"


                            Sent from my N762 using Tapatalk 2
                            Funny... Hung by fishing line must be the worse...
                            Andy T-KTIK1

                            RPI - http://Temporarily off Line due to t...98.37.214:8080

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                            • Can anyone else here... just out of curiosity... use SDRShape.exe (SDR# is same program) for Windows and test your 1090 MHz income freq and see how close it is to 1090 if not dead on. And mention which SDR dongle you use.

                              I for one have been using Nooelec R820T SDR &DVB-t ver 2 ($22.99 US ) and also 3x DVT-T + DAB +FM (R820) also ($12.00 US). All 4 brought from amazom.com
                              Last edited by andyk1; 2013-11-29, 19:28.
                              Andy T-KTIK1

                              RPI - http://Temporarily off Line due to t...98.37.214:8080

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                              • Originally posted by andyk1 View Post
                                Can anyone else here... just out of curiosity... use SDRShape.exe for Windows and test your 1090 MHz income freq and see how close it is to 1090 if not dead on. And mention which SDR dongle you use.

                                I for one have been using Nooelec R820T SDR &DVB-t ver 2 ($22.99 US ) and also 3x DVT-T + DAB +FM (R820) also ($12.00 US). All 4 brought from amazom.com
                                I have 2 from Nooelec $26 cost+shipment aproximately+ 1 from China $10 cost+shipment. I did not notice any difference in performance. I have SDR#. I use it to listen FM on my computer . Please tell me how to use it to measure antnna frequency.

                                Sent from my N762 using Tapatalk 2



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                                Last edited by abcd567; 2013-11-29, 02:32.

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