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3 EASY ANTENNAS FOR BEGINNERS

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  • #46
    Originally posted by dudesjp View Post
    Hey F-EGLF1, well, the seller said that this one don't need power supply! Maybe this? In the box have just this informations:

    Technical specifications

    - Line amplifier
    - Gain = 20dB
    - Frequency: 950MHz - 2150MHz
    - Return loss : 18dB
    - Noise figure : 3,5dB
    - Impedance : 75 ohms

    What can be? Thank you
    Impedance mismatch? You have a 50 ohm system going through an LNA rated at 75 ohms.
    F-KDAG1

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    • #47
      Originally posted by Patrick Reeves View Post
      Impedance mismatch? You have a 50 ohm system going through an LNA rated at 75 ohms.
      Hey Patrick! Didn't thought in this! So, buy a new one maybe? Or there's a way to change the impedance? Thank you
      T-SBCT5/T-SBCT6

      Comment


      • #48
        Your amplifier DOES need power

        Originally posted by dudesjp View Post
        Hey F-EGLF1, well, the seller said that this one don't need power supply! Maybe this? In the box have just this informations:

        Technical specifications

        - Line amplifier
        - Gain = 20dB
        - Frequency: 950MHz - 2150MHz
        - Return loss : 18dB
        - Noise figure : 3,5dB
        - Impedance : 75 ohms

        What can be? Thank you
        Hi,
        your amplifier is designed to be used for Satellite-Receivers for your home-TV.
        Those receivers are feeding the powersupply (I think about 15 to 18 Volts but please check the voltage because I do not have one) through the coaxial cable to the amplifier, hence the mention "don't need power".
        That means you may need also 1) An suitable powersupply 2) A power Injector and 3) A DC Blocker

        Comment


        • #49
          The amp you have- like trying to fit a square peg in a round hole, IMO.

          E-bay has a boatload of ~1000 MHZ 50 ohm amps, I've been looking at this one for my own project:

          http://www.ebay.com/itm/new-20MHz-2-...3D321924700172

          Plus 3 VDC power supply, injector, blocker, probably $30-40 all in.
          F-KDAG1

          Comment


          • #50
            Originally posted by Velivole View Post
            Hi,
            your amplifier is designed to be used for Satellite-Receivers for your home-TV.
            Those receivers are feeding the powersupply (I think about 15 to 18 Volts but please check the voltage because I do not have one) through the coaxial cable to the amplifier, hence the mention "don't need power".
            That means you may need also 1) An suitable powersupply 2) A power Injector and 3) A DC Blocker
            Hey Velivole, thank you for the explanation! I have here a power injector that the guy from the satellite tv gave but I'm afraid about the current! Not even in the webpage says about this!

            Originally posted by Patrick Reeves View Post
            The amp you have- like trying to fit a square peg in a round hole, IMO.

            E-bay has a boatload of ~1000 MHZ 50 ohm amps, I've been looking at this one for my own project:

            http://www.ebay.com/itm/new-20MHz-2-...3D321924700172

            Plus 3 VDC power supply, injector, blocker, probably $30-40 all in.
            Really liked this one! But unfortunately the seller don't send to Brazil! And wich coaxial cable are you using? RG6 with 65% it's a good one?
            T-SBCT5/T-SBCT6

            Comment


            • #51
              I use the supplied Bieffe CO 100 AF coax for the FR24 box, and Belkin RG58 on an Airspy SDR for messing around on the lower bands. Have not been disappointed... I guess RG6 would work, IMO CO 100 or RG58 would be better.
              F-KDAG1

              Comment


              • #52
                Originally posted by Patrick Reeves View Post
                I use the supplied Bieffe CO 100 AF coax for the FR24 box, and Belkin RG58 on an Airspy SDR for messing around on the lower bands. Have not been disappointed... I guess RG6 would work, IMO CO 100 or RG58 would be better.
                Good to know! RG6 or RG59 are much worst than the RG58? Because the price diference here is huge! Like the RG6 or RG59 cost R$1,20/meter - about US$0.29/meter - and the RG58 are R$3,86/meter - about US$0.96 - plus the conector that are different, I'll spend much more, so, worth it? Thank you
                T-SBCT5/T-SBCT6

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                • #53
                  For the FR24 box I use the supplied coax (H-155 I think), for my PlanePlotter box and my OGN receiver I use 10 meters of LMR-400 with N connectors at the antenna end and short N to MCX pigtails to the dongles.
                  FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                  Comment


                  • #54
                    I don't mind spending a little more for higher quality low-loss cable runs. Others here may differ, but everyone has their own philosophy...
                    F-KDAG1

                    Comment


                    • #55
                      Originally posted by F-EGLF1 View Post
                      For the FR24 box I use the supplied coax (H-155 I think), for my PlanePlotter box and my OGN receiver I use 10 meters of LMR-400 with N connectors at the antenna end and short N to MCX pigtails to the dongles.
                      Found the LMR-400 by US$10,00/meter! OMG! This one is much much much much better?
                      T-SBCT5/T-SBCT6

                      Comment


                      • #56
                        Originally posted by dudesjp View Post
                        Found the LMR-400 by US$10,00/meter! OMG! This one is much much much much better?
                        It is not the best, but in my view it offers a good performance at an acceptable price, particularly for the OGN receiver where you are dealing with signals very much weaker than ADSB, if you can keep the cable run short (1-2 meters or so) then the cable type becomes much less important, however for long runs cheaper cables can give large losses.
                        FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                        Comment


                        • #57
                          Originally posted by F-EGLF1 View Post
                          It is not the best, but in my view it offers a good performance at an acceptable price, particularly for the OGN receiver where you are dealing with signals very much weaker than ADSB, if you can keep the cable run short (1-2 meters or so) then the cable type becomes much less important, however for long runs cheaper cables can give large losses.
                          My project need about 9/10 meters of cable between the antenna and the DVB-T stick! Better i put money in this cable or by another RPi and put in the attic with then 1 meter maximum of coaxial cable?
                          T-SBCT5/T-SBCT6

                          Comment


                          • #58
                            Originally posted by dudesjp View Post
                            My project need about 9/10 meters of cable between the antenna and the DVB-T stick! Better i put money in this cable or by another RPi and put in the attic with then 1 meter maximum of coaxial cable?
                            Either use good cable OR put the Pi close OR fit an amplifier close to the antenna, once the signal is amplified then you can use almost any coax for the rest of the run as the amplifier will more than compensate for any cable losses, however it is best to go for a purpose built amplifier as the satellite ones are often of dubious quality and can be quite noisy, however you may be lucky, some people have had good results with them (I found that the one I tried was useless!).
                            FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

                            Comment


                            • #59
                              Originally posted by F-EGLF1 View Post
                              Either use good cable OR put the Pi close OR fit an amplifier close to the antenna, once the signal is amplified then you can use almost any coax for the rest of the run as the amplifier will more than compensate for any cable losses, however it is best to go for a purpose built amplifier as the satellite ones are often of dubious quality and can be quite noisy, however you may be lucky, some people have had good results with them (I found that the one I tried was useless!).
                              Yes, same here! If you look in the page 4 i put the photo of the one that i bought! But, he dind't work, without the amplifier my range are 115nm maximum, with go to 0! Don't know why! So i'm think in put the Pi in the attic and use a bigger RJ45 cable! Or find a good amplifier! Don't know what to do!
                              T-SBCT5/T-SBCT6

                              Comment


                              • #60
                                check that your aerial is open circuit if your using an amplifier. Some contain a short (just down to the way they are made) and you need to put in dc blocker at the aerial.
                                T-EGLF8

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