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  • Originally posted by bezeefly View Post
    The DC polarity is correct, where the centre wire of coax is connected to the power adapter's positive (+).

    The description of the amp stated:

    This is a high quality inline amplifier with up to 20dB gain. This amplifier is DC passive. For long satellite cable runs and improvement of satellite signal strength. No need for separate power supply.

    Probably the amp doesn't work at all. I've ordered another model of amp to test it.
    "No need for separate power supply"
    Because Satellite receiver supplies the DC power. The DVB-T receiver does NOT supply DC power, hence need for separate power supply & DC Combiner.

    "This amplifier is DC passive"
    It is badly written. It should be "This amplifier is DC passing" i.e. the DC applied at receiver terminal of amplifier is passed by the amplifier to the ANT terminal, so that satellite LNB also gets the DC.

    Just to make sure that your power inserter (DC Combiner) is working OK, and power is available at ANT terminal of the amplifier, do the two tests shown in the sketchs below:

    (1) With this test, you should get dc voltage at ANT terminal. If not, your power inserter (dc combiner) is defective.
    Chinese in line amplifier-test1.JPG

    (2) With this test (i.e. amplifier removed, rest as before) you should see your normal 250 km range. If not, the power inserter (dc combiner) is defective and grounding or blocking 1090 Mhz signal.
    bezeefly_amplifier-power-inserter_TEST.JPG
    Last edited by abcd567; 2014-12-25, 08:04.

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    • Merry Xmas to you too abcd567 and many thanks for all your time & patience.

      Looking forward to 2015 and trying to design the "Best antenna" for ADS-B
      T-EGUB1

      Comment


      • Originally posted by abcd567 View Post
        Just to make sure that your power inserter (DC Combiner) is working OK, and power is available at ANT terminal of the amplifier, do the two tests shown in the sketchs below:

        (1) With this test, you should get dc voltage at ANT terminal. If not, your power inserter (dc combiner) is defective.

        (2) With this test (i.e. amplifier removed, rest as before) you should see your normal 250 km range. If not, the power inserter (dc combiner) is defective and grounding or blocking 1090 Mhz signal.
        Here are the results:

        Test #1: Detected DC voltage at the ANT terminal.

        Test #2: I could see aircrafts after the amplifier removed.

        Does it mean this amplifier model is not suitable?

        Comment


        • Originally posted by trigger View Post
          I've overlaid the Heywhatsthat range from my location with the range plot from Virtual Radar Server. The blue line is 40,000' and the Orange is 30,000' This is with my 24 element CoCo. Doesn't look like I can get much better.
          I find that I regularly get hits from 50 km beyond what Heywhatsthat says, so don't think that you are necessarily limited by what it tells you. Here's my range chart. The colours are 30,000 ft and 40,000 ft as per your chart. This chart is with only one day's flights.

          rangecompare.png

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          • Originally posted by bezeefly View Post
            Here are the results:

            Test #1: Detected DC voltage at the ANT terminal.

            Test #2: I could see aircrafts after the amplifier removed.

            Does it mean this amplifier model is not suitable?
            Not necessarily. That individual piece may be defective.

            If more than one piece of that amplifier dont work with adsb, then we can say the model is not suitable.

            Comment


            • Originally posted by eastons View Post
              I find that I regularly get hits from 50 km beyond what Heywhatsthat says, so don't think that you are necessarily limited by what it tells you. Here's my range chart. The colours are 30,000 ft and 40,000 ft as per your chart. This chart is with only one day's flights.

              [ATTACH=CONFIG]5260[/ATTACH]
              Great coverage!
              Heywhatsthat.com gives a fairly good estimate of range, but may not be very precise. It also neglects trees & man made obstructions like tall buildings.

              In spite of its shortcomings, heywhatsthat.com is a very useful & powerful tool - better than being blind about what we can possibly get.

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              • Comparison of Cantenna & Spider: 24 hrs trial runs.
                No amplifier, 15 ft/5 meters cheap quality RG6 Coax between antenna & Receiver.

                Cantenna - Range Rings are 50 nm apart
                Cantenna 24 hr trial run -Dec26, 2014.jpg

                Spider - Range Rings are 50 nm apart
                Spider Antenna 24 hr trial run -Dec27, 2014.jpg

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                • Originally posted by bezeefly View Post
                  Here are the results:

                  Test #1: Detected DC voltage at the ANT terminal.

                  Test #2: I could see aircrafts after the amplifier removed.

                  Does it mean this amplifier model is not suitable?
                  I have ordered this amplifier from china through eBay to try it's suitability for adsb.
                  It is not costly, Canadian $3.66 + free shipping = Two cups of coffee at McDonalds
                  It will arrive 4 to 6 weeks from now

                  ebay order chiese amplifier.PNG
                  Last edited by abcd567; 2014-12-28, 22:44.

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                  • Characterizing the SWR of an Antenna with a Noise Source and an RTL-SDR

                    http://www.rtl-sdr.com/characterizin...ource-rtl-sdr/






                    Low cost noise generator for use with above spectrum analyzer
                    Source: http://hansvi.be/wordpress/



                    Above circuit is based on the circuit below
                    Source: http://holdenc.altervista.org/avalanche/




                    Another Noise Generator.
                    Source: http://www.n5ese.com/noise.htm





                    .
                    Last edited by abcd567; 2014-12-30, 19:46.

                    Comment


                    • Originally posted by SpaxmoidJAm View Post
                      same ebay shop has one of these,

                      http://www.ebay.com/itm/3MHz-1200MHz...item35dba96a53

                      you will need this to do your tuning. You can get directional couplers from many places

                      watch this video (the first i found) you could in theory use the DVB-T dongle as the spectrum analyser this would then allow you to tune aerials.
                      https://www.youtube.com/watch?v=zVeAGy0LQow

                      Food for thought for doing this at home myself.
                      I mentioned this a while back and having a quick look on ebay found this http://www.ebay.co.uk/itm/RF-Signal-...-/201247775512

                      that with the coupler and a SDR dongle is pretty good setup.
                      T-EGLF8

                      Comment


                      • Originally posted by SpaxmoidJAm View Post
                        I mentioned this a while back and having a quick look on ebay found this http://www.ebay.co.uk/itm/RF-Signal-...-/201247775512

                        that with the coupler and a SDR dongle is pretty good setup.
                        What I am aiming at is dirt-cheap equipment. Spectrum analyzers, sweep frequency/noise generators, directional couplers are readily available, but cost? thousands of dollars.

                        (1) Spectrum analyzer is the costliest item, costing several thousand dollars. Now free of cost software in combination of $10 DVB-T stick can act as spectrum analyzer.

                        (2) Directional coupler from China are available on eBay for around $25.

                        (3) Noise generator are available for $13, but these are for audio. I found 5-2150 MHz range for $193+shipping http://www.tequipment.net/AppliedInstrumentsNS-1.html.
                        The one in the circuit diagram posted in my previous post can be built for less than $10 (check prices of transistors & diodes on eBay: $1 to $2 + free shipping for 10 pieces of each of these transistor & diode from china).

                        Comment


                        • Another cheaper model from China, $62.87+Free shipping:

                          138MHz-4.4GHz USB SMA signal source/signal generator/simple spectrum analyzer
                          http://ebay.com/itm/111527659749

                          138 Mhz-4 Ghz Signal Henerator.jpeg

                          There is another one, costlier but something additional, noiise generator? tracking? dont understand. $81.67+free shipping:

                          138M--4.4G SMA signal source,generator,simple spectrum analyzer +Tracking source

                          http://ebay.com/itm/121505970363


                          [ATTACH=CONFIG]5301[/ATTACH]

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                          • the tracking part means that when you are doing a frequency sweep the listening part is triggered at the same time, basically its synchronised. You get a real time (well at that time) display rather than analysing the entire sweep.

                            the only thing you should have to add to that (second link) is the directional coupler and your aerial.
                            Last edited by SpaxmoidJAm; 2014-12-31, 09:43.
                            T-EGLF8

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                            • @SpaxmoidJAm
                              Thanks for detailed info. What is needed to display the real time sweep/spectrum? An oscilloscope or DVB-T Stick with spectrum software?

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                              • Happy New Year to the "Best Antenna" gang.

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