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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

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    • 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?

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      • 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.

                Comment


                • 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,



                    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.
                    Use a RF sweep generator, a directional coupler, and a spectrum analyzer to tune a 2.45 GHz antenna.The directional coupler is RF Power SDC-202-302-R1-8 and ...


                    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


                        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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                              • Happy New Year 2015 !!

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