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  • Originally posted by hikeofyourlife View Post
    ........ I made up a PCB dipole antenna as well and even though it's sloppily cut with a Dremel and utility knife, it does almost as well as the CoCo!
    That is great news for those who failed to get good results from their DIY CoCo.

    It will benefit all forum members if you post photos of your PCB dipole, with dimensions & tips/instructions for making it. A coverage plot screenshot will be added advantage.

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    • Poor results!!




      [/QUOTE]

      Is that a shorted top? Otherwise everything looks right and I don't know why that isn't working.

      In my experiments I couldn't find a difference between shorting a half-wave section on top and shorting a 1/4 wave section with 1/4 wave whip on top but leaving the top open didn't work well at all

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      • Originally posted by hikeofyourlife View Post
        Is that a shorted top? Otherwise everything looks right and I don't know why that isn't working.

        In my experiments I couldn't find a difference between shorting a half-wave section on top and shorting a 1/4 wave section with 1/4 wave whip on top but leaving the top open didn't work well at all
        (1) My CoCo do not have 1/4 wave at top.
        (2) The top is open.
        (3) I will add a 1/4 wave shorted top and give it a try.
        (4) I am now doing 2nd trial run of sleeved coco with 114mm long coax inside the sleeve.

        This time I will run it at least 12hrs or preferably 24hrs, as 1 hr quick trial is not enough for a conclusive opinion.

        Even 24hrs trial may have to be repeated another day to eliminate weather factor.
        Last edited by abcd567; 2014-11-12, 00:35.

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        • Hey guys,
          I'm planning to get an amplifier for my antenna. I have a PCB antenna from jetvision.de plugged into my raspi/router/openwrt.
          I'm looking to buy this powerinjector + supply, this amplifier and this DC blocker.

          Question:
          1. could this improve my reception?
          2. do I need 2 DC blockers? One to protect my DVB-T stick and one to protect the antenna? Or only one, to protect the DVB-T stick?

          Comment


          • Update of Sleeved CoCo's Trial Run - Interim (8 hrs results)

            Last night after starting the 24 hr trial run of sleeved coco, I checked my benchmark antenna & found it is showing 70 to 100 nautical mile more range than normal in most directions. This indicated exceptionally favourable weather & atmospheric conditions. I therefore discontinued coco's trial.

            In morning at about 9:30am, I noted that the benchmark antenna is now showing normal range. I started trial run of sleeved coco.

            At 5:30pm (after 8 hrs trial run) I took a screen shot, which I am posting below. It is not so bad as the 1 hr quick trial had shown.

            Test is still continueing, to complete 24 hrs.

            Interim (8 hrs trial) range plot
            Screenshot_2014-11-11-17-43-03.png

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            • Originally posted by loplo View Post
              Hey guys,
              I'm planning to get an amplifier for my antenna. I have a PCB antenna from jetvision.de plugged into my raspi/router/openwrt.
              I'm looking to buy this powerinjector + supply, this amplifier and this DC blocker.

              Question:
              1. could this improve my reception?
              2. do I need 2 DC blockers? One to protect my DVB-T stick and one to protect the antenna? Or only one, to protect the DVB-T stick?
              I use the same type amplifier on my CoCo and it definitely gets more range, like 40-50 miles, plus my plane counts jumped from around 1500 per day to 2100. I think a PCB could benefit from it for sure. especially if you have a longer cable run and/or lossy cable. (My biggest problem lately has been crummy crimp connectors on my cables, they tend to go bad easily if you're connecting/disconnecting a lot as you experiment) You don't need that DC blocker, the power injector already has one built in. If you switch to a coaxial collinear some day you would need the DC blocker between the amp and the antenna, however.

              Comment


              • Originally posted by loplo View Post
                Hey guys,
                I'm planning to get an amplifier for my antenna. I have a PCB antenna from jetvision.de plugged into my raspi/router/openwrt.
                I'm looking to buy this powerinjector + supply, this amplifier and this DC blocker.

                Question:
                1. could this improve my reception?
                2. do I need 2 DC blockers? One to protect my DVB-T stick and one to protect the antenna? Or only one, to protect the DVB-T stick?
                1. Theoretically... it should boost signal strength - but it will also boost noise, and I see you are using an DTV dongle - these are very susceptible to noise AND out of band signals.
                Only by trying one will you know, as this will vary from location to location.

                2. Does your antenna present a short circuit to the feeder ? If NOT then only one isolator is needed... you can test this with a multimeter if no diagram of the antenna is available.

                Comment


                • Originally posted by loplo View Post
                  Hey guys,
                  I'm planning to get an amplifier for my antenna.......
                  Question:
                  1. could this improve my reception?
                  Yes, it will improve max range & number of planes.

                  2. do I need 2 DC blockers? One to protect my DVB-T stick and one to protect the antenna? Or only one, to protect the DVB-T stick?
                  (a) The power inserter blocks dc towards receiver (DVB-T stick). You don't need any other dc blocker for receiver.

                  (b) The power inserter passes dc to amplifier, and amplifier passes dc to antenna. If your antenna has a short, you need a dc blocker between antenna and amplifier.

                  I personally prefer to insert a dc blocker between antenna and amplifier, even if antenna is not shorted. The blocker does not do any harm and protects the system from accidental short.

                  As rooster has mentioned, you can check weather or not your antenna has a short by a multimeter.
                  Last edited by abcd567; 2014-11-12, 06:06.

                  Comment


                  • If after making a coco, one find it is not working good, one can't fix it. He has to discard it. This is a normal situation in DIY coco.

                    If this happens with twin-lead compensated coco, one does not have to discard it. Performance can be made good by adjusting length of twin-lead.

                    The main beauty of twin-lead compensated coco is that it is adjustable by simply sliding the feeder coax a few mm towards or away from coco.

                    The drop in performance caused by inaccurate VF or not-so-good workmanship, is largely compensated by adjusting the twin-lead length, and one does not have to discard the coco.

                    Comment


                    • Thanks guys for your input.
                      Parts ordered, I'll report back when they've arrived and I have my first results.

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                      • Do we have any ideas or plans for a Directional antenna ??

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                        • Originally posted by HermanZA View Post
                          Do we have any ideas or plans for a Directional antenna ??
                          How directional do you want it ?

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                          • 120 degrees or less.

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                            • May be Yagi?

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                              • Thinking to put up a directional antenna, but would like a wide'ish kind of coverage area, not a narrow 12degree kind of thing. This of course would be rather handy to have as a 2nd antenna and feeder to "spot cover" important areas like airports.

                                Hit up my old buddy Goooooogle last night, got a few ideas, but no exact How-To's for a Yagi.

                                Found this one, which clearly is an easy to do DIY project....
                                ADS-B_8EL.JPG
                                ... but how he does his active element and the cable connections are not clear.

                                The calculations for the element lenghts are easy....
                                If this calculator is still accurate at 1090mHz, then its a breeze.
                                http://www.k7mem.com/Electronic_Note...vhf_quick.html

                                An 12 element Yagi with a +- 35degree beam will give +- 12dB gain and be about 630mm in length. But the finer art of how to build and connect those bits, that is the problem!
                                Last edited by HermanZA; 2014-11-14, 07:47.

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