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My first collinear antenna

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  • #46
    That's a great idea - And a good way to ensure consistent results each time one is constructed.

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    • #47
      My first collinear antenna

      Thx guys. Yeah, i figured it'll help me. Cause I'm not a soldering God.
      Tomorrow I'll try to build two of them, like abcd said. One with the radials bent just at the edge of the washer and one with radials going horizontal 20-25 mm before bending them. Then I'll gather some data and compare them.
      I'll let you know the result, and post some range plots.
      Last edited by FR24-BB8; 2016-06-10, 23:12.

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      • #48
        My first collinear antenna

        Here's a tip how to straighten wires. I recently bought copper wire packaged in a roll, and when I cut the the pieces to my needs, they all was crumbled and not straight. But after giving the wire a treatment like this, it not only got straight, it also got a bit more rigid.

        https://vimeo.com/21121153

        Thx to the person posting this video.
        Last edited by FR24-BB8; 2016-06-10, 20:56.

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        • #49
          @FR24-BB8:
          Happy Experimenting!
          Waiting for your results.

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          • #50
            why would you want to stress the wire by putting that many twists in it???? asking for trouble.

            just put one end in a vice and the other in a pair of pliers ( or two pliers one each end) and pull it, bingo strait wire without being stressed to badly and twisted to f......
            T-EGLF8

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            • #51
              My first collinear antenna

              @SpaxmoidJAm

              I know i can straighten them with pliers. But they never be as straight and rigid like when doing this.

              The wire is going to be used as radials on a spider antenna, they'll be about 85 mm long I can't see that it will affect it negative. Of course I wouldn't do this on regular cables.

              Anyway, what do you mean are the troubles/disadvantages? Will it be bad reception, lousy range? If so, I certainly won't do like this.
              Last edited by FR24-BB8; 2016-06-11, 10:44.

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              • #52
                Originally posted by FR24-BB8 View Post
                @SpaxmoidJAm

                I know i can straighten them with pliers. But they never be as straight and rigid like when doing this.

                The wire is going to be used as radials on a spider antenna, they'll be about 85 mm long I can't see that it will affect it negative. Of course I wouldn't do this on regular cables.

                Anyway, what do you mean are the troubles/disadvantages? Will it be bad reception, lousy range? If so, I certainly won't do like this.
                BB8,
                I would agree with SpaxmoidJAm, stressing the wire in this way could easily cause microscopic fractures, particularly where you introduce any bends, if you are using this outdoors then the fractures could allow corrosion to start and you may find the radials dropping off or breaking where they are bent after a few months, just pull the wire straight without twisting it, there is nothing to be gained by trying to stiffen it as it should have plenty of stiffness if it is thick enough, however if this is for indoor use then it should do no harm, just don't over twist it or it may crack when you bend it.

                Also if you are thinking of trying again with a collinear then probably the best diagram is on the following page:
                http://f5ann.pagesperso-orange.fr/An...ire/index.html
                Unfortunately the designer of this François (F5ANN) died a few days ago, he was the designer of the well known 'Active Diapson' antenna so any design of his is probably as good as it gets, just be sure to use exactly the same type of co-ax unless you are happy re-calculating all the lengths.
                Last edited by F-EGLF1; 2016-06-11, 16:30.
                FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

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                • #53
                  Ok thx.

                  We will see if my radials fall off

                  And thx for sharing the link.

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                  • #54
                    Here is My first variant. Not the best soldering but. I'll sealed the connection to the F-connector with glue, so I will not install it until tomorrow.

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                    • #55
                      Looks very nice! Waiting for results.
                      Which glue you have used? In my prototype, I was considering use of either hot melt glue, or epoxy resin (araldite+hardener), but did not apply any as I cannot install outdoors. I live in an apartment, with no balconies.

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                      • #56
                        My first collinear antenna

                        Originally posted by abcd567 View Post
                        Looks very nice! Waiting for results.
                        Which glue you have used? In my prototype, I was considering use of either hot melt glue, or epoxy resin (araldite+hardener), but did not apply any as I cannot install outdoors. I live in an apartment, with no balconies.
                        I used a two component epoxy bought at a local hardware store. It says 5 min, but it's late here in Sweden so I'll get a nice sleep and let it harden until tomorrow.

                        Last edited by FR24-BB8; 2016-06-11, 21:31.

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                        • #57
                          Yes, that is what I meant by "Araldite", which is a brand name. The generic name is epoxy resin+hardener. I have been using araldite for a long time, that is why I mentioned it.

                          standard_24ml_GBpackaging_white.gif .sku_5376_1.jpg




                          In 1983 a visual stunt presentation was set up to show the strength of Araldite by gluing a yellow Ford Cortina to a billboard on Cromwell Road, London, with the tagline "It also sticks handles to teapots". Later, to demonstrate more of its strength, a red Cortina was placed on top of the yellow Cortina, with the tagline "The tension mounts". Finally, the car was removed from the billboard, leaving a hole on the billboard and a tagline "How did we pull it off?.

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                          • #58
                            i'm mean really pull on the wire it stretches a little and goes dead strait, there will be no effect on performance which ever way you do it.

                            the only problem i can see doing it with a drill is it mechanically weakening the wire (stretching and twisting it beyond it elastic properties and becoming brittle) but as this is for an antenna no problem, i just consider it a bad way of doing it.
                            Last edited by SpaxmoidJAm; 2016-06-12, 06:53.
                            T-EGLF8

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                            • #59
                              @FR24-BB8
                              While comparing different antenna models, it is more convinient to install them at an easily accessable location like a window or balcony. This saves frequent use of a ladder and climbing on roof. After the comparison is done, and you have found which antenna performs best, you can mount it on roof.

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                              • #60
                                @abcd567

                                Yes, i have mine easily accessible outside, not on top of the roof, which unfortunately give me bad range to the south to. Maybe I mount it higher when I'm finished experimenting.

                                Regarding my new spider, I mounted it an hour ago, but Scandinavian Airlines pilots are on strike since Friday here in Sweden. This means a lot of cancelled flights and almost no flights around here, so no feeling yet about the result. But other companies fly over here to, so after a couple of days I have some data to compare.

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