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My first collinear antenna

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  • @SpaxmoidJAm

    Thx.

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    • no problem the link i posted is odd number coco with a short in the end therefore its not suitable for using with inline amps (unless you use a dc blocker at the aerial).

      that velocity for the coax seems about average for rg-58
      T-EGLF8

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      • My first collinear antenna

        I'm not using an inline amp now so that should not be a problem. But I'll keep that in mind, thx.

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        • have a google for coco balun as well, its easy to add with copper pipe.

          what it does is defines where the antenna starts and the cable ends if that makes sense.
          T-EGLF8

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          • Ok, I'll do so.

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            • My first collinear antenna

              @SpaxmoidJAm

              I've just googled for coco balun and found a lot, eg that It should be 1/4 wave length. But I did not find a good enough example on measurements and so. Should I put it on the first segment or is there other things to have in mind? Could you please guide me in this?

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              • @SpaxmoidJAm
                @FR24-BB8

                Please see this interesting discussion about coco balun, but no conclusion/consensus was reached.

                http://www.eham.net/ehamforum/smf/in...html#msg870241

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                • Hi guys.

                  I've just built a coco after SpaxmoidJAm:s guide and added a copper balun with the measurements from abcd567:s link. I will mount it tomorrow, I'll let you know the result. I was really precise with the segment lengths (calculated with a VF of 85%) 116,8 mm, using a caliper. Hope it will perform nice.

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                  • My first collinear antenna

                    Btw, the last spider I built performs nearly exactly as the one before. The same range plot with filter and amp as I posted last.

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                    • Originally posted by FR24-BB8 View Post
                      Btw, the last spider I built performs nearly exactly as the one before. The same range plot with filter and amp as I posted last.
                      I dont remember which one was the "one before". If you post photos of both, it will be better. Thanks.

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                      • @FR24-BB8
                        Waiting for results of your new coco. Hope this one performs good and pays back your efforts.

                        Latest coco's & balun's photos will be appreciated and will be great help for all.

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                        • My first collinear antenna

                          Sorry for that. Photos coming up.

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                          • Here you go.

                            Here is the one before:

                            image1.JPG

                            With a range plot like this:

                            SPIDER_COPPER_WITH_FILTER_AMP.PNG

                            And here is the latest one:

                            2220544606a8ae4bf7b679620128d843.jpg

                            With this range plot:

                            Latest_Spider.PNG
                            Last edited by FR24-BB8; 2016-07-04, 08:19.

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                            • My first collinear antenna

                              Here is the coco with balun, it is a five element coco built from this guide from SpaxmoidJam http://forum.flightradar24.com/threa...5-element-coco and the balun is assembled with help from this discussion http://www.eham.net/ehamforum/smf/in...html#msg870241

                              image2.jpg

                              The balun is wider (22mm in diameter) than my pvc-pipe so it will go on the outside of it. But i will seal it with self-amalgamating tape.

                              image3.jpg

                              Thx to @abcd567 and @SpaxmoidJAm for all assistance.

                              Now i hope it perform well.
                              Last edited by FR24-BB8; 2016-07-04, 20:00.

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                              • looking good, now to see if it works.

                                Have you checked to see if the PVC is blocking RF, you can stick a small piece in the microwave for a minute if gets warm its hurting performance.
                                T-EGLF8

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