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My first collinear antenna

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  • My conclusions from the tests with different DIY models of antennas is that a spider made either with only coax (no soldering) or made by soldering bare copper wires (see my posts earlier in this thread) is the easiest ones to make for the coverage you get.

    The cocos I tried to build did not perform as good as the spiders. But, they did not perform bad. Probably cocos are more sensitive to exact lengths of elements based on correct velocity factor of the cable and therefore it's hard as a "hobby antenna builder" without equipment to analyze them and get them perfect.

    Thanks first to @abcd567 and @SpaxmoidJAm and also all you others for the help and tips building the antennas. It is great fun.

    I will not stop my experiments, and the first thing I will try to accomplish is to get my antenna at a higher point to gain more coverage, but at the same time easy to reach for further antenna switches.

    Happy building to you all.

    Comment


    • I enjoy experimenting, inspite of repeated failures.

      Lately I have tried wire collinears, i.e. antennas made of bare copper wire, having multiple vertical sections with interposing phasing elements (coils or stubs).

      Yesterday I finished a wire collinear design by simulation, made the wire collinear based on dimensions from simulation. Today I put the new collinear to trial run.

      As always has happened with my collinears (made of wire as well as made of coax), the results of trial run were frustrating. Please Click Here to see the details.

      Comment


      • Hi again, I'm sticking to my best spider which I now get over 200nm with and tomorrow I will send it up about 2,5 meters higher on a pole I've been preparing. I'm expecting better coverage to my south (where it's been very poor) and probably a little better all the other directions to. I'm really excited to see the results. The inline amp will be placed right after the antenna also. I'll get back with my results. Cause as @abcd567 said:

        Originally posted by abcd567 View Post
        @FR24-BB8
        There are 3 things which give a major boost to reception: antenna height, antenna height, and antenna height.
        [emoji3]

        Comment


        • Originally posted by FR24-BB8 View Post
          I'm expecting better coverage to my south (where it's been very poor) and probably a little better all the other directions to. I'm really excited to see the results. The inline amp will be placed right after the antenna also. I'll get back with my results.
          How did it go ?


          Just to show what a cheap collinear (from Stanislav), an LNA and some (!) altitude can do:

          Screen shot 2016-10-18 at 00.52.44.png
          F-ESDF1, F-ESGG1, F-ESGP1, F-ESNK1, F-ESNV2, F-ESNV3 F-ESSL4, F-LFMN3
          P-ESGR, P-ESIA, P-ESIB, P-ESGF
          mrmac (a) fastest.cc

          Comment


          • Originally posted by MrMac View Post
            How did it go ?


            Just to show what a cheap collinear (from Stanislav), an LNA and some (!) altitude can do:

            [ATTACH=CONFIG]8106[/ATTACH]
            Hi.

            Sorry that i have not posted the results. There's been a lot of private things that has come in the way of my "antennying".
            But anyway the results was not as good as i hoped it would be, and like i said in the earlier post it got better to the south, but not much better the other directions.

            I have come to the conclusion that my biggest problem probably is altitude, the 2,5 meter increase made some improvement but is just not enough to get really good results.

            For now i just have to live with the fact that i cover around 200 nm. Here is the range plot (look back in the thread for my older plots for comparison if you like)

            rangeplot.PNG

            Comment


            • Originally posted by FR24-BB8 View Post
              Hi guys.

              I'm new at this forum, and new to FR24 to. I've just set up my Raspberry 2 to feed FR24 with data, and with the stock antenna that came with my USB-dongle I get signals from approx. 20-50 nm. Tonight I built an collinear antenna with five segments, unfortunately I can't test it until tomorrow cause I miss some connectors. Anyway, how much do you think I will increase my coverage with my 5 segment collinear vs my 67 mm stock antenna?

              Here is a my antenna assembled
              [ATTACH=CONFIG]7580[/ATTACH]
              Hi

              Because I'planning doing one like yours, I would like to know how do you connected the antenna with the cable (to the dongle).
              Do you use a conector, if yes, how? Th Inner conductor of the antenna to the shield of conector and vice versa?
              Thanks
              Regards

              Comment


              • Tried this project as my first wire collinear (see the scheme).
                I enclosed it inside a grey PVC plumbing tube (in the picture it is shown without it) and got quite disappointing results last night. After 30min testing I soon put my spider back again.
                Fyi my spider reaches 280nm from my actual position, somewhat amazing, but I hoped the collinear could give me ore range/gain.
                Instead I was getting 180nm
                Collinear-wire-adsb.gifIMG_20170507_163302.jpg
                Any suggestion?
                According to the guy who described that collinear, it should work like a charm...
                Today Im gonna make a Cantenna (66mm dia) and test it.
                Probably I will take a chance with a CoCo too.
                Last edited by perseus68; 2017-05-13, 13:15.
                Orange Pi PC Plus + NooElec NESDR SMArt + homemade 6 ele CoCo

                Comment


                • Originally posted by perseus68 View Post
                  Tried this project as my first wire collinear (see the scheme).
                  I enclosed it inside a grey PVC plumbing tube (in the picture it is shown without it) and got quite disappointing results last night. After 30min testing I soon put my spider back again.
                  Fyi my spider reaches 280nm from my actual position, somewhat amazing, but I hoped the collinear could give me ore rang/gain.
                  Instead I was getting 180nm
                  [ATTACH=CONFIG]8656[/ATTACH][ATTACH=CONFIG]8657[/ATTACH]
                  Any suggestion?
                  According to the guy who described that collinear, it should work like a charm...
                  Today Im gonna make a Cantenna (66mm dia) and test it.
                  Probably I will take a chance with a CoCo too.
                  Loops exactly those measurements? Its a super fussy design. mm accuracy type including the loop lenghts. Like, should be marked with 68mm and then meet at those points with no additional/missing
                  Posts not to be taken as official support representation - Just a helpful uploader who tinkers

                  Comment


                  • Also have a feeling my 2.0 I changed down to closer to 65mm which is nearer true 1/4 wave 1090mhz
                    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

                    Comment


                    • Well, to be honest I built the coil by wrapping the wire around a 22mm dia support. This should give a 69mm length loop which is 1/4 lambda. I saw at least 3-4 schemes like that in the web and all of them do claim 5 dBi gain.
                      I' m not sure about trying a second one at this point...
                      Orange Pi PC Plus + NooElec NESDR SMArt + homemade 6 ele CoCo

                      Comment


                      • For a wire collinear try this

                        All the technical stuff to me is unneccesary

                        For my own antenna construction I use the simple formula
                        300 divide by freq = full wave
                        300 divided by 1090 = 275 mm

                        so 1 wave = 275mm

                        3/4 wave = 206.5 mm
                        1/2 wave =137.5mm
                        1/4 wave = 68.75 mm


                        These are all the measurements you need

                        Bottom of antenna -------/////--------------/////--------------/////--------------/////-------------- Top of antenna

                        1st element = 68.75mm
                        coil = 206.5mm of wire, wound into coil 68mm long
                        2nd element = 137.5mm
                        coil
                        3rd element = 137.5mm
                        coil
                        4th element = 137.5mm

                        Add as many elements / coils as you want
                        If you put into a pvc pipe it will detune the antenna and it will be useless
                        I




                        Above antenna requires 1/4 w ground plane radials

                        https://forum.flightradar24.com/atta...1&d=1383648542

                        Name: ADSB ANTENNA.jpg
                        Views: 79
                        Size: 25.2 KB
                        ID: 3881

                        POST NO 830
                        Last edited by YWYY; 2017-05-13, 12:24.

                        Comment


                        • Thanks YWYY.
                          Sounds interesting.
                          I do understand the first segment which is 1/4 lambda but then the coils are 1/4 wave or 68mm in "linear" length.
                          The "physical" length of the coils wire is instead 3/4 wave or 206mm.
                          It is unclear to me how you can phase a 1/2 lambda section with 1/4 lambda coil (or 3/4 long wire).
                          If I look at the CoCo antenna it is composed by 1/2 lambda segments, all identical. There is no 1/4 lambda "phasing" in between them.
                          Instead, the phasing stuff is 1/2 lambda and this makes sense to me.

                          Definitely I need to study more about the antenna stuff.
                          Orange Pi PC Plus + NooElec NESDR SMArt + homemade 6 ele CoCo

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