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Thread: best antenna

  1. #2481
    Captain abcd567's Avatar
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    Quote Originally Posted by Furt1veOne View Post
    abcd567, wanted to say thank you for all the info you have posted on this thread. I read about half of the 248 pages. I made a spider based one with eight legs made from #6 copper I had laying around and some 2mm copper around the f connector in a 1" circle. I get 150nm out of it without any amp or capicators for tuning. Going to try and make another one tomorrow with a larger circle around the f connector for a larger ground plane. Also, thanks for all the tutorials in setting up the Raspberry Pi. Came in really handy when starting yesterday.
    I'll post a picture later once I have my four posts.


    Sent from my iPhone using Tapatalk
    Happy Experimenting! Waiting for pictures.

  2. #2482
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    Thanks again abcd. I've used most of your walk throughs to get everything started working as well.

    I made a Dr Pepper antenna and this one seemed to have greater range. Using the whatsupthere website, I seem to be reaching close to my limits with it.

    Have the second one like this close to being done with the larger ground plane.



  3. #2483
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    Pretty nice work and decent soldering, Furt1veOne!

  4. #2484
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    Thanks HermanZA. Hard soldering copper that's 4mm. Ended up having to use a propane torch to heat it up.

  5. #2485
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    Yeah, I know. Thats why my effort to make one, did not work out so good.

  6. #2486
    Captain abcd567's Avatar
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    @Furt1veOne:
    EXCELLENT! Very neat and crafty. you got very good soldering skill.
    I cannot solder as good as you. That is the reason I never attempted to make a Spider using soldering. Always used nuts & bolts to fix wires in position.

  7. #2487
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    Helical Antennas

    Am I right in believing the wave length of 1090 MHz is 10.83302752293578 inches?

    If so, is there any benefit of constructing a Helical full wave antenna? Reason for asking is that I have seen full wave WLAN Antennas (2.4GHz) like the one shown in the 1st image and there is an excellent example of one with 4 antennas on the Radar Tracking Station in France as shown in the 2nd Image..

    Has anyone any experience of building one or testing one?


  8. #2488
    Purser Rooster's Avatar
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    Am I right in believing the wave length of 1090 MHz is 10.83302752293578 inches?
    Yes... BUT that is full wave, the majority of antennae work on half wave - often centre fed (two quarter waves)

    The antennae in your pix are highly directional (as well as circularly polarised) so little use to us I'm afraid.

  9. #2489
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    Quote Originally Posted by Rooster View Post
    Yes... BUT that is full wave, the majority of antennae work on half wave - often centre fed (two quarter waves)

    The antennae in your pix are highly directional (as well as circularly polarised) so little use to us I'm afraid.
    Hi Rooster, that is true if being used in the axial mode, I was more thinking like the WLAN Antenna in the image that is Omnidirectional as it is being used in the normal mode...

    In the normal mode or broadside helix, the dimensions of the helix (the diameter and the pitch) are small compared with the wavelength. The antenna acts similarly to an electrically short dipole or monopole, the radiation pattern similar to these antennas is omnidirectional, with maximum radiation at right angles to the helix axis. In most cases, helical antennas are mounted over a ground plane. The feed line is connected between the bottom of the helix and the ground plane and are used for compact antennas for portable and mobile two-way radios etc.

    I just wanted to be sure of the wavelength of 1090MHz as I want to start playing with some ideas on a home made Antenna that is small, light, easy to use indoors, in a fixed location or maybe a car and the I think the Helical (not to be confused with spiral) would be ideal..

    The large Radar Tracking Helical in picture 2 is directional as its axial and for that specific purpose (I am not sure what the neighbours would think if I had one in the Garden LOL) but I was toying with the idea of making a scaled version to work in the normal mode with a 4 Antenna array and see what results I get.

    Obviously the Antenna experts will come along and tell me why its a bad idea, but I just wondered if anyone had experience of them or had tested a design?

  10. #2490
    Captain abcd567's Avatar
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    Has anyone seen this site?

    http://global.adsbexchange.com/Virtu...r/desktop.html (ZOOM OUT TO SEE WHOLE OF NORTH AMERICA AND EUROPE)

    http://www.adsbexchange.com
    .
    Last edited by abcd567; 2015-10-28 at 17:13.

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