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Thread: best antenna

  1. #2001
    Captain abcd567's Avatar
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    Quote Originally Posted by trigger View Post
    My way of making a CoCo which seems to be repeatable.

    Calculate the length according to the Velocity Factor of the coax and add an extra 16mm (8mm for each end)..................
    Great! This is very helpful for all CoCo maker, new & experienced.

  2. #2002
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    Quote Originally Posted by trigger View Post
    Hi abcd, I've fixed my 12 element CoCo and added a piece of dowel to strengthen it. I'll put it back on test tomorrow. In the mean time I'll make another 12 element and if that one proves to be good too, I'll stick the 2 together
    Good, will keep you busy during this weekend.
    Waiting to see the performance of your new 2-in-1 coco , or do we call it 2-dozen coco?
    Last edited by abcd567; 2014-12-20 at 07:14.

  3. #2003
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    2x8elements.JPG

    Image1.jpg

    2x STACKED YAGIS

    Mike
    Last edited by YWYY; 2014-12-20 at 10:14.

  4. #2004
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    Quote Originally Posted by YWYY View Post
    2x8elements.JPG Image1.jpg
    2x STACKED YAGIS
    Mike
    Excellent! Gain=15.5 dBi, SWR=1.3
    Can you please provide details of connection of two antennas with one feeder?

  5. #2005
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    @Mike
    Nice build. How does it perform? From the plot it should be amazing. Are you trying to improve your range in a particular direction?

    PS you nicked the 2000th post too !
    T-EGUB1

  6. #2006
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    Quote Originally Posted by trigger View Post
    Hi abcd, I've fixed my 12 element CoCo and added a piece of dowel to strengthen it. I'll put it back on test tomorrow. In the mean time I'll make another 12 element and if that one proves to be good too, I'll stick the 2 together
    Quick update ...

    24 element CoCo is in service and working well. Range doesn't seem to have improved by much but the frames/sec on RTL1090 has gone way over 2000. I've never seen it this high before. The number of aircraft has increased too but I seemto have lost the aircraft on the ground at my local airport. I pick them up at ~1000'

    The antenna is very unwieldy. I've strapped it to a couple of bits of dowel and then pushed this into a piece of 21mm white plastic pipe. The whole thing sways about in a light breeze . I wonder how it will stand up to a gale
    T-EGUB1

  7. #2007
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    YWYY, Also curious in so far how do you connect the 2 Yagi's and deal with possible phasing issues.

  8. #2008
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    Quote Originally Posted by trigger View Post
    Quick update ...

    24 element CoCo is in service.............. The whole thing sways about in a light breeze . I wonder how it will stand up to a gale
    https://www.youtube.com/watch?v=uY-WpjPZVQY

  9. #2009
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    Quote Originally Posted by trigger View Post
    Quick update ...

    24 element CoCo is in service and working well. Range doesn't seem to have improved by much but the frames/sec on RTL1090 has gone way over 2000. I've never seen it this high before.
    Just realised that yesterday was the last Saturday before Xmas and there was a mass exodus of people from the local airports. Much more normal today.

    @abcd567 mine swings a lot more than that
    T-EGUB1

  10. #2010
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    Quote Originally Posted by abcd567 View Post
    Excellent! Gain=15.5 dBi, SWR=1.3
    Can you please provide details of connection of two antennas with one feeder?

    Hi , I spaced the beams 1.5 wavelengths - thats 275mm x 1.5 = 413mm
    The feeding harness is made with multiples of 1/4 wave ..... equal lengths from each beam
    I made mine 12 x 1/4 waves total - thats 6 x 1/4 waves from each beam
    Remember to calculate the velocity factor of the coax - I used rg58u @ vf 66%
    So
    1/4 w x .66 = 69 mm x .66 = 45 mm
    45 mm x 6 = 270 mm from the beam to the centre of the tee, overall length from beam to beam = 540 mm
    The spacing between the beams is not important, it wont alter the tuning or swr, but it will alter the gain and the pattern
    I chose 1.5 wavelengths as it gave the best gain
    Initial tests show an improved gain over the single beam

    2x8element.jpg

    Mike
    Last edited by YWYY; 2015-01-21 at 10:45.

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