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  • Answer for Bill

    From The Other John@21:1/5 to All on Thu May 19 14:28:24 2022
    Follow up to my aerial problem.
    The slack 40+ year old coax drapes down the wall and goes through a hole
    into a built-in cupboard in bedroom 1 where it's plugged into a passive splitter which feeds bedroom 4 (computer room) and downstairs to lounge.
    I have an indoor aerial bought long ago for a portable TV. It's in the
    form of a halo - circular plastic ring holding a metal ring with a gap at
    the bottom where the coax is connected. It has a fold out stand at the
    bottom. I wondered if having a bottom feed would make it horizontally polarised like a folded dipole but plugging it into the splitter and
    scanning the output in the lounge revealed it's happy with Reigate's VP TX
    and the level of UHF channels 23 and 24 are much better than with the
    yagi, see:

    <https://www.dropbox.com/s/5s1a0pjjeae26kt/ Scan%20468.0-592.0MHz%20indoor.png?dl=0>

    So I don't need a new aerial after all. :)

    --
    TOJ.

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  • From David Woolley@21:1/5 to The Other John on Thu May 19 17:45:25 2022
    On 19/05/2022 15:28, The Other John wrote:
    It's in the
    form of a halo - circular plastic ring holding a metal ring with a gap at
    the bottom where the coax is connected. It has a fold out stand at the bottom. I wondered if having a bottom feed would make it horizontally polarised like a folded dipole

    If the feeder is simply connected across the gap in the loop, with
    nothing else there, it is probably being fed against the braid of the
    cable, i.e. the cable outer is actually part of the aerial. That might
    well result in significant vertical polarisation, whereas, if there were
    a true balanced feed, it would have to be horizontal.

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  • From The Other John@21:1/5 to David Woolley on Thu May 19 18:15:12 2022
    On Thu, 19 May 2022 17:45:25 +0100, David Woolley wrote:

    If the feeder is simply connected across the gap in the loop, with
    nothing else there, it is probably being fed against the braid of the
    cable, i.e. the cable outer is actually part of the aerial. That might
    well result in significant vertical polarisation, whereas, if there were
    a true balanced feed, it would have to be horizontal.

    There's a plastic box in the base where the cable comes out so it might
    have a balun built in.

    --
    TOJ.

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