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Purpose of end loop on FM wire antenna?

Discussion in 'Datasheets, Manuals and Component Identification' started by FuZZ1L0G1C, Jan 18, 2018.

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  1. FuZZ1L0G1C


    Mar 25, 2014
    Hi. On my hi-fi, I have the standard 'T' shape folded dipole antenna, which uses a smaller version of coax plug.
    On other receivers, I've seen just a simple single-wire extending from the set.
    However, while shopping recently, I noticed that several Hi-Fi's use a new FM antenna design - a single flexible insulated wire almost 3m, roughly 2m900 measured against my arms.
    What puzzles me is the end of all these monopoles have a small loop at the end, about 22-25mm diameter, made from same antenna wire.
    My question is:
    Does such a small loop serve any RF purpose, say 75 R impedance matching, or is it just an added convenience for hanging somewhere?
    The plug ends of the three hi-fi's I saw all used miniature female (RF?) plugs, plugging in to a male socket, no shield.
    I calculate the wire length to three-quarter wavelength of 98 MHz midpoint of FM BCB.
  2. kellys_eye


    Jun 25, 2010
    Stop you poking your eye out - seriously.
    hevans1944 likes this.
  3. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    Nice one - typical American... (I know you live in Scotland)
    I like the idea of this being for hanging the end on a nail to keep the antenna stretched.

    Definitely no HF purpose I could think of.
    davenn and hevans1944 like this.
  4. FuZZ1L0G1C


    Mar 25, 2014
    :Kicking Myself:
    What with 'flu, medication, early morning hours, my brain cell had expired.
    Realise now that I got confused with helical loading coils used on some rigs.
    I dont know about poking my eye out - I think I shot myself in the foot!! :eek:
    Head clearer today.
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