Discussion in 'Amateur Radio News' started by Guest, Jan 15, 2001.

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  1. Guest

    Guest Guest

    HA5CMG, Charlie writes "You can increase Radiation Efficiency (while reducing number of turns on your fixed centerloaded antenna coil or on the "screw driver" type of antennas) by installing a Top-Hat-Loop on your whip.

    From a welding supply buy half of dozen 1/16" dia. stainless or berilyum copper welding rods.

    In the vise or with a visegrip hold the top of the whip and the 1/16" dia. ss rod wind it around the whip 7 or more times tightly, the move down on the whip 6" or more grip them together, forming a loop, wind the ss rod tightly on the whip. Do this with minimum of three rods.
    Now you have a theoritical phasare about 6-12" diameter, depends on how much of the 3' ss rod you have used up.

    Proof of how well it works, count the number of the turns you are using on 80 M or 40M. Versus before the Top-Hat-Loop installed.
    Note this will effect the 10M band due to the effective lenght of the whip is now much longer.

    References in ARRL Antenna Handbook, page 16--1 to 16-15
    Pix available for the asking.

    Best 73's and have a gret mobile-ing Day.

    Check out my website.

    Charlie, VE7BOC/W6 (HA5CMG)

    <A HREF="">
    Stealth Antennas</A>"
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