Re: CB antenna mounting

["Thomas E. Francis" <tomf@domain.elided>]

Mike Klink wrote:

> Firestick or an equivalent no-ground-plane sounds like the way to go.
> Remeber, you do need special coax, though.

        Hi all,

        A common misconception concerning modile
        antennas is sheet metal providing a large ground
        place.  At the frequency the CB antenna operates
        the ground plane isn't all that effective.  Most of
        the antenna's radiation is gained through base,
        center or top loading the antenna.  The "no-ground"
        antenna is actually a 50 ohm dummy load with a
        vertical radiator - basically a 50 ohm resistor with a
        long lead on one end.

        On mobile installations at 11 meters (27 MHz), you
        could mount a magnetic mount antenna on the roof
        using a piece of sheet steel under the head liner and
        practically get the same effect as the "no-ground"
        antenna.

        Any antenna you use at 27 MHz for mobile operations
        is going to be a very real compromise.  Most of the
        radiated energy from the radio will be used up by the
        loading scheme of the antenna.

        To gain a little more efficiency, use the hood bracket
        or a trailer hitch bracket.  The effect won't be all that
        noticible at 5 watts output. but you will be a little more
        balanced.

        FYI:  I've used "no-ground" antennas in various situations
        and compared them to standard mount, mag mount and
        bracket mount - there is ZERO difference in performance.

        Later  ya'll.....

        Tom Francis (tomf@domain.elided)
        1953 IHC R-132 Dump
        1937 Farmall F-12