Re: NEC-LIST: Broadband VHF Whip

zvi frank wrote:

> Hi Everybody,
>
> Has anybody got any ideas on making a VHF whip 50 cms long with a
> bandwidth from 30 to 88 MHz. It seems to me a tall order? Thanks in
> advance,

You didn't say what the efficiency (gain) characteristics should be.
One can certainly make an antenna perform over a wider frequency range
by introducing loss (resistance) at the feedpoint and/or in the
antenna element(s) itself.

Another technique is to design a matching network using capacitors,
inductors, transformers, and transmission line sections that function
with the antenna to provide the broadband operation. The antenna
could also be made to operate over a wider frequency range by wrapping
a helix around a ferrite rod.

The frequency range cited is a tactical U.S. military VHF band used
principally by the Single Channel Ground and Airborne Radio System
(SINCGARS). End-fed and center-fed vehicular and airborne whips exist
to support the frequency-hopping SINCGARS radios but they are longer
than 50 cm. There are blade-type airborne antennas that fall within
this height. For example, Chelton, Inc., Lewisville, TX, makes
low-profile blade antennas for the SINCGARS band that have heights of
less than 10 inches.

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