Topband: ground rod replacement ?

[Bruce]

Hi Bob,

There are still old wives tales out there.

This one is easy to dispel. Put up a one wire un-terminated Beverage about
300 -400 foot long and maybe higher than 5 feet above ground (with a 300-350
ohm to 50 ohm matching transformer).
Check the VSWR from 1.8 MHZ to about 10 MHZ.  You may find a resonance but
not a flat
self termination.  Then drop the wire to the earth for the entire length and
re-test.  Above a given frequency self termination will take place.
(Depending upon your matching transformer it could go up to 50 MHZ. All with
the same wire, same everything.  Velocity factor change, (capacitance to
ground), the wire resistance is not the main influence.

(It may be a way to get a high power dummy load.  Bury the BOG wire, coax,
and feed with a shielded antenna tuner.)

TNX
73
Bruce-K1FZ




> I have been preaching for years against the sometimes-expressed "the
> longer the better" myth.
> Your "frequency at which self termination takes place" surprises me.  I
> had
> always assumed it was due to out and back losses along the wire causing no
> reflected signal to arrive back at the Tx.  But I never played with it for
> frequencies higher than 2 MHz or with wire longer than two or three
> wavelengths.
> Thanks again.
> Bob VE7BS