A couple comments. First off, the thing can be tuned from the shack with
an "unbalanced openwire" feed, simply a wire carefully insulated from
earth with, ideally, a number of parallel wires under it in or on the
ground. Needless to say this will put a LOT of high voltage where people
and pets might get hurt, but it will work and will not suffer the losses
of a piece of RG-213.
HOWEVER
To run it on 160 and 80 seems require such a simple matching system that
I fail to see why one would do much else. A coil to ground, the size of
which will set the resonance of the vertical, with a tap on it which will
allow you to select the "50-ohm" point will get you all that the antenna
and ground that you have can do. You'd need to switch the coils and taps
to change bands, and perhaps even within the bands, but that all seems
very easy to do with little loss. The greatest problem will be dealing
with switching if really high power is involved, wien one might expect
5-10KV on the base of the vertical.
Why do they sell these things??? I don't know, but I bought one back in
1960 while in high school. Then...it was called a "Gotham Vertical" and
I don't think I'll ever forget the "I've been had" feeling when the box
was opened and my $19 purchase consisted of 23 feet of aluminum tube,
4 conduit clamps, and a piece of coil stock (not B & W). No magic box,
no free lunch, no nothin' special. But...I sure did learn a lot from that
vertical, and made a lot of contacts.
Ralph Matheny
K8RYU
207 Gibbons Place
Marietta Ohio 45750
mathenyr@marietta.edu
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