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[TowerTalk] Force 12 Sigma 80 (and alternatives)

To: <>
Subject: [TowerTalk] Force 12 Sigma 80 (and alternatives)
From: (
Date: Sun, 10 Feb 2002 18:53:09 -0600
I'm not sure I agree that a base loaded 35 ft 80M vertical 
with a good ground system "would work nearly the same
as a full size antenna" as W8JI suggests.

My friend KZ4V had an HF2V vertical which is 
essentially base loaded on 80M with 120 radials
(exact length unknown but at least 30 ft) that worked
very well on 40M but SUCKED on 80M where she had
to struggle in pileups to work DX.

A vertically polarized Delta Loop and Inverted Vee, with 
apexes at 90 ft each were MUCH more effective when 
installed a few years later.  I expect a TOP loaded vertical 
would also be much more effective than a base loaded vertical

The MFJ 1792 80 / 40 vertical is one reasonably priced option
which is full size on 40M with an isolating coil and top hat 
for Top Loading on 80M and priced around $160.

Another option is to shunt feed a short tower / Yagi combination
or use my Elevated GP approach shown in JUNE 1994 QST or
the ARRL Antenna Book and Handbook which uses a Yagi as
a Top Load for an 80M GP.

Tom N4KG

On Mon, 21 Jan 2002 "Tom Rauch" <> writes:
> > Have any readers had experience with Force 12 Sigma 80???  I am
> > considering a vertical due to small lot and dissatisfaction with 
> my inverted vee for DX. The info on F 12's site looks interesting but
> > $600 for a 80M vertical !!!! WOW.  Opinions??
> Why not just build a vertical Brad? 
> While linear loading is generally not as efficient as lumped loading 
> using properly designed inductors or a small capacitance 
> hat/inductor combination, you'd almost certainly never notice the 
> difference (expect perhaps in a yagi). By far the bulk of losses are 
> generally in ground systems, so concentrate on a good earth 
> ground. If you have a really good ground system, a 35 foot base 
> loaded vertical would work nearly the same as a full size antenna!   
> If you could just erect a 30-40 foot push up mast, and make 
> guylines to the top load the mast, you could have a really nice 
> broad-band and efficient vertical for less than $100.
> Another choice is the 80/40 meter MFJ vertical. While it is narrow 
> banded on 80, but works quite well. It is top loaded and about 34 
> feet or so high. You could also modify it and make a better 80 
> meter antenna out of it by using a larger "hat" at the top.

> 73, Tom W8JI
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