On 7/12/2013 2:40 PM, Richards wrote:
On 7/12/2013 4:29 PM, Stuart Rohre wrote:
To further amplify Rick's comments, an antenna that has gained
popularity in USA in recent years, is a 40 odd foot high vertical for 80
and 160m work. One of our North TX hams published his versions in
two QST articles.
The "magic" (good engineering) behind the 43 ft vertical antenna is that
it is not too close to a half wave, or multiple of half-waves, on the
major ham bands, so the feedpoint impedance never gets TOO high, and
it's long enough (roughly 3/16 wave) on 80M to load and radiate fairly
well.
In contrast, Rick sold me on the notion that an 80m inverted-L with
appropriate additional capacitance is better than a very short
vertical with inductive loading. (Hopefully not losing too much in
such a short translation...)
He is exactly right. To understand the design concepts, study my 160M
antenna presentation, on my website, dividing the physical dimensions by
2.. The ON4UN book also has lots of good stuff on verticals and radial
systems.
http://k9yc.com/publish.htm
73, Jim K9YC
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