Topband: Inverted L improvements - Part 3 (now with data)

Guy Olinger K2AV k2av.guy at gmail.com
Wed Jan 23 02:04:51 EST 2019


What is missing from that discussion about a maximized use of a given
investment, is whether that investment however well maximized, is in fact
adequate for the particular ground characteristics and circumstances.

Four rotten eggs will deliver a rotten omelette no matter what you mix in
or how neatly it’s served up.

In seriously poor ground, the total copper in the radials needs to be
enough for full size, dense and uniform all around. A maximized inadequate
is still inadequate.

Sparse, undersized, or irregular ground radials do not do it for poor
ground.

His results with shorter radials suspiciously point to poor ground or
perhaps a local loss issue not yet identified.

He inserted a K9YC design choke at feedpoint and his R went up, indicating
that the earlier measurement was lowered by something shunting down the
true R of the radials.

73, Guy K2AV

On Tue, Jan 22, 2019 at 10:31 PM Chortek, Robert L. <
Robert.Chortek at berliner.com> wrote:

> Exactly!
>
> Sent from my iPhone
>
> > On Jan 22, 2019, at 7:25 PM, Grant Saviers <grants2 at pacbell.net> wrote:
> >
> > Al Christman K3LC thoroughly sliced and diced the tradeoffs of number vs
> length for given total wire investment is his Mar/Apr 2004 NCJ paper.
> >
> > N6LF also has a lot to say.
> >
> > Grant KZ1W
> >
> >> On 1/22/2019 16:11 PM, Chortek, Robert L. wrote:
> >> “Wes cut his radial length to match the vertical L section height (see
> N6LF
> >>> reference).  He didn't reduce the number of radials.”
> >> I didn’t think it was the “shortening” OF the length of the radials
> that would improve performance e.g. going from 10 125’ radials to 10 55’
> radials (in the case of a 55’ vertical); rather, it was the fact that 10x
> 125’ of wire could be better employed to increase the number of radials,
> albeit resulting in shorter radials, that decreases the ground loss (since
> most is nearer the base of the vertical).  If I’m correct, then shortening
> a given number of radials should decrease loss or improve performance....
> >> 73,
> >> Bob AA6VB
> >> _________________
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> Reflector
> _________________
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>
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