[TowerTalk] Re: linear loading

Guy Olinger, K2AV k2av@qsl.net
Tue, 17 Nov 1998 22:29:01 GMT

On Mon, 16 Nov 1998 10:20:50 -0500, "w8ji.tom" <w8ji.tom@MCIONE.com>

>Third, the last thing you want to do is put capacitance across a loading
>inductance (and the stub in a linear loading system is simply an inductor
>with very poor form-factor). Capacitance shunting an inductor reduces
>efficiency by increasing unwanted circulating currents in the inductor (and
>stub). Linear loading always has a lot of shunt capacitance, just like some
>poorly designed coils (and all traps) do. 

How would you comment on the spread-out variant of LL used by Force
12. That would seem to minimize capacitance, particulary in what
remains as the "stub" which is a couple feet apart on the 40m design.

>It has been my experience, based on direct FS measurements, that properly
>designed lumped loading is better than linear loading when the loading is
>at the same effective location on the elements and similar conductor sizes

What is the "best" effective location for the loading, other than at
the ends? What is the effective location for the loading on the F12

>are used in the loading systems, but this difference is so minor you'd
>never notice it.
>IMO, seeing a large difference means something was wrong with the design of
>the poorer system rather than the fact the loading "method" was changed.

Or the sensitivity of a standard setting on an LL antennas to
environment, placement, etc, making setting up in the field

>73 Tom

Guy L. Olinger
Apex, NC, USA

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