Cecil Moore wrote in message ...
Brian Kelly wrote:
In the case of your 110 foot flattop with it's 110 foot feedline and
for my specific purposes the "tuner" would be a pair of inline lo-loss
fixed coils with taps which are selectable with a simple two pole
two-position ceramic rotary switch. Or make it a three pole switch and
be able to ground the antenna. Three taps yields three slices, etc. A
tuner like that would be a whole bunch easier to build and use and
would require much less mechanical claptrap than the original pair of
variable caps scheme requires.

It's essentially moving the loading coils from the antenna to the
hamshack

That's OK, High Q loading coils are not necessairily bad things at
all. A couple decent-size airwound coils are *much* easier to come by
in the shack than they are up in the air and out in the weather. Plus
you can vary the L right in the shack.

and, according to EZNEC, gives a 1.1:1 SWR from 3.6 to
4.0 MHz. SWR goes up to 1.5:1 on 3.5 MHz.

I could definitely live with that.

However if using your 110 foot run of ladderline and coils
configuration is a hassle but a 44 foot feedline would work Mr.
Boyle's design can be used to get the same basic performance results
with the caps. The thread has produdced a couple good approaches for
practical solutions for an old problem and they both go into my
keepers book.

It will be interesting to apply Mr. Boyle's design to your particular
two-segment problem.

I'm not far enough along my modeling learning curve to be able to
model transmission lines yet but you're obviously right.

Assuming some full system modeling of the Boyle Special for basic
guidance, the availability of a 259B, another ceramic rotary switch
and a pile of silver mica caps what are the downsides of using fixed
caps vs. variable caps?

w3rv