[BC] B.E. tuner and such...

[Ronald J. Dot'o Sr.]

Hi Tom,

Many years ago (1980's) I called you for advice (I think that you had 
just written an article on networks for Radio World) as I was about to 
do my first solo reading and adjustment of an ATU and I thank you once 
again for your sage advice which got me through the project.

The ATU in question originally had the split coil with the disk in it 
(and still does).   Somewhere along the line someone before me added a 
second coil as the input leg of the ATU and made the formerly split 
coil the output leg with a capacitor as the shunt leg.  Actually this 
station is the only one that I've encountered that has the split coil 
ATU and it's not used as such.

According to the AM-1a reflected power meter @ 1KW it has about 6W 
reflected so its got a pretty good match.  On the Gates 1 @ 1KW the 
reflected power meter (or null meter, I Idon't remember which) just 
rests on the lower peg although I know that a perfect match is not 
possible.

Thanks again!

Ron D

----- Original Message ----- 
From: "Thomas G. Osenkowsky" <tosenkowsky at prodigy.net>

> On those single coil Gates ATU's you will find that
> there is only ONE combination of taps that will
> produce 50+j0. Maybe two depending on the specific
> tower impedance and frequency. This is due to the
> mutual coupling on the coil. I once wrote a computer
> program to calculate this using a K Factor of .25
> It matched reality quite nicely. The usual rules do not
> apply as this is not really a Tee network despite how
> it appears on paper.
>
> Tom Osenkowsky, CPBE
>