[BC] Carl Smith method of dual ground system

[Jerry Mathis]

On 2/12/06, Alan Alsobrook <radiotech at bellsouth.net> wrote:
>
> This is a picture of a station in South Fla that uses an elevated ground
> screen on 7 towers of its DA array. They have been up for 30 years at
> least. I don't think it has required very much maintenance in that time.
> http://sbe7.org/pics/Elev%20ground%20screen.jpg
>
>
> DHultsman5 at aol.com wrote:
> >
> > In a message dated 2/12/06 3:38:48 P.M. Central Standard Time,
> > barry at oldradio.com writes:
> >
> >
> >>The  elevated ground system is not connected directly to ground but,
> >>instead, is
> >>tied to a buss at the tower end of the radials and  then connected to
> ground
> >>through a tuning circuit (normally a vaccuum  capacitor).  This tuning
> >
> > network
> >
> >>is then adjusted to resonate the  elevated radials against the buried
> ones to
> >>maximize the current at the  tower end of the radials.  I've never
> really dug
> >>into the theory  behind this, but I know that Carl Smith used
> this  technique
> >>successfully in the 60's for an AM antenna system in Alaska
> >>(Barrow?) where the
> >>site restrictions required the installation  of a very short tower
> >>and prevented
> >>the installation of an  adequate traditional ground system.
> >
> >
> >
> >
> > *************************************
> >
> > There is an elevated ground system on a DA in Mobile, AL with one tower
> > similar to the above description.  It is on 660 kHz. @
> 10kW.  with  short towers.
> >
> > As I recall the elevated counter-poise is in four sections and there are
> > four boxes all with a series vacuum capacitor to ground.
> >
> > Dave
> >
> > _______________________________________________


Wow. Get a load of that rusty tower. I wouldn't want to be standing under
that for too long. Certainly wouldn't climb it.





--
JM