[BC] Carl Smith method of dual ground system

[Alan Alsobrook]

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
> 
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-- 
Alan Alsobrook CSRE AMD CBNT
St. Augustine Fl. 32086 904-829-8885
aalso at Bellsouth.net