Re: Mini coil earth?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Mddeming-at-aol-dot-com 

In a message dated 10/5/03 11:50:05 AM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:
Street signs work great for a counterpoise. They lay flat and are rugged. I
use either a flat square plate (Do Not Enter) or a flat circle plate (RxR)
mainly for certain measurements. These signs are 30" across and perfect for
the task. Prior to these "finds", I simply used Al-foil laid down under
the coil which worked just fine. The street signs, however, are the perfect
counterpoise for many coils (plop it down and setup the coil).

Bart

     Solid plate counterpoises are very convenient. The problem with them 
is that of eddy current losses which can be reduced somewhat by using wire 
mesh instead of a solid, and minimized by using a wire array laid out like 
daisy petals beneath the coil. The latter design takes longer to set up, so 
one has to balance convenience vs losses based on the particular needs.

Matt D.