Bill A wrote:

> ......so for tranmitting it would seem to be a good idea to have a

bottom

wire on, or in the ground.
The problem is that the soil losses become fairly large. Think of the loop
wire with a huge donut-like AC magnetic field surrounding it. This field
doesn't seem to like the composition of the ground, which in effect, adds
series resistance to the loop circuit. I find the best compromise in
reduction of soil loss Vs maximizing the loop area by keeping the lower
conductor at least 5ft above ground. This distance could vary depending on
the soil type. The soil here in the Boston area, is composed of at least

60%

sand, covered by a thin layer of top soil.
>This would have the added advantage of making it possible to use a very
thick or multiple thick >wires for this part of the loop thus reducing the
total loss resistance by almost 50%, with a
>consequent considerable increase in efficiency.

For the bottom wire of my 73kHz loop, I used 3-core mains flex at 5ft above
ground. My wife used it as a washing line!

Mike, G3XDV
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