[Lowfer] UWL loop

[Stewart Nelson]

Hi all,

IMO, Bill is being too conservative.  It is true that the radiation
resistance of a small loop is proportional to the square of its area,
so for a given antenna current the smaller loop will be 20 dB worse.
However, the Rac of the smaller loop will be only about 1/pi as large,
so for a given Tx power, the smaller loop is only 15 dB worse.

If you made the smaller loop with the same length of the same wire
that was used for the larger loop, you could have three strands in
parallel.  If they were widely spaced, there would be a 5 dB improvement,
resulting in performance 10 dB worse than the larger loop.  Closer
spacing of the strands will, of course, degrade performance somewhat.
My guess is that one inch spacing between strands would result
in a loop about 11 dB worse than the big one.

73,

Stewart KK7KA

> Not to put down the common "how am I coming in" approach, the difference in 
> signal strength at a distant site for a loop with a 15M diameter vs a 15M 
> circumference is basically the ratio of the two areas. This assumes the same 
> conductor type and both loops are at least 6ft above ground at their lowest 
> point. The area for the 15m cir loop is ~180 sq M and the area for the 15M 
> diam loop is ~18 sq M so you are giving up 10X or 20 db.
> 
> The only way to beat this huge deficit (forget the multistrand approach, 
> it's too unstable) is to reduce the loop conductor Rac loss by increasing 
> the diameter of the conductor to the square of the loop diameter ratio. 
> Assuming 0.1" for the larger loop conductor the smaller loop would have a 
> diam of .1 *100 or 10 inches!
> 
> Bill