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Old August 6th 03, 01:59 PM
Al
 
Posts: n/a
Default Distance to Link Coupling in a Loop Antenna

I have used Reg's fine loop design program rjeloop3 to help me with building
a couple of loops. It was a big help. Thank you Reg.

The shielded three-foot diameter loop I built is for receive only. The
primary loop is six turns paralleled by a variable capacitor, and the
secondary (link loop) is one turn (same diameter) fed to a preamp or
directly to the receiver. The band of operation of the loop is about 200kHz
to 500kHz (NDB chaser).

One question that is not answered in rjeloop3 is what should be the distance
from the output (link) loop to the main loop? The antenna's I built used
flat cable for the wiring and one of the turns was the link so the distance
was 0.050 inches. In other articles I have read that the Q, gain, and S/N
ratio can be varied by varying the distance between the two loops.
Approximately what is the distance? Are we talking a small fraction of an
inch or 2, 3, or perhaps six inches apart? I would just like a feeler
distance to work with. If the distance is to be over one inch, I'm
considering building the primary loop in one hoola-hoop form and the
secondary loop in a second hoola-hoop then varying the distance between the
hoops. Any thoughts on this or is this a waste of time and effort?

All input will be greatly appreciated. Thank you.

Al
KA5JGV