loop antenna questions
 

i am constructing the typical bcb receiving loop. its 18 inches on a
side, 15 to 18 turns, 365 variable cap, the usual setup. my question is
this, is it feasible to throw one or two turns on the same frame
parallel to the other turns to tune a sw loop? does the proximity of the
other bcb loop wreck the characteristics of the sw loop? how about if i
switch the variable from one loop to the other, leaving the opposite
loop open and untuned? or how about switching in taps, decreasing the
number of turns at each interval to tune from bcb up to sw? would the
unused turns on the frame make the remaining loop untuneable?

In article ,
(Jim) wrote:

i am constructing the typical bcb receiving loop. its 18 inches on a
side, 15 to 18 turns, 365 variable cap, the usual setup. my question is
this, is it feasible to throw one or two turns on the same frame
parallel to the other turns to tune a sw loop? does the proximity of the
other bcb loop wreck the characteristics of the sw loop? how about if i
switch the variable from one loop to the other, leaving the opposite
loop open and untuned? or how about switching in taps, decreasing the
number of turns at each interval to tune from bcb up to sw? would the
unused turns on the frame make the remaining loop untuneable?

If I understand you what you want to do is make two loops, one for MW
and the other for SW with fewer turns for two resonate loops.

You could just leave the terminals open on the unused loop where it
would not affect the in use loop much.

--
Telamon
Ventura, California

JIM,

i like the idea of the smaller loop inside the larger one. the frame is
for an edge winding like a box loop. i could do a spiral winding for the
sw loop inside, then the nulls would be at 90 degree angles to help
avoid interaction. my purpose is to have both sw and bcb available on
the same antenna lead because my radio uses the same ant input jack for
both sw and bcb antennas. i want one portable package that eliminates
the need to change plugs to go from sw to bcb. i can mount a switch to
drop the variable across the winding i need and save wear and tear on my
plugs. thanks for your thoughts!

JIM,

One more thing to consider the difference in the "Spacing"
of the Turns for the Two 'separated' Loops :