[160m] KC2TX magnetic loop

[Tom Rauch]

For anyone interested the URL is:

http://www.qsl.net/kc2tx/loopschematic.htm

My comments are it looks like a good basic design. He has the split in the
shield at the very top, not at the bottom. Everything is grounded only at
the bottom. Many loop designs miss the very important point the loop should
be open exactly at the top, exactly opposite the feed, and all rounding
should be at the bottom and be symmetrical in distance both ways around the
loop to the open point.

That's because the shield is the actual antenna that "picks up the signal",
and it must be balanced.

The only thing I would question is directly paralleling the two loops, and
the lack of impedance matching. The only effect of this would be to reduce
loop sensitivity. That could be made up with an amplifier, but in general
you are better off to extract the most signal possible.

It is often OK to directly parallel hi-Q series resonant circuits, but it
does not work with parallel resonant systems. These loops are parallel
resonant, so each has a low impedance off-resonance.

50 feet may be close, but you can probably turn the loop to obtain minimum
noise.

73, Tom W8JI

> Also, I am concerned about the distance between the transmit L and the
> receiving loop.  I can probably only get about 50 feet or so spacing
between
> the two antennas.  Is this going to be a problem?  I live on a small 1/4
> acre lot and don't have much room.