added 10 nF to my 1500-700Khz ant loop: -- Result: i'm into LW 216khz !
If you search the archives of this group (for example with Google), you
wil find some good info about loops for low frequency reception. One
way to keep the loop's effective self capacitance down is to wind it
with the wires spaces apart some. It is common to use at least one
wire diameter spacing between wires, so it would be at least two times
the wire diameter, center to center. You can also put, say, 11 pieces
of wooden dowel or PVC pipe in a circle. Number them in sequence.
Then wind the wire outside 1, inside 2, outside 3, ... outside 11,
inside 1, outside 2, ... so that each successive turn is on the
opposite side of each particular pipe. (The axis of each pipe is
perpendicular to the plane of the circle.) As you can see, you must
use an odd number of posts in this construction.
There is benefit to making the loop very symmetrical about a vertical
plane, because local sources of noise are likely to be electric field
which is perpendicular to the earth, and will be rejected by such a
symmetrical antenna.
Cheers,
Tom
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