"Owen Duffy" wrote in message
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"John KD5YI" wrote in
:

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Owen -

I've had this nagging idea for a couple of years: What if the
(single-turn?) loop passes through a toroid which already has, say, 10
or so turns on it? That should give an impedance step-up of 100 or so.
Would that not be a good way to at least get the matching closer? In
fact, the tuning capacitor could be connected to the high impedance
side to reduce the capacitor's value.

Your comments will be appreciated.

I doubt that the transformer you propose would be near as efficient as the
transformer formed by a smaller feed turn. Though it is tempting to
explain
a transformer using turns ratio, the case of the smaller turn is explained
by the ratio of main loop flux intercepted by the feed loop, and that is
determined by area... so deforming the feed loop to change its area will
adjust the transformation.

Owen


Thanks for your reply.

So, as I understand it, there is a large main loop that does the signal
capture. Then there is a smaller loop kind of co-axial with the large loop
and the loops are not electrically connected. Yes? The small loop is a
signal pick-off? Similar to a transformer but with no core?

I seem to recall that a small loop has less inductance than a large loop. I
also seem to recall that the transformation between them is a function of
their inductances. So, a small loop would transform the larger loop's
impedance to an even lower impedance. Is this not so?

John