Hi Alberto
Stokes original article was re-printed in the old LF Experimenters Source
Book, together with another explaining the theory.
I built the original circuit. It is very simple and lacks most of the
features required in a decent receiver.
It definitely works, but I found it did tend to break into oscillation,
possibly because of problems with the screening of the pot leads (although I
am pretty certain I screened them) as he mentions in the revised article. I
also found the 4136 very sensitive to over-voltage and eventually used a
couple of 9V batteries. At 12V problems arise.
I didn't find the tuning that sharp, although I used good polystyrene caps
in the critical places, but that is hardly surprising when you look at the
circuit. As a replacement for a big inductor it's a great idea. My son used
it for a GCSE project for a MSF computer clock and won a prize.
It is perhaps most useful for the "below 9kHz" boys, but only for receive of
course.
I would be interested in your findings.
73 John, G4CNN
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