Osprey expressed precisely :
JellyBelly wrote:
wrote in message


theyre esy to make if you can do basic electronics.


NT

Er... I think he probably knows that but was, perhaps, looking for
instructions or some sort of help with making one )



I would be happy to make one if someone has such a circuit.
Assume I would need a High Frequency transmitter, 300Khz they seem to
work at .. and a separate induction pick up, which could possibly be a
tuned aerial, a circuit to convert this signal to an audible one, and
amp to drive a speaker.
Now if someone happens to have such a circuit - I'd give it a go ....
veroboard & components no problem, but don't want to get into PCB
drafting & etching.

Look up a 555 timer IC oscillator circuit. From memory they will easily
run up to 300Khz, then just connect your cable to the 555's output.
Trace it with a small radio tuned to 300khz.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk