Maker Pro
Maker Pro

RFID zapper and RFID detector



Jan 1, 1970
Obviously "TwistyCreek" has no clue, and evidently doesn't know what a
grid dip meter is or how it is used.

Harry C.

Why do you say that? You're joking right? OK no tube involved so
there isn't a grid, no "meter" and it won't tune a range of freqs like
a GD meter. He just mentions it works like one.

From the schematic it looks as if he measures the current through a 47
ohm resistor returning the oscillator to ground. If the coil is
brought near another tank tuned to a similar frequency it should
increase the current the oscillator requres and that increase is
detected. That is the general principle of operation of a GD meter.

I haven't tried it, but it certainly looks viable.