Please Answer???

[J_Player]

Originally Posted by WM6

For coin it cannot be used for sure.

For other target sensitivity depend on "virginity" of terrain: in soil hard polluted with civilisation trash there will be too much disturbing signals to differentiate it from useful signals. On clear terrain you can detect one 50x50cm metallic plate at some meter distance (it depend on detecting angle too).

Of course sensitivity (in fact directivity) depend on how large ferrite rod is (you can glue two ferrite rod together to enlarge it).

You need first to tune your Earth signal detector to strongest and steady signal (Earth signals are not the same during time of day).

Hi WM6,
This could be used as a nice metal detector for large objects.
But I was wondering if you can post a circuit with tuning instructions for a long range detector that gives a flat response over the treasure metal band?
I am mostly interested in the gold/silver band, but I also would like to detect the platinum alloys which might be found when people lose their jewelry at the beach.

A simple analogue circuit with ferrite would be good, but I prefer a hybrid with a 256 channel detector plus 4 application Specific Integrated Circuits (ASICs), comprising 64 channels each, which perform front end analogue signal processing, A/D conversion and multiplexing.
of course, the unit must be portable to carry into the field.
And it must be able to contend with the rigors of hiking over hill and dale, and must be rugged enough to withstand occasional dropping in the mud during the treasure hunting operations.
However, if the platform is spin-stabilised, the earth image could be stabilised on the detector using a de-spin mirror.
Then the earth image would be present on the detector only for 40 ms at the most, and the S/N could be kept to acceptable levels for jewelry recovery purposes.

Maybe this is too much to ask, but I would like if you can post a project that can do this if it is possible.


Best wishes,
J_P