1/ Spuriousness and Distorted Responses

In some ways the CTX is highly accurate–other not.

a/ Target Size.

The CTX’s high Gain circuitry acts to make all targets sound bigger.  This sometimes makes it hard to identify objects that are too small to be of value.  The solution is to use the Pinpoint feature to see how responses stand out from the surrounding ground.

Anything that’s really faint should be suspect.  Especially–where you have a loud discriminate response and a faint Pinpoint sound–suspect junk.

As mentioned earlier, reducing the Volume Gain will give a more accurate reporting on these micro conductors.

A second component to this sizing problem is that with the CTX’s algorithmic discrimination  targets may respond in a given category based upon their size.  That is, a low gold “number” will also let in big foil because it mimics the size / conductivity “bracket” that you are after.  Even though the big foil target fits neither category you are trying to isolate–in combination, it passes.

b/ Solidity

This distortion is a result of the amplification that high gain circuitry and a processed signal create.  Targets often sound “fuller” than they are.  I’ve had a lot of experience with this problem running pulses that transmit at 10 uSc and other VLF machines that run at high frequencies.  These machines are made to bring up small stuff and there’s a big learning curve in learning to tell what’s what.  With the CTX, even hairpins and tiny bits of aluminum can initially sound solid.  (See “CTX 3030 ID Tools” below).   It’s tough area of learning with the CTX.  The several gold target studies I’ve looked at show gold (some of it small earrings and chains) coming in though the entire low range.  At the same time, there are a lot of signals in that range that are just not quality responses.   Much of this obvious trash can be recognised if you take the time to examine them.

From: “The Minelab CTX 3030 Gold Hunter’s Guide” by Clive James Clynick (2018)