11
Pulse Delay
affects the ground balance point, so whenever
the delay is changed the ground balance should also be checked
and re-adjusted. Higher pulse delays require a lower ground
balance setting.
Target Conductivity
Target Conductivity
refers to the reactance of the target either
above or below the ground balance point of the TDI. General-
ly-speaking, gold is considered to be a low conductor (high tone)
and silver a high conductor (low tone). Iron often produces a
confused, warbly pitch that jumps back and forth between high
and low tones. The two-tone response is disabled when ground
balance knob is turned to the
OFF
position.
Be aware that target conductivities can vary considerably,
even targets of the same metal. Small gold nuggets are usually
low and large gold nuggets are usually high, but where the tran-
sition occurs depends on the composition of the gold alloy. Be
mindful that searching in low-conductivity mode could eliminate
very large nuggets, if any happen to be in the area
1
.
The same is true for relics and jewelry. Many bullets, but-
tons, and most buckles register as high conductors, but cuff
buttons often respond as low conductors. Most small jewelry
responds as low conductors, but larger men’s rings can easily fall
in the high-conductive range. Most coins fall in the high range,
except for e.g. US nickels and small or thin coins like hammered
silvers or very small bronze coins.
1. The potential for Very Large Nuggets depends on where you are
detecting. In most gold-bearing regions of the US, detectable
gold is found as small placer nuggets up to multiple grams in size
which register as low conductive targets. Alaskan and Australian
gold is still being found in multiple ounce-sized nuggets, which
may respond as a high conductive target.
