david,
you said in a previous post that:
"I hunt an area with this devil dirt and what I have learned is that you can pretty much forget the tones.Anything beyond three inches is going to sound like iron until you uncover the target.If you hunt this ground with an Etrac waiting for a high tone squeal,you will miss more than you will find."
Yes I have run into something similar to this.and you are right about forgetting about the tones.
In helping to determine a detectors capability, I made up a test capsule, using an old CD case full of a naturally occurring red pea gravel. Where it did not occur naturally, some old building sites had this stuff put on them as a road base. This example is 1cm approx. round gravel is made up of basically, an iron oxide that is so concentrated , that the ones I have gathered, each pebble is attracted to a magnet. Under these pebbles in the test capsule, I usually place a copper or silver coin or gold rings/s. It replicates/simulates some of the more extreme soil conditions here in my part of the world, near Perth, Western Australia.This stuff does NOT affect the null either. On the Etrac, the THRESHOLD remains steady.
There's all these tiny rusted "shards" mixed in some of the soil at some relic sites that's made up of old manufactured (man made) whole iron.I'm sure there are sites like that over there in your part of the world as well that are probably similar.
It really interferes with a detectors ability to see a non ferrous object buried in or under it and were not just talking about individual iron nails as the culprits. Differnce is that this type of soil with whole iron DOES cause the THRESHOLD to NULL.
Also tried many different coils and settings to try and see if I could detect a non-ferrous target, of variable size and metals under this test capsule and found that only the PINPOINT was able to detect the actual target.
Kind regards
david di
