Jim Hemmingway
Hero Member
- Jan 26, 2008
- 791
- 1,624
- Detector(s) used
- F-75, Infinium LS, MXT, GoldBug2, TDI Pro, 1280X Aquanaut, Garrett ProPointer
- Primary Interest:
- Prospecting
Hello Everyone,
With the purchase of some new metal detectors last spring, I put in a test plot just for the heck of it. The soil is a brown clay with maybe an inch max of topsoil overburden. The F-75 ground balance is currently at 84ish and magnetite at 0.1%. The ground balance (GB) with the MXT is at 81ish (I include this for the many folks who own this model).
Under normal dry conditions, on a 10-inch deep nickel (a real nickel composition pre-1981 Canada nickel) the F-75 will easily give a solid two-way signal with a few inches of air space to spare between the coil and the ground surface. Even in the frozen winter conditions of a month ago, it was still pretty much the same good signal, maybe a bit less.
Now the ground where the 10-inch nickel is buried has thawed mostly and is really wet. The wetness probably goes down most of the way. I know this because the garden is adjacent to it, and its always wet down to about a foot at this time of the year.
Checking this 10-inch nickel today, I could just get a not-so-solid two way signal with no room to spare. That’s with the coil swinging back and forth about an inch above the ground. I figure there is about a two-inch loss of depth capability under these wet conditions.
Meanwhile, a 10-inch copper penny buried further up the yard at a higher elevation, under the trees where the ground is much drier but still damper than usual….is giving a slightly improved signal.
As an aside, I’ve always figured all my detectors achieved better depths over our fresh water sand beaches that were always wet at any depth.
A friend from down south sent me a copy of his soil analysis, performed by a leading metal detector manufacturer. It’s interesting because although it’s tougher ground than mine (iron oxides...type not stated in report), when dry it can be ground balanced and decent depths can be had. However, when wet, ground balance is not nearly as effective, and the ground is hard for a signal to penetrate. In fact, the analysis engineer states that there is a world of difference between that soil when dry as compared to when it’s wet. It would seem that somehow the wet conditions “activate” the iron oxides in the soil similar to the way wet conditions affect salt areas….so states the report. Interesting stuff don’t you think?
Does anyone else monitor their test plot signal responses over varying moisture conditions?
Have you noticed differences in depth results? Patterns over time?
Jim.
With the purchase of some new metal detectors last spring, I put in a test plot just for the heck of it. The soil is a brown clay with maybe an inch max of topsoil overburden. The F-75 ground balance is currently at 84ish and magnetite at 0.1%. The ground balance (GB) with the MXT is at 81ish (I include this for the many folks who own this model).
Under normal dry conditions, on a 10-inch deep nickel (a real nickel composition pre-1981 Canada nickel) the F-75 will easily give a solid two-way signal with a few inches of air space to spare between the coil and the ground surface. Even in the frozen winter conditions of a month ago, it was still pretty much the same good signal, maybe a bit less.
Now the ground where the 10-inch nickel is buried has thawed mostly and is really wet. The wetness probably goes down most of the way. I know this because the garden is adjacent to it, and its always wet down to about a foot at this time of the year.
Checking this 10-inch nickel today, I could just get a not-so-solid two way signal with no room to spare. That’s with the coil swinging back and forth about an inch above the ground. I figure there is about a two-inch loss of depth capability under these wet conditions.
Meanwhile, a 10-inch copper penny buried further up the yard at a higher elevation, under the trees where the ground is much drier but still damper than usual….is giving a slightly improved signal.
As an aside, I’ve always figured all my detectors achieved better depths over our fresh water sand beaches that were always wet at any depth.
A friend from down south sent me a copy of his soil analysis, performed by a leading metal detector manufacturer. It’s interesting because although it’s tougher ground than mine (iron oxides...type not stated in report), when dry it can be ground balanced and decent depths can be had. However, when wet, ground balance is not nearly as effective, and the ground is hard for a signal to penetrate. In fact, the analysis engineer states that there is a world of difference between that soil when dry as compared to when it’s wet. It would seem that somehow the wet conditions “activate” the iron oxides in the soil similar to the way wet conditions affect salt areas….so states the report. Interesting stuff don’t you think?
Does anyone else monitor their test plot signal responses over varying moisture conditions?
Have you noticed differences in depth results? Patterns over time?
Jim.
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