More MD ????

"The depth range of GPR is limited by the electrical conductivity of the ground, the transmitted center frequency and the radiated power. As conductivity increases, the penetration depth also decreases. This is because the electromagnetic energy is more quickly dissipated into heat, causing a loss in signal strength at depth. Higher frequencies do not penetrate as far as lower frequencies, but give better resolution. Optimal depth penetration is achieved in ice where the depth of penetration can achieve several hundred meters. Good penetration is also achieved in dry sandy soils or massive dry materials such as granite, limestone, and concrete where the depth of penetration could be up to 15 m. In moist and/or clay-laden soils and soils with high electrical conductivity, penetration is sometimes only a few centimetres."

[en.wikipedia.org]

How do these observations/statements translate for metal detecting?

A. "As conductivity increases, the penetration depth also decreases. This is because the electromagnetic energy is more quickly dissipated into heat, causing a loss in signal strength at depth. In moist and/or clay-laden soils and soils with high electrical conductivity, penetration is sometimes only a few centimetres"

I always thought moist soil gave better depth and conductivity for metal detecting. True or False?

B. "Higher frequencies do not penetrate as far as lower frequencies, but give better resolution."

High versus low freq and depth and type of metal?


C. "Optimal depth penetration is achieved in ice where the depth of penetration can achieve several hundred meters."

Does this apply to frozen ground? I noticed some exceptional depth this winter in cold and frozen ground. 18" eagle button through snow and 20 " gold civil war soldiers ring in cold wet soil.



Also any ideas what kind of detector and coil this soldier is using in Iraq?

[en.wikipedia.org]

Answered one of my ?.

A U.S. Army soldier using a Schiebel AN 19/2 MOD7 metal detector, public domain photo from navy.mil

[en.wikipedia.org]

[www.eudem.vub.ac.be]



Edited 1 time(s). Last edit at 04/28/2010 01:03AM by jamt225.

There is a fair amount of similarity; yet, some differences.

A. True. Although with a metal detector.....the higher the conductivity of the ground (higher mineralization)......the more of the EM energy from the detector is 'attenuated'......(vs heat generated).
Moist soil can help detection range.....AS LONG AS.....the ground has minimal mineralization.

B. True. And in our case with a metal detector..........the higher the operating freq..the better the detection of low conductive metals. High freq for finding low conductive gold...........................and low operating freq for finding highly conductive silver. (Copper is '100' and silver is '106'; subsequently making copper as the base reference for which to compare metal conductivity).

C. Minutely' applies to inductive-balance metal detectors.