Magnetic Ground Saturation

[Anonymous]

Here is an interesting piece of information taken from the Minelab website which relates to the recent posts about magnetic clay.
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When using a detector, strong magnetic fields are transmitted which can "magnetically saturate" the ground adversely affecting the performance of the detector.
Minelab have found, that by applying two different voltages to the transmit coil it cancels signals caused by magnetic saturation.
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OK, Who is going to make a guess as to what this means? Are they using sequential pulses of different single polarity voltages or is this a crafty way to explain bipolar pulse operation? It makes sense to me to use biolar operation as the opposite polarity pulses will stop the magnetic saturation. Anyone with a GP and an oscilloscope could simply hook a small wire loop below the coil to the scope probe to see what is happening, Dave. * * *

 

[Anonymous]

I read a bit further on the Minelab website and I found this:
The GP Extreme combines stable and effective ground balancing with Extreme Depth and Extreme Sensitivity. The Minelab GP extreme is the first detector to use Dual Voltage Technology (DVT).
Minelab have developed Dual Voltage Technology (DVT) based on the Bi-Polar technology used in its military detectors.
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OK, I guess that I answered my own question. Here we have another example of Bruce Candy reinventing the world. Since when was Minelab the first company to use bipolar pulses?
What next? Maybe we will read a press release that Candy invented the steam engine or maybe the Candy Flyer airoplane made him first in flight! Dave. * * *

 

[Anonymous]

Hi Dave,
Bipolar pulses have been used since the 1960's. Barringer Research of Canada used an airborne pulse system for mineral prospecting called INPUT.(Induced PUlse Transient). This used alternate polarity pulses and a multi-channel sampling system.
The weak magnetic fields generated by a PI detector are nowhere near strong enough to cause saturation of ground mineralisation.
Eric.

 

[Anonymous]

Hi Eric/Dave
Even the old J. A. Corbyn design from 1980 you can find on Carl's side is using a Bipolar design.
Mark