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Gold Field Program Not As Sensitive As Discrimination Mode?


57buick

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So, I was prospecting some bedrock along the river today with the 9" round HF coil. I was trying to use the gold field program but man it was noisy on those black sand rocks constantly. I switched to some other programs like HOT for awhile and got a good hit. Dug out the crack and found a lead fishing buckshot. 

Figured it was a perfect opportunity to test some programs. I reburied it about 3 inches deep. Strangely what I found was on the Gold Field program I could not tell any difference in sound from the host rock. I Never would have dug it. Switched to a modified HOT program I have saved and it rang nice and loud with no sound from the rocks.  What am I missing? Will the elliptical be any better when it gets here? have one on order still.

Is there some tweaking I need to do on the Gold Field? Like notching out the rocks? I forgot to try that while I was out there, started raining on us

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I have no suggestion other than I have forgot to re-GB after switching frequencies and caused myself problems.

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55 minutes ago, goldbrick said:

I have no suggestion other than I have forgot to re-GB after switching frequencies and caused myself problems.

now that you mention it maybe because I was quickly switching around and forgot to do that too. that might have made a difference

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  • 3 weeks later...

Are you saying the bedrock itself is actually sounding off, and you can’t tell the nugget sound from the bedrock sound? In theory you should be ground balancing the bedrock out so it makes no sound at all before proceeding. Or is it that you simply can’t get a signal in the Gold Field program when the bedrock itself has been ground balanced out?

The Gold Field program does have a softer more rounded off response to anything, I Found it easier to get targets to “pop” using the other programs. Gold Field is an all metal mode and sort of like listening to a live feed. The discrimination programs decide what is good and bad. Bad signals are silenced, but good signals are enhanced. In an all metal mode it can be hard to work some areas because uneven mineralization can produce soft responses that compete with the nugget sounds. Going to a discrimination mode can silence those spurious mineralization sounds and make it easier to operate.

Other detectors like the Gold Bug 2 are similar. The all metal mode produces soft responses on small targets, a soft zip zip. Go to disc mode and that soft zip becomes a sharp beep.

It just so happens that I am out testing the Gold Monster, Gold Racer, and Gold Bug 2 on some of the most magnetite laden serpentine ground I can get to. I swear the soil in places is half magnetite - drop a magnet into it and more sticks to the magnet than stays on the ground. My VLF skills are rusty from too much PI detecting and even the GPZ is more forgiving than a hot VLF in bad ground.

I will post in more detail about all this later on the main forum but it has been educational comparing the detectors on a target in both all metal and disc modes. The first step is to run the detector around and do whatever it takes to get the ground to shut up. This means running the sensitivity in particular far lower than normal. You can’t find gold if the ground is constantly signaling. The Gold Monster for instance can run as high as sensitivity 10 but on this ground I can get smooth operation in all metal at 3 or maybe 4 at most. Now, you would think detecting like that would be a waste of time, but the Monster hits gold at sensitivity 3 that the Gold Bug 2 can’t hit at all no matter how I set it. Ultra high frequencies have very poor penetration in bad ground.

Anyway, in tough ground spot on ground balance and lower sensitivity are keys. For machines that offer an adjustable threshold retune function (SAT, iSAT, mineralization modes on Gold Bug 2) getting the threshold reset speed just right (usually needs faster than normal settings in bad ground). If you have a detector that can frequency shift, more moderate frequencies can help. The Deus elliptical at 74 kHz May very well be too hot and suffer for it in bad ground, just like the Gold Bug 2 does. The difference with a Deus is you can just shift it down to a lower frequency that handles the bad ground and hot rocks better.

VLF detecting in bad ground is no easy chore for those not used to it. Spending a couple hours at least doing test stuff like I am doing with these three detectors can be very, very educational.

 

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