GPX4500 - Enhance V Special modes

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GPX4500 - Enhance V Special modes

Post  bencld on Sun Apr 26, 2009 7:51 pm

Hi all. This may have been answered already but I can be a lazy bugger some times. If it has, point me to the reference will be good.

I had an instance last week where I was working some old diggers heaps. I came back too a heap that I had dug a bit off at about .7 at 5 inches or so. The heap was pipeclay and kaolin with some gravel mixed in. When I dug the piece of gold I was in enhance settings. The second time on this heap I was in special, sens extra, audio quiet and received a reading that I was probably 60 % it was metal. The special, sens extra settings tend to let in a bit more ground noise and hot rocks so I was not 100 % on this reading.

I switched it back to enhance and the reading disappeared completely. I then thought it may be a hot rock. Back to special and it was there. So not sure I took a few inches off and tried again. Stronger response in special but NO response in enhance. Dug another few inches off (around 5 inches out so far) and tried again. Convinced it was metal in special with a strong reading but only a very faint response in enhance. Eventually dug down about 10 inches for a flat piece of fairly rusted steel. Now this seems to me to be a fairly substantial difference in depth between these two settings.

Now what I would like to know is, does the enhance purposely cancel out rusty metal at depth (as a part of reducing hot rocks and ground noise) or is there a big difference in the two settings as this example indicates ? If the processor does do this, will a nugget with a fair amount of ironstone on it be canceled out ?

Any comment/answers appreciated.
Chris.
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Re: GPX4500 - Enhance V Special modes

Post  robby_h on Sun Apr 26, 2009 10:08 pm

Enhance can cancel small and large rusted boot tacks and some other rusted iron objects.

This point should have been raised in a recent discussion regarding Mods to ML pi detectors where it was claimed that the 4500 in Enhance mode "missed" some iron items easily detected by the modified 3000.

They weren't missed. They were ignored! Exclamation

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Re: GPX4500 - Enhance V Special modes

Post  Jonathan Porter on Mon Apr 27, 2009 5:53 am

Enhance will ignore Iron objects (especially heavily rusted/corroded) more readily than non-ferrous, which is what it is doing when it ignores the vast majority of ground noise.

If you are noticing a depth difference between Enhance and any other timings then that would suggest Enhance is not suited to that area as the ground response is not preventing the other more sensitive timings from alerting the operator of a potential target under the coil.

JP
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Re: GPX4500 - Enhance V Special modes

Post  Narrawa on Mon Apr 27, 2009 6:10 pm

1st noticed this with the 4000, showed a gent at our local spot over a very badly rusted nail, that no signal was present at all, yet fired up on the 3000.
The 4500 under the same tests had the same results when comparing the other timings to enhance.
To most it will go unnoticed, but to those who are up to date will find its a blessing, have tested it on .3-.7gram ironstone coated nuggets with no ill effect, & a few larger nuggets that i re berried in heavily ironstone matrix with no problems at all, like Jp says, it depends on the state of decomposing as to whether it will totally ignore it.

"If you are noticing a depth difference between Enhance and any other timings then that would suggest Enhance is not suited to that area as the ground response is not preventing the other more sensitive timings from alerting the operator of a potential target under the coil."

The above quot is a hard thing to try an educate some on after the taste of enhance, like s/smooth on the 4000, use it all the time at your own risk.

PS better still, use it all the time. Laughing
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Re: GPX4500 - Enhance V Special modes

Post  bencld on Mon Apr 27, 2009 6:48 pm

Thanks for the replies blokes. The depth thing is not too much of a problem so long as it is ONLY on rusty metal and not nuggets. This is the thing I am worried about the most !

JP, Narrawa.
"If you are noticing a depth difference between Enhance and any other timings then that would suggest Enhance is not suited to that area as the ground response is not preventing the other more sensitive timings from alerting the operator of a potential target under the coil."

Sorry but I am not quite grasping this one. Could you elaborate a little please ? The place where I noticed and dug these readings was on a pipeclay/kaolin diggers heap which would have to be the most benign quiet bit of ground you could work.

Ta in advance.
Chris.
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Re: GPX4500 - Enhance V Special modes

Post  Narrawa on Mon Apr 27, 2009 11:36 pm

bencld wrote:
"If you are noticing a depth difference between Enhance and any other timings then that would suggest Enhance is not suited to that area as the ground response is not preventing the other more sensitive timings from alerting the operator of a potential target under the coil."

Sorry but I am not quite grasping this one. Could you elaborate a little please ? The place where I noticed and dug these readings was on a pipeclay/kaolin diggers heap which would have to be the most benign quiet bit of ground you could work.

Ta in advance.
Chris.
In this case then id be using s/extra or normal with a mono coil to suit the terrain, then if it proved to be totally benign id try using GB off.
Jp will give you a better example of this, but basically if you can run any of the normal timings over that area without much problems then the use of enhance is not called for over that ground type,,,, or try upping the coil size when using enhance.
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Re: GPX4500 - Enhance V Special modes

Post  Jonathan Porter on Tue Apr 28, 2009 6:37 am

Enhance and Smooth basically tell the detector to ignore or partially ignore the vast majority of ground signal, however it also reduces the response of a lot of targets especially at depth (up to 20% in some cases depending on target size/shape/orientation etc), this means in ground types such as has been described above the detector is not optimised to give the best response to targets based on the amount of mineralisation present. Just as Special/Sensitive Xtra is not perfect for some target sizes and some ground types so is Enhance or Smooth, you the operator have to make that decision based on what you are experiencing in the field.

In some goldfields the ground can just about justify the use of Enhance or Smooth timings all the time (Clermont is a good example of this and explains all the good nugget finds lately) but in other areas this is not the case and a more reserved approach should be used with the timings to leverage the maximum amount of depth allowable once ground type and target size are taken into consideration (Narrawa seems to have cottoned onto this concept cheers ). The problem is Smooth and Enhance can become addictive which means operators can become insulated from the general feedback of the detector when using more aggressive timings, this then means they have to retrain their minds to deal with the feedback of the general responses generated in those timings which can be a little hard (very much like going from a quiet DD coil to a Monoloop).

If in a given ground type you can get better depth on a target in Normal or Sens Xtra timings over Smooth or Enhance then it is recommended to detect in the more aggressive timings assuming you the operator feel you can find the same response free hand (without the knowledge of a target being present). I suggest this because sometimes a target can be better in Normal timings but the ground conditions will still prevent its actual discovery due to the ground being variable or producing similar ground noise type responses, once again it comes down to operator experience making a judgment about what will work best in the given conditions.

Hope this helps,

JP
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