GPX 17 Coil Commentary

[Jonathan Porter]

Interesting results with the DD coil Steve, that ground must be pretty bad as I would not have considered the way the DD is configured on the GPX6000 to be that much different than the mono coils in bad ground. Did you by chance do a comparison between EMI and Salt mode? In my experience I’ve found salt to have better performance over variable ground compared to Cancel mode. Edit: In Difficult mode.

JP

[Steve Herschbach]

There was no discernible difference between salt and cancel in this ground. I’m sure that would change entirely on a saltwater beach. We tested four locations, from bad to worse to horrible. But I must emphasize I test rather casually, only looking for the clues I need to suit me and my purposes, so people should not treat this stuff as gospel, just a rough guide at best. Your own ground rules, not mine. 

It is impossible for me to overemphasize how bad this location is. You may as well try detecting in iron filings. Just a FYI a GPX 6000 with an 11” mono easily bests a Fisher Impulse AQ with 12” mono, and the larger GPX coils blow the Impulse away. In case people are wondering, I’m toying around with the 6K as a beach detecting option, but the info gained will help me on serpentine ground chasing nuggets. Anyone hunting dry washes loaded with visible magnetite will also want to take note.

What you see on a magnet…

[dig4gold]

Steve said.  Your own ground rules, not mine. 

Ain't that the truth. Our grounds are not all equal. So you need to work out what works for you & your conditions. You can't go entirely off others settings & coil selections. They can be a guide but not hard & fast.

 

Greg 🙂 

[Jonathan Porter]

Wow that is some serious black sand!!😳 I presume you guys have goldfields areas that are similar? I remember some gullies in Arizona having huge amounts of it in the bottoms of the creeks and behind obstacles!! 

Getting back to the Salt and Cancel modes I’ve not done a lot of work using Normal timings so my observations were mainly in variable hot ground that required the use of Difficult. 

In the case of the 17” I’ve found the biggest disadvantage is in the increase in salt or conductive signals due to the bigger size, there were some places where I could use the GPX11 with a bit of movement signal but when I tried the GPX17 it was virtually unusable. The next issue of course will be the obvious one which will be more EMI , for us this will start to appear next month as our weather starts to change.

Mineralisation with the 17 seemed if anything slightly less from a variability from surface concentrations POV but there was some deeper sounding hot areas that sounded better with the bigger coil as expected. The true eye opener is the outright sensitivity for such a large coil, there is not much of a drop off on tiny target sensitivity when you go to the larger coil except for the usual bigger coil into tighter spaces loss as is to be expected. This point really makes the GPX17 a game changer as you can cover vast tracts of country very quickly and snag the tiniest of pieces that could point you to a potential patch of missed gold. 😎 

JP

Recent starter nugget in virgin ground that lead to well over an ounce in a few days.

A few nice chunkster payday nuggets came out when working the area

First days haul

Gold I found working the patch over a number of days, all thanks to that first tiny piece I found wandering around with the GPX17 😊 

[dig4gold]

Nice finds Jonathan. What sort of depth were they at? Cheers.

 

Greg 

[Marty]

This would have to be the best informative post about the 6000 yet 
Thanks to Steve and JP for giving us all a better understanding just what the 6000 can and cant do and what coil does what.
Great Post Steve 👍

[phrunt]

strick has done his excellent X-rays inside the GPX 6000 coils now, he's put them into his awesome "What's in your coil" thread.

You can see the dreaded chip in the coils too 🙂

[Steve Herschbach]

Interesting on the DD how nearly all the windings are on the left hand side, only a couple turns on the left. I've never seen a DD coil like that, not that I've seen a lot. But the ones I've seen were would similarly on both sides.

[Chet]

3 hours ago, Steve Herschbach said:

Interesting on the DD how nearly all the windings are on the left hand side, only a couple turns on the left. I've never seen a DD coil like that, not that I've seen a lot. But the ones I've seen were would similarly on both sides.

Steve

I edited some notes into the x-rays that may clarify this somewhat.

Have a good day,

Chet

[phrunt]

Yup, this is what was called partially spiral wound, instead of being laid out completely flat like a fully spiral there is a layer of flat windings over another layer of flat windings.