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ddmk6
07-01-2011, 06:42 AM
Hi folks,

I have been playing around with settings on the GPX 5000. I have an area that I'm trying to get the maximum depth out of (isn't that always the case:)). Up to this point I have been running in the fine gold timing with the gain bumped up to 19 using the 12 x 18" Goldstalker mono. I have read that the fine gold timing may not be the best to use for deep nuggets. Anyone have any idea on this one?

I tried playing around with the deep setting yesterday. It seemed a bit unstable with the 18" coil, and that's with a lower gain setting. I think the preset was around 14 if I remember right.

I know the machine will reach down there, a tin can at 3 feet doesn't stand a chance....If any of you have suggestions to optimize for deep nuggets, I'm all ears.

Thanks in advance....I'm off to the hills.

Kenny

Steve Herschbach
07-01-2011, 02:56 PM
Hi Kenny,

Depends on what size the gold is and the ground mineralization. Most ground in Alaska is relatively mild. The Fine setting is for small gold in very mineralized ground. I am by no means a GPX tuning expert but in Alaska I usually just in Normal with the Gain bumped up as high as I can go and still have a stable threshold. In very mild ground the Sharp setting can give you a distinct advantage. See the chart at http://www.akmining.com/mine/minelab_gpx_5000.htm for a guide to which setting to use when.

Reno Chris
07-01-2011, 07:01 PM
In California this last week, in ground mild enough to easily use a Gold Bug 2, I was running sharp, and got a 2.1 gram piece at a good 8 to 9 inches. The target was very noticeable and not weak at all. If the ground is mild enough, Sharp or sensitive extra (when going for small gold) are the settings to go for.

Chris

ddmk6
07-01-2011, 09:00 PM
Hi Guys,

Thanks for the help. The gold in this particular spot is pretty good size. The smallest I have found so far is right at 1 gram and they go up from there. There have been some big chunks found on this mountain.

I tried the sharp mode the other day. I think the ground may be a little too hot for this mode. I did not try turning down the gain though. I will play around with sharp and normal tomorrow and see what kind of difference it makes. I need to find a cut bank somewhere and take the time to play around with different settings. It's hard to stop and take the time when your finding good gold though.

Thanks again for your input.

Kenny

ddmk6
07-02-2011, 08:18 PM
Hello again......I played around with the settings a bit today. Unfortunately no large deep nuggets to report or test the machine on. Found some smaller surface nuggets, but nothing to test my setting choices. Sweep speed, Ground Balance, and stabilizer settings remained the same for all timings.

I tried the sharp timing with gain at 19, sweep speed slow, stabilizer 12, GB fixed. The machine would run pretty stable until I hit a hot patch of ground. Then it would not keep up without reducing gain quite a bit.

In the normal timing the machine handled the ground a little better, but to keep it stable in all ground conditions the gain had to be reduced to 11.

The fine Gold timing performed very well in all ground conditions with the gain cranked up to 19. There was a small bit of instability in the hot patches.

My question is this....When looking for large nuggets (oz plus) in relatively hot ground. Would it be better to run the fine gold timings with the gain cranked up to 19, or in normal timing with the gain reduced to 11?

I know this machine is new to all of us, so there is still a bunch of testing to be done. Just something to think about.

Thanks,

Kenny

Reno Chris
07-02-2011, 10:46 PM
1. Fine gold is not a setting optimized for deep, large nuggets. That's why they call it fine gold. Read the manual comments on all the settings.
2. turning up the gain to max or very near max is a beginners mistake - its more likely to give you ground noise and interference problems than a significant depth increase. Its not like a radio - set on 1 you can hardly hear it, set it on 20 it blows your ears out. On the GPX5000, set on one is still a lot of gain - only slightly less than normal. Set on 12 is what they used on the older GPs, set on 20 is only a little higher gain than normal. Bumping up gain wont give you a great big depth increase. Timings are more important than gain.
3. Which setting will work best in your conditions? Only you can determine that by testing, so no point in asking us - I have no idea what in your mind constitutes "relatively" hot ground. I would guess the better setting would be sharp with reduced gain, but no way to know without testing.
4. The stabilizer setting is counter intuitive. A setting of 2 provides much more stability than a setting of 12. One would normally think turn up the stabilizer setting to increase stability, but that's not so. Read the manual.
5. Give the deep audio setting a try and test it out.
6. Bottom line: Want to go deep for big nuggets? Get a bigger coil! 12 x 18 would get roughly the same depth as a 14 inch round - a medium sized coil. I use a 20 inch round to go deep - I once used it to find a 1/2 ouncer I missed with my 11x17 coiltek oval, even though I pounded that spot with the smaller coils. If it seems costly, one half ounce or larger nugget will more than pay for the big coil.

ddmk6
07-03-2011, 08:08 PM
Well, I broke down today and took some time to make a test area when I found a mound of "relatively hot" dirt. I made my own cut bank with holes approx 6", 14" and 30". I stuck a 3/4 oz piece in the 6" slot, easily heard on all timings with the 18" goldstalker.

Moved it down to the 14" slot. Surprisingly still easily heard on all timings. I ran through all of them except salt and coin/relic of course. No timing seemed to stand out more than the others. The only difference was an inverted tone on some of the timings and not on some of the others. The sharp timing had a warbly tone at this depth but was still easily heard. Kind of surprised that they were all pretty much the same.

Moved it down to the 30" slot. Could not pick it up with any of the timings.

Conclusion, I kept the machine in the fine gold timing, because at least with that I could hear my sub gram piece while still hearing the deeper larger pieces. Some of the other timings had a hard time picking up the sub gram piece. For instance the sharp timing would barely pick up the sub gram piece when scrubbing the coil right on it while the fine gold timing would pick it up when nearly 3" above it (in air).

I didn't spend a huge amount of time doing this. I kept the stabilizer set at 12 on all timings and ran the gain up as high as possible while still maintaining a smooth threshold. Sweep speed was set at slow. All of the other settings were factory. When I get some more time I will play around with some of the other settings and see one timing will stand out above the rest. So far though it doesn't seem to care what the timings are, just put it over gold and it will do it's job :-).

Kenny