VLF Suggestions for Hot Ground?


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Hi All,

I recently tested several VLF's on some very hot ground in AZ.

Gold Bug. Gold Bug 2, Tesoro Lobo, Garret Scorpion, Whites GMT, MXT, Minelab Eureka and Xterra 70.

The Gold Bugs, Lobo and Scorpion would not GB and were useless.

The Whites were chatty and had really no depth.

The Eureka and Xterra had no problem GB'ing to the test bed of ironstones altho the Xterra would overload on 1 large ironstone.

The test nugget was a solid round flat nugget @ 1/4 gram.

The Eureka Had the best depth @ 3'' followed by the Xterra and GMT at 2" If you didn't know the target was there you would have dismissed it as ground noise with the Whites.

My choice Minelab, unmatched in it's ability to GB and track hot ironstone rich ground.

nvchris

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Hi All,

I recently tested several VLF's on some very hot ground in AZ.

Gold Bug. Gold Bug 2, Tesoro Lobo, Garret Scorpion, Whites GMT, MXT, Minelab Eureka and Xterra 70.

The Gold Bugs, Lobo and Scorpion would not GB and were useless.

The Whites were chatty and had really no depth.

The Eureka and Xterra had no problem GB'ing to the test bed of ironstones altho the Xterra would overload on 1 large ironstone.

The test nugget was a solid round flat nugget @ 1/4 gram.

The Eureka Had the best depth @ 3'' followed by the Xterra and GMT at 2" If you didn't know the target was there you would have dismissed it as ground noise with the Whites.

My choice Minelab, unmatched in it's ability to GB and track hot ironstone rich ground.

nvchris

This is must be a loaded thread!!!! Rob, you didn't have to start this topic to convince me that I done REAL good buying my new Xterra 705 from you! And by the way, how much did you pay nvchris for his post?? LOLOL

Seriously, though, I got the 6” DD coil this afternoon and tried it out in my back yard using 3 nuggets...0.15 gram, 0.5 gram and 7 gram. I've dumped more black sand and small hotrocks back there than can be imagined. I finally found a quiet spot and did auto gb and noise reduction. Using the factory settings after setting gb and noise, I could detect the 0.15 gram nugget at about 1-1.5”. The 0.5 gram nugget sounded off loud and clear at 5” and the 7 gram was detectable at about 9-10”. I then moved each nugget to where the iron mask blanked the sound over a hotrock. There was NO change in the detecting range or signal strength with the nuggets directly over the hot rock.

The only other VLF I've used was a Eureka, which I never got the hang of, but I think the 705 has it beat hands down due to the digital stuff on the 705.

This coming weekend will be the first real test of my 705. I'm heading to Socorro, Jicarilla and Bonita Lake, NM areas for 5 days of prospecting. I figure I'll detect in the mornings and dig dirt and process it in the afternoons/early evenings. Wish me luck!!

Kajun

p.s.

I posted a little review of the 5x10 DD coil late last week. I think the 6” DD has the edge by maybe 0.5-1”.

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Guest Mike C...

I'm with NV Chris on this one there is not a gold only vlf that will handle the hot ground better than the XT18000 and the american goldstriker and still pick up the fly specks---yes I've used a few different vlf's lets see---AU52---V/sat---GM3---Gmt---GB1---3 GB2's---X5---X70--theres probably a few more I used but you get the picture--all the above I have found gold with but hot ground gave them fits where the XT and the AGS handled it better---sorry all you Gmt users :spank:I just tell it how it is ;) -Mike C... :ph34r:

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Hey Guys,

I agree about the Minelab Eureka and this is probably what I will use. Just hoping someone could encourage me to use something beyond a Minelab. I know what the Minelab's can do, and even most of the VLF's, but it's been some time since I used one last. My favorites were the American Gold Striker, XT series, Lobo, Fisher Gold Bug and White's Goldmaster.

Talk with you later,

Rob Allison

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Hey Guys,

I agree about the Minelab Eureka and this is probably what I will use. Just hoping someone could encourage me to use something beyond a Minelab. I know what the Minelab's can do, and even most of the VLF's, but it's been some time since I used one last. My favorites were the American Gold Striker, XT series, Lobo, Fisher Gold Bug and White's Goldmaster.

Talk with you later,

Rob Allison

Part of your question was working around other Minelab PI's. My Dad used a Lobo ST for quite a while (2100 now) and still does occasionally and one thing about it was I could get really close to him, about 10-15 feet (depending on the coil) before I could here him w/ my 4500 (and no special tuning). He would usually hear me first... It is really nice if you are working a small area.

As far as hot ground, I am not sure, we haven't really tested it and I don't think the ground here in So Cal is as hot as AZ ground. But I will say he found alot of nuggets with it in the hottest areas.

I did once work near a Minelab Explorer SE and I had to stay at least 75' feet away, I could actually run closer to a 2100 than the Explorer SE. The guy was swinging it like a golf club and I am sure that made a difference on why I heard him from so far away...

My 2 cents

DigDeep

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I will probably be called crazy but I always liked the fisher Gold Strike I know a few guys who used them with much sucess over the years and all here in AZ. Best part is I think you may know a few of those guys so questions on the unit would be as simple as a phone call.

I also liked the GMT and even the GM4 from whites they too handle the hot rocks pretty good.

have fun going old school LOL

HOTROCK

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G'day nvchris, I'm no expert with vlf's, the only ones I've used are the old Minelab 18000 and the GMT. Out here the high freq setting on the 18000 is just about a passenger, useless in the hot ground, did you try this setting with the eureka?

I'm a little surprised the GMT didn't handle the hot ground better.

Do you remember the settings used?

I bought my wife one last year, her first ever detector.

Where we went detecting, the ground was bad enough to have me using a 14DD and tracking on my GP Extreme (I very rarely use tracking) and even with the DD the ground was still noisy in places, yet when I set up the GMT for my wife, I was surprised how well It handled the ground. Sure it wasn't getting much depth, but she never called me over to reset the thing all day, she just went about collecting a heap shottie pellets and small bits of scrap metal and resetting GB with the thumb pad.

I only used it for about 1/2 an hour, but I was impressed.

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Hi Rob,

Not sure about hot ground. But I can comment on hot rocks. You've been there.

At Moore Creek we have low mineral shale bedrock that makes up the general soil mix. But it is loaded with magnetite basalt cobbles from the uplands, some so magnetic you can pick them up with a magnet. All Minelab SD/GP units prior to the GPX models hit on these rocks with a faint signal.

We have tried lots of VLF units at Moore Creek over the years. What we found is the best units are ones that can be set to tune out an iron object.

Units like the GMT identify iron objects not by nulling out or rejecting them but by identifying them with a different audio signal. In the case of the GMT, gold "beeps" and iron "grunts". The theory, which I believe is correct, is that by rejecting iron signals, some nuggets will also be rejected.

The problem is at a place like Moore Creek, you get iron audio signals with every sweep. The GMT works, but drives you nuts going "grunt, grunt, grunt" for hours on end, while you wait for a "beep". The noise is wearing.

I have great respect for the Minelab XT-18000, American Goldstriker, and Eureka Gold as I have done well with them at other locations. But the Eureka Gold cannot handle the hot rocks at Moore Creek. The only way I could get it to shut up was to go to the 6.4 kHz mode, but the gold sensitivity in that mode sucks. Basically the unit is no good at Moore Creek.

What we found was units that can be set to reject hot rocks have had the most success at Moore Creek. I have found a lot of gold there with the Fisher Gold Bug 2 set in iron disc mode, as the hot rocks are totally rejected or at most just pop or click. The Tesoro Lobo has over time proven itself to be possibly the best performer when put in disc mode and with the disc set at about 1.5 to reject the rocks. The MXT does well in coin mode with just enough disc cranked in to reject the rocks, or in relic mode with key forward, which nulls iron signals.

We've tried oddball units. For some reason the Troy X-5 could not reject the hot rocks unless the disc was cranked very high and/or sensitivity lowered to the point it was no good for gold. The Fisher Impulse, a non-ground balancing PI, hit hot rocks like crazy. The original Gold Bug was useless. The Garrett Stinger was ok. The Fisher Gold Strike was very annoying. Double bleeping all day long.

The X-Terra 70 did well, much better than the Eureka Gold. I'd not hesitate to use it at Moore Creek. A brief spin with a Fisher F75 was very promising, and I will probably give it, and the new White's V3, a go at Moore Creek this summer.

So for Moore Creek at least, so far I'd say Tesoro Lobo, Minelab X-Terra 70/705, White's MXT, or Fisher Gold Bug 2. Of those, the Gold Bug 2 will get the least depth in mineralized ground but is hot on shallow small stuff. So if I had to hunt at Moore Creek a week with a VLF, I'd be hard pressed to decide which of te first three I'd use.

I have to point out questions like this are very site specific. What works well in one place may not work well in another. As has been the case at Moore Creek, you just have to try lots of stuff to see what works best. In general, from what I've seen, I'd go for units in the mid kHz range near 15 kHz and which have some kind of ability to reject an iron hot rock.

Steve Herschbach

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From what I see the difference between the xterra 70 and 705 is as different as night and day, as with the processor being a whole lot faster and when you balance out a hot rock with most machines you will loose depth, but the 705 will average out the hot rock and won't loose depth. A small flake of gold that can't be heard with the 70 will be picked up with the 705. The 705 is a whole different ball game than the 70, using the ellipitical coil

Still playing with it.

Allen

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