Fisher F75SE vs Minelab CTX 3030 vs Nokta FORS Gold vs White's V3i

[Steve Herschbach]

This should be interesting.

The reality these days is that when it comes to nugget detecting I am very much a pulse induction kind of guy. I also go out of my way to point out the problems with using VLF detectors and discrimination while nugget detecting.

Yet at the same time I have very much been a proponent of using VLF detectors and discrimination where it may offer some sort of advantage. Ganes Creek, Alaska was the best example of a location with large nuggets and tons of ferrous junk to contend with. A good discriminating VLF detector made sense there and the vast majority of the gold found at Ganes Creek was found with VLF detectors.

I am seeing similar situations here down south, especially in California. Places where 150 years of mining has left ferrous trash galore. What I am looking for is a way to narrow things down a bit in some situations. The idea in some places with unknown potential is to scout first with the VLF, and then, if any gold is found, to switch to a PI and hammer the spot.

There are the big cobble piles, that may have a big cobble shot full of gold, but which are more likely to contain a rusted can. A big coil on a VLF could be handy for scouting those.

Finally, I want to do some honest blue sky prospecting where I put myself in gold country but not specifically on a proven location and go looking for a patch. A lot of this would be in logging country and steel wire and other ferrous trash can be common. I can deal with the bullets but may want to weed out the ferrous.

I ended up by chance with a Nokta FORS Gold that came with a 13.5" x 15.5" DD coil. This machine has a great two tone mode where all targets signal, but ferrous with a low tone, and non-ferrous with a high tone. My preferred mode for scouting trashy terrain. I hear all targets so nothing gets passed without thought. I may investigate some ferrous signals further if I am suspicious.

I have a new Fisher F75SE coming, a model without the latest updates. I may end up also with an updated version but got tired of waiting on that so bought this one to use for now. It also gives me a baseline to compare to should I ever lay hands on a newer unit. Or one I can upgrade later if I wish. To compare apples and apples I have a new DeTech 12" x 15" DD coil on the way for the F75 to use versus the Nokta with similar coil.

I have a friend who did very well at Ganes Creek in the 22.5 kHz dedicated frequency prospecting mode, and his main claim was that it had killer discrimination. So just to make life interesting I have another DeTech 12" x 15" DD coil on the way to use on the V3i versus the other two detectors.

Finally, I will toss my CTX 3030 with 13" x 17" coil in on this little competition though it is a slightly different coil. Close enough though and should be interesting. There is already a huge thread going on the CTX and gold at http://www.detectorprospector.com/forum/topic/361-minelab-ctx-3030-for-gold-nuggets/

I honestly look at this as more a shootout between the F75 and the Nokta more because I see them more as get down and play in the mud prospecting detectors. The CTX and V3i are more my in town units. But maybe that is just a perception thing on my part and since I own both anyway - why not? Looked at another way these do represent some company flagship units, say what else you may about them. Maybe there will be surprises and no matter what, I have a lot to learn here. And that, my friends, I do enjoy!

OK, now the bad news. I am not much for contrived testing so I will need favorable weather to get these detectors out of town into real field conditions to give this all a try. And I do not want to rush to judgement in any case. Eventually it will all sort out and I will report along the way if anything of interest develops. Until then, you will have to be patient.

Again, lest anyone think I am believing this all to be some kind of magic gold getting idea, it is not at all. I will be using a PI detector for most of my nugget detecting in 2015 and basically digging everything I come across. This is actually part of my weeding down detectors process with the main goal being to let either the F75 or FORS Gold go away. I have other reasons for keeping the CTX and V3i so they are just going along for the ride and the potential for extra knowledge. When I go out this summer I want to be packing both a PI and a VLF. The intent is to use the PI and have the VLF more for backup or for getting into a real trashy location. This shootout will determine just what VLF gets to go with me this summer.

The photo below shows all four coils side by side with weights as weighed on my postal scale with scuff covers. The dimensions are width by length at longest point with the third dimension being the length of the actual middle DD overlap working area. The two DeTech coils are 12.75" in this regard versus 14.25" for the Nokta and 15.5" for the CTX 3030. This would be the nominal length to shoot for on each coil sweep if you figure no overlap (which would not be wise). The Nokta is the lightest coil so in theory combining weight with area covered it has the best overall specs as regards area covered for weight handled. The angle of the picture and coil placing tends to make the Nokta coil look smaller than the DeTech coils but it is in fact slightly larger.

Last funny note. I would normally complain about putting coils this size on VLF detectors because in the past it made them nose heavy and had me whining about the weight. However, world class lead weight PI detectors have made it so I have gotten used to using machines far heavier than these beasts, even with their larger coils. Go figure.

[gambler]

subscribed to the future awesomeness. can you start tomorrow?    

[Steve Herschbach]

I am not a huge fan of air tests as relating to real world performance but they can be instructive. They may not reveal what a detector can do in the ground per se, but they can eliminate certain possibilities. If an item cannot be detected in an air test, the chances of hitting it in the ground are nil.

I set up the Fisher F75 SE with the 5" round DD coil. The Minelab CTX 3030 with the 6" round DD coil. The Nokta FORS Gold with the 4.7" x 5.2" DD coil. And the White's V3i with the 4" x 6" DD coil. Close as I could get them all to each other.

I then subjected them to my Bic Ballpoint Test. For many years in a retail environment I have found the perfect small test item to be a cheap Bic pen with an all plastic barrel, and brass tip with 1mm tungsten carbide ball. A "med/moy" or "medium" point. The plastic barrel serves to keep your hand from affecting hot machines like a Gold Bug 2 or GMT. Papermate has an equivalent all plastic pen with a small brass tip.

In a nutshell, if a detector can't hit the ballpoint, it is not going to do well as a small nugget detector. Most coin detectors you can sign your name on the coil and get no signal. Nearly all VLF detectors sold expressly for nugget detecting pass this simple test.

Why not use a small gold nugget? The problem there is if you want to do tests and put them on the Internet, use something nearly everyone can acquire and use to repeat the test. Otherwise you always have an out when results differ. Anyone should be able to do what I do and get the same results. If not, then we have uncovered a case where two examples of the same detector differ in performance, which in itself teaches us something about the brand. The Bic does a fine job of representing a small non-ferrous target. In case you were wondering, tungsten carbide reads low conductive just like gold, so that is not messing with the signal.

My other standardized test item is the US nickel which does a fine job of mimicking a roughly 1/4 oz gold nugget.

The initial result? In all metal, the F75, Nokta, and V3i all easily hit the ballpoint. The CTX? No signal.

Where it got interesting was in the discrimination results. Specifically as in setting up for dual tone ferrous/non-ferrous responses. The Nokta in basic boot up DI2 dual tone mode gave a clean non-ferrous tone and VDI reading of 44. The tones split at 40 with lower numbers ferrous and higher numbers non-ferrous, so a good solid non-ferrous indication.

The V3i in 22.5 kHz mode gave it a solid VDI of 2. The White's splits at zero with positive being non-ferrous and negative numbers ferrous. Good clean hit. Better yet, when turning off VDI normalization it kicked the native 22.5 kHz VDI up to 10 which is really good.

The F75 SE? A solid VDI of 1. The problem is about 12 and lower would normally be ferrous. Many people will drop the setting to 6 knowing the F75 will call smaller non-ferrous targets as ferrous. Unfortunately in this case it drops it right down to the low end of the ferrous readings, guaranteeing a low tone ferrous response. This is an "not upgraded" F75 and I am anxious to see if the new FA mode brings the VDI up on this test item.

My primary goal here is bigger gold using bigger coils, but the more capability packed into one unit the better. It is no secret the 19 kHz Gold Bug Pro will identify small non-ferrous better than the 13 kHz F75 so no huge surprise here but I can't help but be disappointed. The F75 all metal audio response is just fine but if I want to dig everything I will use a PI. Not any surprise about the CTX either since multi-frequency is not known for being hot on small gold. The V3i ability to run single frequencies gives it a clear edge here. In ground tests often even things up or stand them on their head but for this real basic round one, the win goes to Nokta and V3i.

[Steve Herschbach]

Moving along, here is an update. I added a photo in the original post with exact weights and dimensions of all large coils with an extra note in the test on dimensions. Here is a shot of the four small coils and all four detectors with small coils set up. Weights of detectors as pictured with small coils:

Fisher F75 with 5" round DD coil 3 lbs 4.6 oz

Nokta FORS Gold with 4.7" x 5.2" DD coil 3 lbs 15.0 oz

White's V3i with 4" x 6" DD coil 4 lbs 0.4 oz

Minelab CTX 3030 with 6" round DD coil 4 lbs 12.2 oz

[cobill]

"I  am seeing similar situations here down south, especially in California. Places where 150 years of mining has left ferrous trash galore. What I am looking for is a way to narrow things down a bit in some situations. The idea in some places with unknown potential is to scout first with the VLF, and then, if any gold is found, to switch to a PI and hammer the spot.."

 

I had the same thoughts while working a trashy tailing pile in AK this summer...what is the best way to work an area where the GPX-5000 finds tons of targets and they are mostly deep ferrous targets. I was worn out digging railroad spikes at 18"- 24". I tried a VLF, but got frustrated very quickly. Is there a basic setup for VLFs or one superior VLF that can be used to make it easier for searching trashy areas?    

The only basic setting I've heard of are to adjust the discrimination to just allow a nickel to be heard. Other ideas are to just set the discrimination to a certain number and dig everything that comes through. My test nugget was no help! 

Steve, I'm sure you have a better system that we could all use.

 

Bill

[Steve Herschbach]

There is no one clearly superior VLF or this whole thread would have no purpose. They all are very good or all just as bad, depending how you want to look at it. In Alaska the White's MXT was the go-to machine but any good mid-frequency VLF can do the job. My preference is for a dual tone arrangement, low tone ferrous and high tone non-ferrous, which is just what you get with the MXT Relic Mode. See http://www.detectorprospector.com/gold-prospecting-equipment/whites-electronics-mxt-metal-detector.htm for MXT tips.

A US nickel is equivalent to about a 1/4 oz nugget, so as long as you are comfortable rejecting all nuggets under 1/4 oz that might work. Honestly, that is a coin hunter setting, not a nugget setting. For nuggets, you want the absolute bare minimum ferrous rejection possible, or about enough to tune out a small nail.

That will eliminate most ferrous junk but certainly not all. Steel bolt or large spikes, large washers and nuts, steel plate, etc will still sound good. A VLF can greatly reduce the amount of junk you will dig compared to a PI but you will not eliminate all ferrous targets without eliminating nearly all the gold also.

It actually just depends on the location. Some places you just have small ferrous stuff that is easy to deal with. Other places are full of big stuff, and that is a problem no matter what.