19 replies to this topic

[ddmk6]

Hello All,

Getting ready to pick up a large round Mono for my GPX5000. I have an 12 x 18 goldstalker mono that I'm very pleased with. Just found a .8 oz chunk in AK with it last week. That piece was an easy 2' deep, maybe 2 1/2'. Barely a whisper until I moved about 4" of dirt.

Anyways...I was wondering if any of you have used the 22" mono goldstalker on your GPX5000. I'm in a toss up between the 18" and 22". I have an old patch that's produced some really nice chunks. It's been hammered to death, but I bet there are still some hiding way down deep.

Is the 22" very stable or can it be finicky. The 12 x 18 is pretty sensitive to bumping and falsing. When I really have it cranked up I have to be really careful not too bump it on a rock.

Would love to hear your experiences.

Thanks,

[FlakMagnet]

Hi ,

I am sure you probably know this but it bears saying
the bigger the coil the more interference-prone it is.

I hear the 18" round Advantage coils are good
but no first-hand knowledge.


All the best,

[Rob Allison]

Hello ddmk6 & Flak,

Funny you mentioned this coil. Last weekend I was just about ready to hike to an old patch a friend told me about that has never seen a big coil over like 11-inch round. He said the spot was known for big nuggets, 1+ ounces and bigger and recommended a big coil. The spot is off the beaten path and requires a good hour hike. I'm looking forward to trying this very coil on this patch along with several others.

I have done some testing not far from my home and the depth results were very impressive using the "Normal" timing feature on the GPX5000. If I can pull a nugget or two from a few of these spots I will re-visit a handful of old patches that have produced deep nuggets in the range of 1/4 and up.

I have sold a handful of 22-inch Round's along with the 24-inch ellipticals, but most don't want to post their finds or reports.

Take care,

Rob Allison

[ddmk6]

Hello ddmk6 & Flak,

Funny you mentioned this coil. Last weekend I was just about ready to hike to an old patch a friend told me about that has never seen a big coil over like 11-inch round. He said the spot was known for big nuggets, 1+ ounces and bigger and recommended a big coil. The spot is off the beaten path and requires a good hour hike. I'm looking forward to trying this very coil on this patch along with several others.

I have done some testing not far from my home and the depth results were very impressive using the "Normal" timing feature on the GPX5000. If I can pull a nugget or two from a few of these spots I will re-visit a handful of old patches that have produced deep nuggets in the range of 1/4 and up.

I have sold a handful of 22-inch Round's along with the 24-inch ellipticals, but most don't want to post their finds or reports.

Take care,

Rob Allison

Thanks for the reply Rob. I'm very interested in your results. I want to buy either the 18" or the 22" within the next week and 1/2 so it will be there when I get home. I figure if the 12 x 18 will find the chunk in the pic at 2+ feet, the bigger round should be really impressive! I just don't want to end up with an unruly coil that I'm fighting all the time to quiet down. The 12 x 18 is outstanding in fine gold timing. Especially at the AK location. Ground is not hot at all.


Please let me know how it goes.

Thanks,

Kenny

Attached Files

•  nugget.jpg   198.01K   43 downloads

[FlakMagnet]

Hi Rob,

Of all the dealers I know of,
you seem to have the best nose for gold.
I will be interested in your thoughts on the coil
and I wish you luck at that patch.



Flak

[Rob Allison]

Hello Guys,

ddmk6 - Very nice nuggets you found there. The general rule of thumb is the rounds always get a bit more depth over the ellipticals of similiar or like sizes. To increase depth, you would need to get a larger elliptical or round. However, the nuggets have to maintain a certain size or become larger to get more depth also. The larger nugget you have displayed would be found deeper, maybe just a few inches or so with a larger coil.

Flak - Thanks for your comments. I'm excited to get out with the new coil, but it's been so darn hot here. Most of the good patches are a good hike from the vehicle, just can't pack enough water to make it worthwhile. One good sized nugget I will pay or the coil, maybe even a detector!

As for the nose for gold, I think we all have it, just a matter of how much someone applies what they have learned. I've been tromping the hills with a metal detector for a good 15 years now.

Talk with you both later,

Rob Allison

[FlakMagnet]

Hi again Rob,

When I drove race cars they used to call it seat-time.
In detector language it getting out there and using what you know, yes...

Still, that being said, there's no denying you find more than most.


Flak

[ddmk6]

Thanks again Rob. I was really surprised to find the larger nugget at 2+ feet. In fact I almost dismissed it as ground noise, glad I did a little digging. But the ground at that location is really quiet. You can't even find black sand when you pan.

The other patch I want to have a go at with the larger round is a lot more mineralized, probably wouldn't have been so lucky there. I'm pretty sure it has not been worked with a newer machine and a large coil though. I know it's been hit with a GP and a UFO. I think the 5000 will have an edge though. Worth a shot. I just don't want to go so big with the coil that I'm fighting ground noise. That may be all I have to tell me something is there :-)

Kenny

[highbanker58]

Rob- I have read there is a formula for the comparison of elliptical coils versus round coils. What round coil would have comparable depth to the 12 x 18.5 Coiltek? Dave

[Rob Allison]

Hey Dave,

I believe the formula you're referring to is the elliptical one:

Take the length + width and divide by 2. For example, the coil you stated, which is the elliptical 12x18.5 would be -

12 + 18.5 = 30.5 divided by 2 = 15.25 inch round. So if the forumla is correct, a 16-inch round Mono would get the same depth, if not better than the 12x18.5 elliptical.

Hope this helps,

Rob Allison

[ddmk6]

Well...I went out and played with the CT 22" round mono. I guess I need to spend some more time with it. I took it to a test area I have set up in moderately hot ground. I started off in fine gold. Had to turn the gain down to 8 so the EMI would settle out. Then tried normal timings. Deep etc., etc. I just played around with the settings until I got the best response I could from a 1 oz. nugget. My initial response would be disappointed. I can't seem to get any more depth from the 22" round than I can with the 12 x 18 goldstalker. I'm sure it will take me a bit to figure this out, but so far I'm not sure it was money well spent.

Kenny

[Rob Allison]

Hey Kenny,

I know a 22-inch round Mono should get more depth over the elliptical you mentioned, but it's not going to be huge (3-4 inches). My guess is maybe an inch or so at best. If you had a huge nugget then you might see better results.

The key with larger coils and depth is to hunt slow, listen for breaks in the threshold and scratch and dig anything that even sounds like a potential target. I'm sure you already know this, but just tossed it out there for all new guys/gals.

Talk with you later.

Rob Allison

[ddmk6]

Thanks Rob,
I actually spent about 10 hours with this coil today. I dug some more slots in my test area and set the 1 oz piece in a slot where I could just barely get a threshold break with the 12 x 18. Then I switched to the 22", I tried many combinations of timings. The normal timing seemed to hot for the ground I was in. I finally settled on fine gold timing. I could get a definite signal using fine gold with the gain at 11, audio deep, stabilizer 8, basically the same settings I run the 12 x 18 at. There was a definite improvement in the signal when switching from the 12 x 18 to the 22". Not as big a difference as I had imagined, but it is a difference.

I was able to pull out a couple small pieces from a well beaten patch as well. One is .6 grams pretty much on the surface, more quartz than gold I think. That impressed me that I was able to hear that one. The other one is 2.8 grams from about 6 to 8", very faint signal as well.

Your right on the money about move real slow. Anything else and it would give to many false signals. And of course, listening for the faintest changes in the threshold. As I said this is a well worked patch, so there really aren't any good clear signals. I'm sure after I get to use this coil more, I will find some settings to get a little more performance from it. Heck I just bought my first minelab in April, so I'm still learning the ropes.

Any advice on settings are always welcome.

Thanks,

Kenny

[ddmk6]

Put in another 10 hours with the 22" yesterday. The gold you see below is the total for 2 days. So far nothing has been deeper than 8" Tried using different timings and working the same areas multiple times. The timing I end up defaulting to is the fine gold timing. It seems to be the most stable and reach the deepest. I can not ground balance with the normal timing, even with the gain below 8. Ground is just too much for it.

As I'm sure you guys know, this coil is really sensitive to lifting the edge when swinging. It really likes to be parallel with the ground. Takes a good deal of concentration and coil control to make it happy. It's not very easy to work with and I'm not sure there are any benefits for the location I chose it for. There is quite a bit of brush and tree limbs in the area. Maybe for an area like Rye Patch or in Arizona it would be a little easier to use.

Kenny

 2 days.jpg   150.2K   63 downloads

[FlakMagnet]

Hi Kenny,

I think most of us would consider that a pretty good haul for a couple of days...
It sounds (and looks), like you're doing everything right.

Best of luck.

[ddmk6]

Thanks Flak. Don't get me wrong....I'm very happy for the gold for 2 days. I think I would have had the same results with the 12 x 18 though. I have some more experimenting to do before I can know for sure. The 22 surprised me by picking up the .6 gram piece for sure. I'm sure it will just take some playing around to figure it out.

Take care,

Kenny

[Beer Beeper]

Hey Kenny,

I know a 22-inch round Mono should get more depth over the elliptical you mentioned, but it's not going to be huge (3-4 inches). My guess is maybe an inch or so at best. If you had a huge nugget then you might see better results.

The key with larger coils and depth is to hunt slow, listen for breaks in the threshold and scratch and dig anything that even sounds like a potential target. I'm sure you already know this, but just tossed it out there for all new guys/gals.

Talk with you later.

Rob Allison

I do not agree with JP that round coils have more depth(over elliptical coils) due to they accept the return of the pulse signal better. But I think rather the depth depends on area of the magnetic field.

I also do not agree with the formula for an elliptical where, length + width ÷ 2 = equivalent round, although it is a common held opinion.

The way to tell the depth of an elliptical coil as compared to a round coil is the area of the coil.
Area calculations:
round(circle) Area = (pi is 3.14) x r_{(radius) x} r_(radius)

elliptical(also known as an ellipse or oval) Area = (pi is 3.14) x r_{1(radius of width)} x r_{2(radius of length)
(Another formula for Area of an elliptical I heard was: length x width x .8 = Area)}

Someone explained a 12 x 24" has about the same depth as a round 16". Also someone explained something like this:
The bigger the coil then the deeper it will detect the bigger nuggets but the shallower it will detect tiny nuggets.
The smaller the coil then the shallower it will detect bigger nuggets but the deeper it will detect tiny nuggets.

I have a NF 12 x 24" and 25" monos. It depends on surface area of the gold facing the coil, but on typical nuggets about -2 oz and under there is not a huge advantage for a big round coil over a big elliptical. But on about a bigger +6 oz nugget a big round coil starts to shine as much better. If I were you I would have bought the elliptical 14 x 24" instead of the round 22". Yes the 22" will pick very small gold on the coils edge but the 14 x 24" has more sensitivity(depth) to smaller gold and the most depth you want for the size of gold you are looking for, the best of both worlds. This is my opinion and others may disagree.

Someone else also explained that there is almost no depth advantage on coils over 18" round, just more ground coverage. Yes he is right on the most common(over +99%) gold sizes on the goldfields, unless the very rarity if the gold gets really big then there is an advantage of coils over 18" round.

[Rob Allison]

Hey Beer Beeper,

Interesting ..... I have to agree with some of the stuff you mentioned. There are so many variables, many too hard to determine what is best. I do agree with the type and size of the gold (surface area) plays a huge roll.

I think you just have to go with what you believe is best for you. I think for a good portion of all the gold laying within detector range, a coil in the range of 14-18 inch (round or elliptical) will do just fine.

I think some loose sleep over this subject thinking they are missing gold.

[DolanDave]

HI ddmk6, and all,
I also just purchased a 22" goldstalker coil from Rob, and I am using it on the Minelab gpx5000. The coil is awesome!! The only flaw I think coiltek should fix, is it stresses near where the rod is attached, and seems to open up some allowing dirt to get in the coil, a little tape will fix that. I wear a fishing pole type harness when I hunt, in which I had the wife make for me, which removes the weight to my arm, and places it on my hips. The coil is pretty sensitive to small gold, punches deep, is pretty good at being stable, but I would recommend only using on flat surfaces, no going up and down hills. I have only used at Gold Basin so far, but would love to try other places.
Dave

[Capt. D.]

This is all very interesting. I just purchased a 17" x 10" Nugget Finder Coil. I'll get out when I can to see how different it will be in comparisn with the stock 11" Round DD and a Platapus 12" x 8.5 ". Actually here South of Houston Tx. there is no gold to find but I've been relic hunting with the Plat. and the Commander.

Bill