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Detector Unit Consistency (long Brainstorm)


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9 minutes ago, GB_Amateur said:

What's the scale of your map?  And what's your cell coverage?  Power lines? (I know you've talked about and shown us these in some of your nugget hunting grounds.)

Do you have any USA coins (or if not, how about an Aussie large cent -- I happen to have one of those)?  I think you're a good candidate for some standardized air testing.  We can compare notes (as soon as I get mine -- I hear Gerry has applied for a Cabelas outlet...).

It would be about 120 miles from bottom to top.    The drive along the lake from the small town at the bottom to the bigger town at the top is where I was testing out my Manticore on lake front beaches, it ran 35 sensitivity no problems, along this drive my cell phone coverage is very intermittent, for a good portion of it I have none.  There is no TV reception anywhere, we use satellites for TV.  There is intermittent radio reception, the middle of the lake drive there is usually none.  Nothing in the way of major powerlines around that lake drive, there is some normal power lines in spots like half way along there is a little hyrdo generator on a creek going into the lake.    It's a very low EMI area.

I have a few USA coins, not sure which ones, they're just ones I've found detecting, one of your zilcoins, a silver with a buffalo on it and a couple of others.   I don't know what an Aussie large cent is, but I have all of the Aussie currency, including the old stuff, easy to find Aussie currency here, I do have an Australian 1 cent coin if that's what you mean, the one with the possum on it.

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16 minutes ago, phrunt said:

I have a few USA coins, not sure which ones, they're just ones I've found detecting, one of your zilcoins, a silver with a buffalo on it and a couple of others.   I don't know what an Aussie large cent is,...

Oops.  My bad, it's an Australian penny.  (We over here don't know the difference.  😜)  Here's a picture of one similar to mine.  It's 30 mm in diameter:

Aussie_penny.jpeg.a246d1825eb5d2c990dd564a8c8115d6.jpeg

"Silver with a buffalo on it" -- what's the date?  Our 'Buffalo Nickel' (also called 'Indian Head Nickel') was minted from 1913 through 1938.  It's 21.2 mm in diameter.  All of our 5 cent 'nickels' are composed of 25% Ni and 75% Cu and are the same size so if you have that it's an easy standard.  (Well, OK, during WWII they were made of 35% silver, 9% manganese, and 56% copper.)  There have been recent 99.9% silver tokens minted with a buffalo on it, I think.  Maybe that is what you have?

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I'll have to find it, not sure where I've put it.  Hopefully not in the big tubs of coins I've found or I'll be searching for hours.

Yes, the Aussie One Penny, I find plenty of them here.   In the early days anything goes.  you could use just about any currency although British and Australian were the common ones.  This is an interesting read about the history of our currency.  https://www.rbnz.govt.nz/money-and-cash/coins/the-history-of-new-zealand-coins

 

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On 2/3/2023 at 11:44 AM, GB_Amateur said:

I go to Gerry's place and get 100 brand new 'identical' detectors.  (I know he has that many Manticores sitting there, getting a laugh out of it watching us on his waiting list.  😄

 

Boy I wish so.  I have thought about Cabelas as I have one within 5 miles of my place.  Why they're getting more than me is very frustrating.

Your article is interesting and I sometimes wonder myself.  Now as Steve H. mentioned, yes the older analog detector most certainly had good/bad/ok units and coils.  When I used to take groups of 12 customers to Alaska and England, most of us were running the same detectors and coils.  It was amazing what we learned from those comparisons.  As Simon brought up, we would think digital detectors and chipped coils would have less variance, or does it?  Realize these were assembled by a person.  What if a certain chip component ran out.  Do you stop production or order some grade B components and get the line up and running?

Chuck,  Quit making me worry about potential issues with a detector I can't even get..  That's like me trying to figure out how I'm going to stuff a 1 pound nugget in my mouth before I even find it.

 

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Here are some of my thoughts based on experiences with my AQ, CTX, Excal, Dual Field, and Equinox, and some miscellaneous comments:


CTX, Equinox

Bought it (CTX) used but very new. I wasn’t happy with the 11” and 17” coil performance in my low EMI park and got replacements from Minelab that were better. When I first hunted with the CTX at my local beaches I could rarely hunt with 30 Sensitivity - now it is the norm. I have two backup CTX’s that I don’t use but I suspect the Sensitivity is the same with them but I haven’t done an intense comparison. One of the 3 has newer design parts - haven’t heard of anyone comparing with an older one to look for differences. I am happy with my original CTX compared to all my other detectors - it is my go to unit. Did they lose sensitivity over the years due to aging components or is it that my brain is used to it?  When I tried to switch to the Equinox 800 I just couldn’t adapt. I wanted to run the Sensitivity too high. Sold it but later got an EQ600 on a trade and use it as my road trip detector - lighter, so I don’t have to take along the ML harness. Wish it had the gold mode though. 

AQ

I gave up (for now) trying to duplicate others air depth tests on a nickel. I could get a whisper but not the obvious tone I’ve seen others get. I’m told my headset should be replaced with a now custom better one.  Thing is that it is a normal test at Fisher and mine passed. Maybe they use an amplifier that replicates the higher sensitivity of alternate headsets. I’d rather they come up with a test saying the obvious 12-13” most of us get is the norm.  I’m not going to be finding whispers and digging each at 16” at my beaches. At first I was testing in my garage and the EMI was really hurting results. Calabash often mentions EMI while testing at his home. The effects of EMI will differ with each detector design…  

Excal

Known for finding gold, maybe while totally submerged (which I never have done), air tests of my two Excals really are depressing.  OBN has a post tx boost so maybe that helps a lot, but others are doing pretty good with theirs in a normal configuration so how do I check mine against theirs?
 

Dual Field

Kind of same deal as the Excal - air test on gold not good but KOB kills it with his and I got great finds with the pi pro I started with years ago.

Pinpointers

Oh yeah, almost forgot. I won a Minelab pinpointer at a GPAA show. Tried it on a gold nugget. The Garrett Carrot was Much more sensitive!  A bad one?  No way for me to be sure.

Noise Cancel

Anyone else concerned that ML NC numbers jump all over each time it is run?  Does this mean it’s not really effective? Does NC really work for you - does it repeat numbers and quiet things down? 

Summary

Yeah I’d love for someone to have a comparison site or forum section where we could compare detectors and develop standard tests - but in reality I have too many detectors and need to thin the herd. As far as EMI goes, I bought a Tri-field EMI meter that does a great job at sensing EMI. I drove all over, searching local parks, and finally found one nearby that tested really quiet. I had the best results with my AQ there (but others do just fine in their home or lab…). I don’t know if we would really come up with tests to say one detector excels others (Manticore vs CTX etc.) but we should be able to come up with QC standard tests along with videos that document them. Come up with standard targets and written procedures (settings). Post a video if yours does better and then we figure out why (or just get depressed).

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Don't worry about your Minelab pinpointer, they're an embarrassment to the Minelab name. 

I agree with the noise cancel, the quick noise cancel detectors are a gimmick.  The new Manticore noise cancel works, just as do the traditional noise cancels like the GPX 4500/5000 and GPZ.  I prefer the older detector style frequency shift over quick noise cancels, it works well.

With detectors being so different with performance in different locations from soil conditions and local EMI it gets very hard to do good baseline comparisons. 

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