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Benefits Of Simultaneous Multi-frequency - Or Smoke And Mirrors?


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I've been a user of SMF detectors since they were first introduced waaaaay back in the early 90's with the Fisher CZ-6 and its' competitor, the Minelab Sovereign.  I went with the CZ-6 because it was in a better package.   CZ-6, CZ-6a, Explorer XS, Etrac, Equinox 800, and now waiting on a Deus 2.  I have a lot of years on them. 

There have been endless discussions on the marketing vs real world frequencies actually used.   All that aside, I ask these questions for a couple friends -

 

Below are some of the claimed benefits i hear related to Simultaneous Multi-Frequency.  If true, how?

How does simultaneous multi-frequency impact / improve dealing with the ground signal?

How does simultaneous multi-frequency impact / improve dealing with a salt signal on the wet salt water beach?

How does simultaneous multi-frequency impact / improve Target ID at Depth?

Any other claimed benefits I left out ?

 

I will direct a couple pair of eyes over here to evaluate your responses.

 

Thanks,

 

UtahRich - 

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You are asking very general questions about simultaneous multi frequency technology as if all SMF tech is the same. It definitely is not.

Most SMF tech will help saltwater beach performance compared to a single frequency detector by being more stable and by making the salt mineralization more invisible than a single frequency detector. A few SMF detectors also have user adjustable or automatic black sand compensation which basically lowers the strength of the transmit signal so you can keep detecting.

If iron mineralization away from the beach is the issue, most SMF tech up until the Equinox and Vanquish, did not perform very well and using a single frequency detector or a SMF detector made very little difference from my experience where I detect unless the targets where surface to 4" deep. Deeper than that and target ID was a 50/50 game of chance or much worse.

The Equinox/Vanquish Multi IQ technology changed that by specifically concentrating on lessening the effect of iron signals created by ground mineralization which makes iron mineralization much more invisible compared to other detectors. Minelab's Multi IQ technology basically ignores much of the iron signals coming from the ground itself and all of the simultaneous multi frequencies in each mode concentrate on the multiple non-ferrous signals. So, making iron mineralized ground more invisible and concentrating on the non ferrous responses for obtaining a target ID helps the Equinox see deeper targets and if they are non-ferrous....helps to identify them more accurately. Making the ground more invisible also helps with target separation and masking since the Equinox at least, can be run hotter and have faster recovery speed than previous Minelab SMF technology since ground iron mineralization is less of a factor. The Equinox (not the Vanquish) will also ground balance very well even in more extreme iron mineralization with little loss of transmit strength compared to previous SMF and single frequency detectors.

What form of technology is FMF in the Deus 2.............nothing definitive has been published by XP yet. Same for the technology in Nokta Makro's Legend. From the videos I have seen, both have very stable and accurate target IDs, are as deep as the Equinox using similar coils and both are a bit to a lot faster as far as recovery speed. Deus 1's speed and iron handling seem to have been transferred over to Deus 2 without missing a beat. I have not seen any testing of these detectors on ground or beaches that are highly iron mineralized however.

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Are these analogies helpful (although inexact)?

a) Four wheel drive or two wheel drive?

b) Two eyes or one; two ears or one?

c) Suppose you could outfit a headgear for night vision -- one eye views visible light through high collection efficient optic, the other eye similarly outfitted but viewing in the infrared.

Modern multifrequency IB/VLF is more complicated than these, but the principle is the same -- collecting information through two (or more) different viewpoints effectively provides more information.  At least that's my limited, simplified understanding of what's going on.  How that information is handled in software -- I think that is where improvements have been made recently and hopefully will continue to be made.

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I think the benefits of SMF have been discussed at length on this forum since the arrival of the Equinox and pretty much covered. My over generalized opinion is that if current SMF technology did not provide substantial benefits to detectorists these last 4 years, then detectorists wouldn't have continued to purchase SMF at such a sustained rate, and no other companies would now be rushing to put out SMF detectors and discontinuing many of their single frequency machines.

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Rich I have also been a long time user of SMF. I too bought the Fisher CZ 6a but quickly changed to the Sovereign because at the time I was primarily a beach hunter and it performed better for me in that environment. I kept the CZ 6a for park and relic hunting but it drove me crazy with it's love of deep nails.

So my take of how SMF performs in my area which as you know is the same as yours. Detectors such as the Fisher CZ series, Whites DFX and Garrett Apex will work on Salt Water Beaches with low mineralization better than single frequency detectors. They are quiet and ID targets pretty good. The Minelab Sovereign, Explorer, eTrac, CTX in my experience are deeper than the above mentioned detectors but once you add black sand, performance drops off quickly. Enter the Equinox and Vanquish now you have 2 detectors that are capable of handling black sand and salt. Target ID on those 2 machines stays stable almost to their full depth capabilities.

For relic and coin hunting the Fisher CZ series, Whites DFX and Garrett Apex are very poor performers in iron mineralization. The The Minelab Sovereign, Explorer, eTrac, CTX also suffer but not as bad as the above mentioned machines. Equinox and Vanquish are 2 detectors that are capable of handling iron mineralization and alkaline soils in our area. Target ID on those 2 machines stays stable almost to their full depth capabilities.

This last Fall I took a trip to a park that has given up some nice old coins in the past. I used the eTrac and the Equinox 800 to locate and compare signals. My goal was to see if I should keep or sell off the eTrac. I most cases coins that were less than 6" deep both detectors ID'd correctly. Coins that were more than 6" deep the Equinox had the clear advantage. In fact if I didn't open up the screen more on the eTrac, deep targets would get pulled into the rejected target range. Before I ever bought an Equinox I usually hunted with the eTarc using an open screen except maybe the the bottom 4-5 lines blacked out and the top left corner blacked out. anything that bounced above the bottom blacked out area in the 37 and above range I would still dig thinking it would be silver, a wheat or an IHP. But it was usually a crap shoot, sometimes a nail sometimes something good. So back to the comparision, deep targets the Equinox were much easier to ID as a good target. ID was more stable and I was able to tell whether or not it was iron. The eTrac on the other hand was just like Iike the above, hard to tell if I was going to dig iron or a good target.

Now we have 2 more SMF machines coming to market. From the looks of it they will both perform as good or better than the Equinox.

 

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Abenson,

Great post and I couldn't agree more.  I also have tested my Etrac against my Equinox and have realized similar results.  I loved my Etrac in its day but the way iron would give me a very slight high tone, making deep iron sound like a possible deep silver coin, just doesn't happen with the Equinox.  Yes on very, very rare occasions it was a deep silver, but more often than not it was deep iron.  The Equinox really changed the game.

I also concur with your views on the Fisher CZ, White's DFX and Garrett Apex.  In heavy iron they are just too much work.  It would be interesting to see if First Texas ever revisits the CZ series and tries to upgrade the technology.  Based on their complete lack of new technology development, save the Impulse AQ (which they brought in from the outside), I have my doubts if this will ever happen.  Similarly Garrett could take a run at the DFX.  As to the Apex, my hope is that Garrett takes the multi used in this machine and refines it for future models.  On saltwater beaches the Apex is a real sleeper, but inland it needs some work.

Bill (S. CA)

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I really appreciate the comments.  Some thoughts and comments are better when they come from another source.

Interesting how closely my experiences and thoughts parallel many of yours. 

I did leave my questions generic and vanilla as I didn't want to appear to be steering the conversation in any particular direction. 

Rich -  

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On 1/27/2022 at 9:47 AM, Bill (S. CA) said:

It would be interesting to see if First Texas ever revisits the CZ series and tries to upgrade the technology.  Based on their complete lack of new technology development, save the Impulse AQ (which they brought in from the outside), I have my doubts if this will ever happen.

Fisher did take a crack at updating the CZ series.  Product roadmap slides were leaked out at some type of internal conference, and it showed they were working on the CZX SMF machine(s).   The rumor is that they invested a lot of resources into this as their next flagship detector and for whatever reason (couldn't get it to work?), ended up scrapping the project and here we are with nothing. 

In light of all that we've learned about FTP over the past few years, and that their main business is contract manufacturing for other companies, then their industrial security business, and lastly their "hobby" business with these pesky metal detectors  I feel the best move FTP could do is sell off Fisher Research Labs so it could be it's own entity, not a C string line with obvious low priority.  They can keep Bounty Hunter, but split Fisher and Teknetics off so they can again be run as a real metal detecting company where metal detectors are the main priority, not night vision scopes and security.

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The CZX was not an updated CZ, it was a completely new design. It was specifically designed for prospecting and that's where it failed. I tried to get people to shift the project to coin/relic/beach but was unsuccessful.

FTP does contract manufacturing at the Juarez facility but metal detectors are still the primary business.

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  • Steve Herschbach changed the title to Benefits Of Simultaneous Multi-frequency - Or Smoke And Mirrors?

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