GM2000 Three Ground Type Frequencies

[Jeff McClendon]

Reply from Minelab about if Benign, Normal and Difficult on the Goldmonster 2000 are all using Multi -Au. There was some speculation that Benign was just using a single frequency.

 

Jeff,

Benign, Normal and Difficult ground don't change the frequencies used.

Multi-AU essentially just is saying that this detector has that gold frequency, while also providing a target ID. 

--
Kind regards;
Nolan
Minelab Customer Care

[mn90403]

2 hours ago, Jeff McClendon said:

that gold frequency

Do you know what 'that' means?

[Wild Bill]

Here’s how I understand this.  Generally VLF frequencies from 5Kh to say 12Kh have the most depth but lack fine sensitivity.   Low frequencies from 40Kh to 80Kh have greater sensitivity but lose some depth.  The MD-20 at 300Kh is the most sensitive but is restricted to high grading with its small probe coil.  Certain frequencies are a little better at detecting certain metals based on conductivity.  The SMF detectors are like using several detectors at once without having to come back with other detectors using different frequencies.  Excluding PI with its depth advantage.  

My wife and I both use Garret AT max detectors with having only 13.6 Kh.  For some reason these detectors will do quite well at detecting gold down to .05 gram using a 5x8” DD coil.  I haven’t thoroughly tested it except on nuggets from .05 to .8 gram nuggets I’ve found with my Nokta Gold Kruzer.  I’ve tested the same nuggets on the ground and slightly buried on other detectors with small coils and with frequencies from 14 Kh to 18 Kh that wouldn’t detect the smallest.  Not sure why the AT Max acts like a prospecting detector without having a higher frequency?  I plan on testing it and comparing it to the Gold Kruzer on depth in my Northern Nevada mineralized soil.  The Gold Kruzer at 61Kh and the Max at 13.6 Kh are at two entirely different frequencies yet so far behave the same.  I’ve only buried these small nuggets a couple inches in mineralized soil and noted the AT Max ability to clearly detect them.  So I told my wife if you go with me prospecting, go ahead and use the Max with 5x8” coil, it works.  What its limits are I don’t know because I’ve yet to thoroughly compare it.  I’m curious to see which detector has the most depth since both detect the same nuggets.  I suspect a cut off approaching speck size dust gold with the Max which I’m not entirely interested in chasing something that should be dry washed or panned.  

Like I mentioned in another thread, I’d like to see how much better the GM2K is compared to my Gold Kruzer and my Kruzer compared to my AT Max.  One being SMF and the others using single but far different frequencies.  All having different electronics, coils and processing.  My wife had wanted a Nox 800 and has been eyeing the Manticore but has been busy with grandkids and a part time job with organic farming so she didn’t pull the trigger.  I mentioned the Nokta Legend and now the Legend 2, to keep an eye on that.  I’ve been distracted as well and can’t justify another detector at the moment.  I want to detect more but get things out of the way first.  Maybe a light PI in the near future.  

[EL NINO77]

 

 

For every detector, there are 5 factors to consider that affect the detector's performance on a specific type and size of target:
The:

1st Factor is the frequency/multifrequency used.
2. Factor TX power and detector electronics
3. Factor is detector software
4. Factor Size and type of coil..
5A Factor Type and mineralization of terrain

if the compared detectors have quite similar factors 2,3,4...
Then factor 1 the frequency / multifrequency used will have an impact on the detection and strength of the detected target's response...

Let's say that 1 frequency 13-14 kHz is quite.. universal for a wide range of sizes, say from 0.1 grams of pure ore... to massive silver coins the size of a US dollar.. let's say in moderate or slightly mineralized terrain... I have 0.1 grams of gold at a depth of 10cm.. on my test field.. can powerful detectors detect such targets,,

Next frequency 13-14 kHz can well unmask a certain range of target sizes.. in iron..It comes from my testing..

I myself have used the 1F frequency of 14.4 Khz with great success.. in detecting gold coins, and other nice targets...let's say in moderately difficult terrain,,

However, if we start taking into account factor 5. type of terrain and its mineralization... there is a need to use a slightly higher frequency of the detector's work.. because the detection and identification of targets when using the standard frequency begins to fall into the zone of identification of iron targets..,, especially for deeper targets..., such as targets of smaller size - especially small low-conductivity targets..already at low and medium depths..
Here, a great deal of work will also be done by optimizing the detector software, which can compensate for the negative influence of the terrain on the detection of such a target..and the multifrequency of the detector can make the best signal reading terrain from the target signal and best calculate the correct VDI target..

Because the optimal frequency inductance of a very small low-conductivity target requires using a significantly higher detector operating frequency to achieve optimal results..

The smaller the target, the naturally lower its conductivity, and its optimal inductive frequency is higher,,.. so small targets need a higher frequency for optimal detection of such a target.. in the range of 40khz, 60khz, up to 80khz.. even over 100khz..

That is why modern single-frequency and multi-frequency gold detectors use relatively high frequencies and it is the right way ...

I use high-frequency detectors to check the terrain,,, primarily to unmask in the iron detection of other targets on the terrain and already detected by other detectors.. so that I know which targets passed... as well as the number of excavated iron that can give a good signal to a non-ferrous target..

That was also the case today, although a short detection. Due to inclement weather... on a stone road... using a detector operating at 74 kHz..

dug 4 pieces of small lead shot from this hole.   

---------------------------------------------------------------------------------------     The total number of dug targets... 2 pieces of more massive iron that gave a good signal... and 7 pieces of small lead shot.. one piece is missing in the photo...
Now another fact is confirmed... and that detectors with a frequency of up to 18 kHz to 54 kHz and multi-frequency up to 40 kHz did a really good job... because larger non-ferrous targets are still missing... we'll see later when I completely finish detecting this stone road.. on a frequency of 74 kHz..                                         

[Wild Bill]

This is interesting to me.  Those that have experience with the GM1K but have upgraded to the GM2K notice a big improvement in target ID.  Is it a result of SMF or a difference in processor?  Both my single frequency detectors I mentioned in my previous post have target ID that are reasonably accurate.  Aluminum and solid steel can give a good ID and tone but sometimes the solid steel or iron tone is different in that if it were on an oscilloscope, it might resemble a square wave.  It’s a high tone like copper or silver because it has pretty good conductivity compared to mid conductors like gold, lead and brass.  I don’t own a SMF but I notice those that do on this forum still dig plenty of trash despite the technology.  I do too, especially aluminum and some solid nails.  I notice the difference in audio but don’t take it as reliable.  I posted this on another thread about detecting out on Northern Nevada’s Forty Mile Desert.  A highly mineralized area with black sand, salt and alkali leaching to the surface, damp from rain, littered with pea gravel hot rocks from a volcanic cone and in some spots covered with rusted iron pieces from broken down gold rush covered wagons.  Seems like a challenging environment.  For fun and curiosity, in one area I went through it with my AT Max in Custom with Iron Audio set at 40!  Lots of low tone scratchy grunts.  Brass came through with a clear mid tone.  One small hinge and two very small percussion caps about the size of a modern small rifle primer, one about two inches and one 4-5” deep.  The caps weigh .1 gram.  It will detect .05 gram gold with the 5x8” coil.  I’ve tested that but nothing smaller.  

So I’m only throwing this out here as a comparison.  I don’t own any SMF but you guys do.  Plus I trust you guys because of your years of experience and the fact some of you are trusted by manufacturers to do honest field testing and give feedback.  
The AT max isn’t the most beloved detector yet I’ve found it can handle terribly mineralized soil, has impressive sensitivity, depth, target ID, often distinct tones and It’s very easy to use.  So I’m hesitant to dish out $1K or more believing I’m gaining much.  Not counting PI detectors of course.  Most of my prospecting is done with the Gold Kruzer, I have three coils for it but sometimes I bring that Max along with either the 5x8” or a 10x 14” Nel as it’s very sensitive for its size. 

With all that said, am I to believe that I’d have more depth with SMF than 13.6Kh?   
I can understand more depth with improved signal processing but not frequencies.  You can certainly go to a lower frequency but coils can also give more depth.  The advantage I can understand with SMF is depth with lower frequencies and sensitivity with higher, so you cover your spectrum with what VLF can achieve.  Yet some SMF detectors have goldfield mode that only use higher frequencies.  Making it into a single frequency like my Gold Kruzer.  I do use it for high grading ore, quartz or float.  I don’t see any advantage in SMF in that regard plus I’m not into detecting gold dust.  At least not yet.  Like 1 grain specs at 480 holes to the ounce.  But that’s just me… it works out for others for sure.  

So which brings the most improvement, better signal processors, improved coils or SMF?  Is SMF in goldfield mode (single frequency) better than a single frequency detector both being on the high frequency end?  Does the GM2K even have a single frequency mode?  With a SMF, why would need to shut off the other frequencies when gold prospecting?  

So I’m trying to understand what makes it a better detector.  The only thing I can see is you have a VLF & (higher frequencies) above 40Kh in one detector.  How sensitive are certain frequencies to different conductors?  How noticeable is it?  I do notice sensitivity to the size of metal targets with higher frequencies.  I don’t think I’ve noticed frequencies enhancing signals on different conductors.  I have noticed some detectors with higher frequencies and small coils won’t detect the small gold that the AT Max does. 

I like the echo wave audio though.  
Sorry this is so long winded but I’m just curious and thinking about this.  

[Wild Bill]

Thanks EL NINO77, I left my unposted comment I was working on as I’m doing something else and thinking about this.  So you are answering some of my questions.  Appreciate it.  

[Aureous]

So, that contradicts what Minelab staff and dealers were saying before and after the release. Who are we to believe? The changing between difficult and normal seems to suggest a frequency change because of the increase in sensitivity and mineralization handling but it could be a change of stability-retune and coil current too.... questions unanswered...

[Salone]

7 minutes ago, Wild Bill said:

Sorry this is so long winded but I’m just curious and thinking about this.  

You ask good questions, the kind that stir up good conversations. The replies will be most interesting. Thanks.

[phrunt]

I always felt Benign used SMF and as someone that uses it you get a feel for it.  In mild soil it's the best mode on the 2000, as is typical with all detectors with these "modes" the other modes lack the punch of Benign type modes in milder soils.  Benign feels like the other modes but with less ground filtering thus making it better in mild soils, it's certainly not some old, outdated technology mode that should be avoided.

The Target ID is OK and pretty accurate across all modes, It's shallow but OK, at some depth its pointless.