So Let's Open That Old Box Of Arguments About Iron Mask, As I Got A New Angle On It To Debate. :biggrin:

[Critterhunter]

Some of you are probably aware of the old back and fourth arguments me and Crazyman and a few others used to have about Iron Mask. Me, I took the slant that Iron Mask on the Sovereign has unique ability to pull non-ferrous signals out of iron, while Crazyman said Iron Mask was just plain and simple built in high iron rejection. Well, that doesn't jive with the results I've got, as I've dug a lot of coins in iron with the Sovereign that I've never dug with other machines whether they are using little or no iron rejection or not. Think about it...Why make the only machine on the market with built in non-adjustable iron rejection unless Minelab had a trick up their sleeve? Just doesn't make sense. In fact, if you read some of what Minelab has to say about their BBS machines and BBS's Iron Mask On feature, they sort of imply that by saying something like "the ability to pull non-ferrous signals out of ferrous ones". Sounds like more than simple iron rejection to me.

Now, I'm not talking about a coin directly below a nail that is inches shallower than the coin. Detection fields stop and interact with the first target they see, period, with no further ability to hit something shallow and also reach and see something deeper at the same time. I'm talking about that rare situation where a coin and a nail (or just iron in general) are laying at the same depth, and so close that they are probably touching or even overlapping, and so can both be washed in the detection field at the same time when conditions are just right. When that happens, even then, a good sharp field such as that of the 12x10 can easily wiggle over one and isolate and see it with proper coil use, and then onto isolate and see the other. But, there's a point where both can be in the field as "one" at the same time. That's when I think Iron Mask does it's magic...

But anyway, that debate went back and fourth, and I never really thought much about it until the last few days, as what matters to me is results and not so much WHY those results are happening. Then, it struck me...On the FBS machines they at least attempt to give a reliable ferrous reading for a target along with it's non-ferrous (conductivity) value. If that is possible, then why isn't it possible for Iron Mask on the Sovereign to also be able to tell ferrous/non-ferrous qualities about a target? The only difference is that on the FBS machines it's trying to quantify a value for the ferrous number (which is still rather unreliable as a digging tool, but it tries), while on the Sovereign it's not wasting time to try to assign a value to the ferrous values of a signal, but rather it's just trying to pull any non-ferrous signal out of it and sound off and report it.

Now, somebody tell me why one is possible (attempting to report ferrous qualities) on an FBS machine, but that it's impossible that the BBS machines are also able to at least see and ignore the ferrous signal (hence what Iron Mask is doing...It's not so much ignoring "iron"....A play with words but a better way to put it is that it's recognizing and ignoring ferrous parts of a signal)...And do it's best to sound off to and report any non-ferrous qualities to the mixed (coin/iron) signal. That's what I think the answer is, and I only wish I would have thought of it back in the day to debate with Crazyman on. It is possible to see ferrous/non-ferrous properties of a mixed detection field signal that is being received. Obviously it has to be or the 2D discrimination on the FBS machines wouldn't exist. I always wondered why Minelab was the only one to build in high iron rejection on the GT/Xcal. Now I think I know the answer to that. They did because it really didn't matter with the ability to pull non-ferrous signals out of it.

 

[imalookin2]

Possibly it is the 28 frequencies and the broader spectrum of those frequencies make a difference. The Excal and Sovereign use 17 frequencies. More frequencies means more accurtate results for the computer. I think this is why the 3030 will be a top dog if you can afford it. I won't buy one, I like simple machines like my Sovereign. It works just fine for me and it will for a long time.

 

[imalookin2]

Sorry I clicked twice. "-) Nothing here but static.

 

[Critterhunter]

Well, there is some debate on this but from what I've recently read from somebody who scanned the frequencies of FBS and BBS machines, this person says they are both putting out the exact same frequency spectrum. If that's true, then it was speculated that it's not a difference in what they are transmitting, but rather just what parts of the signal they are differently paying attention to. That could be why *some* say BBS is the smoothest/deepest machine they've ever used in some soils or at some beaches, as perhaps the lower frequencies being paid attention to are less effected by certain forms of mineralization or salt water? I know that other non-Minelab machines using high frequencies never got the depth in my soil that some of the low frequency machines I owned did. Just a guess...

 

[Ism]

FBS goes to 100khz, BBS goes to 25.5khz

http://www.minelab.com/consumer/knowledge-base/minelab-technologies

 

[Critterhunter]

Yes, Ism, I'm aware of what Minelab claims the frequency range is for BBS and FBS. But, I just read a new thread somewhere where a guy scoped the TX signal from both platforms, and he found that they were both putting out the exact same signal and frequency range. At least, I'm pretty sure that's what he said unless I am mistaken, as I just sort of glanced over the thread and didn't read every single detail as I was rushed for time. If I can find that thread I'll post a link to it, or if somebody knows of it then please post the link. That was the first time I've heard such a thing, so it was kind'a shocking to me. I know there's been debate about just how many frequencies are actually transmitted, as well as just which ones are paid attention to, in the past...But this was the first time from memory that I saw somebody say the TX signals were identical between them. If that's true (and I read it right), then what can explain the differences between the two systems? I would guess (and he might have in that thread as well, can't remember) that the difference is just what frequencies are being paid attention to and processed by BBS and FBS. *IF* all that logic follows, then perhaps that's why there are differences in how they both perform *for some people* *in some soils or sands*?

 

[Critterhunter]

Well, just did some searching the net and I can't find that recent message I read claiming that FBS and BBS had the same TX output signal, so I'd take that with a huge grain of salt until I can find it again and post a link. I know I read that in a new message somewhere recently. Just can't remember where. I did find a blurb on elsewhere where a guy did say both TX signals are the same, but that's all he said and didn't go into details, so that statement is pretty well worthless, but the other one did go into detail that I'm still trying to find.

I would figure that in order to process higher frequencies on the FBS machines they in fact have to be transmitted, so it wouldn't logicly make sense that BBS and FBS have the same frequency spectrum. On the other hand, I guess they could be identical and it's just that FBS is paying attention to higher areas of the spectrum in what is received back and processed. I would figure that's the only way it could be true that both signals are the same in the transmit part of it, but that just doesn't jive with Minelabs claims of 25khz being transmitted on BBS and 100khz on FBS. Unless both signals are the same range (up to 100khz), and it's only that BBS pays only attention to stuff below 25khz, I don't see how it could be true.

 

[Ism]

Ok, I misinterpreted what you were implying. I believe they are identical until the frequency gets past 25.5KHz then there is either one or two frequency bands after that. But it could account for the difference between the two. It wouldn't be out of the realm of possibilities for Minelab to allow an FBS detector to operate as a BBS by allowing the user to switch off the processing of signals higher than 25.5KHz. From what I saw on the scope, it steps through the frequencies and then repeats. It looks like the signal is throbbing. So unless ignoring the higher frequencies would cause abnormal behavior, they could create a detector with selective performance options. Even allowing the user to knock out low or high freqs or even select a center band of frequencies. Might be interresting, or maybe they already tried it and found it isn't a value added option. Don't get me dreaming up ideas that I can't create...lol

 

[Jack Flynn]

CH what I see is iron mask just knocks the iron response out so all you see is conductive target responses. Tried it but really didn't like it although I could see where it could help a newby. Sort of beep and dig kinda. You really don't have to learn a lot of machines in a mode as such. Just a signal and dig it. What a lot of people don't learn when doing this with a lot of machines is how to really use the machine to your advantage. Take the ETrac in TTF, just beep and dig essentially. The GT would be the same way, just response and dig. IMO lots to be missed in a mode like this with many types of machines. I really like to know everything in the ground when I'm detecting. All of it tells me something about where I'm at.

 

[Critterhunter]

Jack, I agree with wanting to hear it all. I've always hunted that way, but I *have* to have tone alerts to do that, so I rarely hunt in all metal or PP mode to hear the iron. Without tone alerts that's when I would crank up discrimination on some machines to not hear the iron, but with tone alerts I want to hear it all myself so I wish it could be lowered to hear iron. Still, I don't worry about it hurting me in unmasking, as I think Iron Mask on the Sovereign is in fact doing more than just blocking the iron. It's trying hard IMHO to report any non-ferrous signals mixed in with ferrous ones. Like I said, it is possible to see ferrous/non-ferrous qualities of a detection signal, as is evident by the FBS 2D discrimination. It's not very reliable as most Etrac guys especially ignore it and only watch conductivity most of the time, as the ferrous number can range wildly on it. Either way, just saying I think Minelab built in the iron rejection on the Sovereign because they had other ways to pull coin signals out of iron besides lowering iron rejection. In fact, if you read the tech article on their site I think they reference the ferrous/non-ferrous signal processing thing about BBS technology. I'll see if I can dig up that info and post it as it's been a while since I glanced at it. I'm going from memory here so I might have the details wrong.

 

[crazyman]

Do we really want to bring this up again? It was never an arguement about if it worked but more on how it worked and where it works. Iron mask is not some magical feature. It's nothing more than a shift in the discrimination range creating less bias towards certain iron "in the ground" along with mineralization including hot rocks. It's that simple. The more bias you have towards small iron the more masking you have of targets that are in the same detection field of the coil. Iron mask on can have the opposite effect when it comes to high mineralization. Less bias or filtering of high mineralization creates more masking and less depth in some circumstances. There is a fine line when it comes to balancing or filtering out mineralization. The only way you will see this is in the field under actual hunting conditions. You can't use controlled testing aka air tests to see how iron mask actually works. If you remember right I completely 100% debunked the Minelab video demonstrating how the coin disapeared when he turned iron mask off in that controlled test.

 

[Critterhunter]

Look who's back! Been a while guy, how you been? I just checked your posts and the last one was around the time you disappeared, so I'd assume somebody tipped you off that the old Iron Mask debate was going on again and your name was mentioned? Good to see your face again. It should make the forum more interesting if you are kicking around in here again. Good to have you back!

And let's get this one rolling right away. Dug this out of a little tech article written by one of Minelab's people...

"Almost all Coin and Treasure detectors have discriminator controls for selecting desired properties of a sought metal target. The properties that may be selected are

 

[Neil]

Do we really want to bring this up again? It was never an arguement about if it worked but more on how it worked and where it works. Iron mask is not some magical feature. It's nothing more than a shift in the discrimination range creating less bias towards certain iron "in the ground" along with mineralization including hot rocks. It's that simple. The more bias you have towards small iron the more masking you have of targets that are in the same detection field of the coil. Iron mask on can have the opposite effect when it comes to high mineralization. Less bias or filtering of high mineralization creates more masking and less depth in some circumstances. There is a fine line when it comes to balancing or filtering out mineralization. The only way you will see this is in the field under actual hunting conditions. You can't use controlled testing aka air tests to see how iron mask actually works. If you remember right I completely 100% debunked the Minelab video demonstrating how the coin disapeared when he turned iron mask off in that controlled test.

good post crazyman. sometimes we gotta wear boots in this forum it gets so deep