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how many diff. friq. does fbs use at one time?

\"Carolina\" said:
Charles, thank you for your thoughtful input. I would remind you though, that soil, contains EMI, at varying strength and varies from area to area. This is why I noise cancel with my coil near or on the ground, not waist high in the air. This is where I hunt. Noise cancel is about EMI & RFI but it exists in the ground as well as the air. As far as the channel or frequencies chosen, I probably should have discussed mineralization as well. Wish you all the luck with your hunts!

Carolina

Ditto I always noise cancel with my coil sitting on the ground, motionless. But I do so because holding the coil waste high in the air, the coil basically being a big copper wire antenna, would catch EMI it won't see flat on the ground on edge to the EMI in the air.

I once detecting a site near Boston, off in the distance was some kind of radio transmission station. I was mostly fine with the EMI when my coil was flat to the ground, but when I put my machine down to dig a target and the coil front was tipped up slightly I could dang near hear Lady Gaga in my headphones. Even my X probe if I pointed it at the station would pick this up.

EMI in the soil, yes of course but this is going to be 60 cycle power line EMI most often from underground power cables, though if you are detecting in the area of overhead power lines it can come from above. Noise cancel doesn't help too much 60 cycle EMI, I crank back the sensitivity in those situations. Wireless dog fences are another example if buried in the ground of from below EMI. But agree with you fully any EMI that may be present in the ground, good practice doing your noise cancel with the coil on the ground. :thumbup:
 
sgoss66 said:
I feel that the FE number is MUCH more useful on the Explorer, than the E-Trac. On the Explorer, how the FE number varies tells you a lot about target type, depth, etc. BUT, look at what they did to the FE number on the E-Trac...they tried to "normalize" everything on the FE side to "12".Steve

Hence my hatred of the eDud and why I kick its ass on a routine basis with my Se Pro, Minelab went full retard on that change, don't get me started. LOL
 
I wish I still had my CTX or my Sovereign, I could easily tell you guys what frequencies BBS and FBS uses. I have a VLF spectrum analyzer here as part of my ham radio calibration and test equipment, but unfortunately I didn't have that back when I had my BBS/FBS detectors.

I just measured my V3i and was surprised to find that 22/5 kHz was the cleanest signal with the fewest harmonics, 7.5 next cleanest with a couple harmonics, and 2.5 kHz had by far the most harmonics. No wonder some V3i guys say that 7.5 is the best overall frequency for coinshooting, it is putting out the cleanest signal yet at a decently low frequency for high conductors.

Now I really can't wait to get my Equinox and see exactly what frequencies it is putting out. I preordered one last week and am supposedly one of the first in line in Idaho (behind Brandon of course!).
 
Charles (Upstate NY) said:
sgoss66 said:
I feel that the FE number is MUCH more useful on the Explorer, than the E-Trac. On the Explorer, how the FE number varies tells you a lot about target type, depth, etc. BUT, look at what they did to the FE number on the E-Trac...they tried to "normalize" everything on the FE side to "12".Steve

Hence my hatred of the eDud and why I kick its ass on a routine basis with my Se Pro, Minelab went full retard on that change, don't get me started. LOL

LOL! I can't say I disagree with you... :)

But, like I said, if they really could compensate PERFECTLY for ground minerals (which is likely impossible), then I could see where having an FE number would not be all that necessary, right? I mean, as I see it, FBS is "good" at -- better than any other VLF platform I am aware of -- at separating mineralized ground contamination out of and away from "conductive target ID info." And then, what relatively small amount of ground mineralization DOES "bleed through," they do a good job of keeping it pretty much confined to the "FE" side of things, not affecting the CO number much. Now, if they could make it PERFECT, such that they compensate for ground nearly perfectly such that NO ground mineralization information "bled into" target ID, then perhaps, maybe, it would work to eliminate the FE number, and just give us a single, "pure" CO value. I just don't know. Maybe they think that's where they are at, with the Equinox? That it copes with bad ground SO well, that they've managed with this platform to separate target from ground SO WELL, that they don't NEED to display target info in a 2D, FE/CO manner?

Steve
 
I don't want to veer too far off topic of the FBS frequencies, but here is an example of how I can use my spectrum analyzer to determine frequencies, and what the output looks like. This is what I just looked at for my V3i in 2.5, 7.5, 22.5, and 3-freq. The harmonics don't seem to affect the output signal strength, they all are about -60 dBm on the fundamental frequency, regardless of the harmonics. However, you can clearly see that in 3-frequency mode, each of the three fundamental frequencies are down in strength to -65 dBm to -70 dBm, confirming that multi-freq mode "spreads" the output power among the three frequencies.

The V3i is probably the closest to how the Equinox operates, so it should be easy to do a similar measurement of the Equinox when the time comes.

[attachment 350350 V3ispectrum2.5.JPG]
[attachment 350351 V3ispectrum7.5.JPG]
[attachment 350352 V3ispectrum22.5.JPG]
[attachment 350353 V3ispectrum3-freq.JPG]
 
Looking at my results with the V3i, it dawned on me that these aren't harmonics at all, but most likely just the results of taking the 22.5 kHz frequency and dividing it to obtain the desired "other" frequencies and suppressing, but not entirely eliminating, the undesired freqs with filters. It seems the V3i operates primarily at 22.5 kHz and 7.5 and 2.5 are simply the result of dividing, For example, 22.5/3=7.5, which also includes a 15 kHz signal which is suppressed. And the 2.5 kHz freq is simply 22.5 divided by 9 with the intermediate freqs suppressed. Very interesting!

So using this technique, it would be easy to determine the transmitting frequencies of the Equinox or FBS machines. However, we still wouldn't know how the received frequencies are being digitally processed. Some transmitted frequencies could be ignored, like with the V3i. But it would still be very revealing to at least know which exact frequencies FBS machines were being transmitted on. I may try to borrow a CTX or etrac and conduct the same measurements.

Or maybe somebody with a CTX could borrow an RF spectrum analyzer and run this measurement, which would also answer the OP's question.
 
sgoss66 said:
then I could see where having an FE number would not be all that necessary, right? Steve

I don't use the numeric display on my SE Pro, its the display of fail. Hats off to Minelab the SE Pro feeds your brain a LOT of target information. But the information is too complex and coming at you too fast to process with the numeric display imo, for that your brain needs the Smartfind screen in all metal.

Complexity...target orientation and co-location of targets with trash, nails, rotted iron remnants and mineralization. Fortunately the greatest discrimination circuit ever created is available, your human brain. Able to simultaneously process multiple targets, the cursor locations and bounce patterns, in unison with tone ID, target shape and depth in the tones as you sweep. Take away the Smartfind screen and I'm half blind.

The FE axis of the Smartfind screen is important to me for hunting gold. Probably the most variable target out there, 9k, 10k, 14k, 18k, white gold, yellow gold, comes in all shapes and sizes. FE can also be important for hunting silver coins, you ever dig a silver coin way over near rusty nail area close (but not in) the top left corner of the screen? They are there, also buttons up in that top/left corner area. Without FE all I have is conductivity to go on. Bobby pins way over in the bottom left corner of the screen but you can find some interesting jewelry and relics over there, again not buried right in the corner, but to the right of that.

Wait, I'm back to why I hate the eTrac lol.
 
Sgoss66 I think you are on the right track as far as the price point...what if the price was say around the $1700 mark would this make it a high end machine then...? ..or would they just fill better about there $2500 machine ...how dare they sell a better machine then mine for $900... Or even equal to it...
 
Very interesting stuff, Wayfarer. Will be interesting to see what your analyzer shows on an FBS machine, and on the Equinox. Like you said, this tells us nothing about how these signals are being processed, but it does reveal some interesting stuff about the transmit frequencies...

What's the unit on the x-axis? Milliseconds?

Steve
 
I hear you, Charles, on your preference for the smartfind screen. Me, I've always been a "numbers" guy -- my brain seems to like numbers and always has, and so when I started using the Explorer, I started on the digital screen and just never left it. But my point of view on that has always been that both methods, digital or smartfind, show the same thing (since pixels on the smartfind screen have a one-to-one correlation to number pairs on the digital screen). While you look for cursor positions, and patterns in the jumping/movement/fluttering of the cursor on the smartfind screen, I look for numerical values, and jumping/movement/fluttering on the digital screen. The patterns are revealed in both, it's just a matter of which way your brain can visualize best, I think.

So, along those lines, I think my point still stands. Here's what I mean.

It is my belief, based on experience using FBS, that the "magic" inherent in that platform is that instead of having target ferrous or non-ferrous information, and ground mineralization effects, all "wrapped into one receive signal from a single-frequency transmission," (which then needs to be "unwrapped" and broken into pieces as best as possible by the single-frequency machine's software), Minelab has found a way using FBS to "figure out" ferrous/non-ferrous information kind of "on the side," and then just feeding non-ferrous (let's call it conductive) target information (received as a result of multiple frequency EM wave transmissions), back to the user via the screen. And the only reason that we can't get a PERFECT conductive ID for a given target, is because soil mineralization messes with things, and some of the received "soil signal" (which includes both ferrous and conductive type signals) simply can't be stopped from "bleeding into" the algorithm outputting target ID numbers, ESPECIALLY on the FE side, and thus giving us the deterioration of ID number with depth that is common to ALL VLF frequency domain machines. It's just that FBS does a MUCH better job of keeping that contamination OUT of the target ID CO number as compared to other machines, especially on deep targets.

Now, this may not be exactly correct, technically, but it's what I've come up with after years of seeing how an Explorer "behaves," combined with some basic understanding of how metal detectors work. So, what I'm saying is, IF Minelab were to somehow succeed at accounting for ground mineralization in a even more accurate way, they could theoretically pull a large majority of, if not nearly all, ground effects OUT OF the target return signal, such that the return signal was nearly PURE TARGET INFO. And in that case, I could then see a lack of importance in having both FE and CO numbers, but instead just displaying a pure, uncontaminated-by-ground-mineralization conductive ID number...no need for FE/CO, no need for 2D smartfind screen, because there is nothing in the ID but nearly PURE conductive target characteristic info.

Obviously, this is easier said than done, easier to calculate mathematically in a lab than to accomplish in a real-world setting, but theoretically, I guess I could conceive of some future detecting platform being SO GOOD at separating ground info from target info, that the "2D" idea becomes superfluous and unnecessary. Is the Equinox representative of some "breakthrough" in this regard? Doubtful, but that seems to be some of what's being claimed by Minelab that they have, in fact, accomplished (at least in a more accurate way than before)...

Steve
 
Many of us use tone as a deciding factor and we love our smart screens which can give a good deal of information quick as you learn what your targets tend to do at depth. There comes a point where its all FERR thou and the machine can only say theres something there. The CTX has really improved TID, doing away with the smart screen to me is a step backward. Its what i liked over the whites single digit screen. none the less, id live with those digits why........ because like the CTX that screen is covered most of the time out there waist to neck deep in the water. As far as the price........is just that tech has made these components cheaper and more accessible?

Dew
 
What is it you really want from this machine?

OK I'm in the UK and we are fortunate enough to be in the position to be able to dig nearly everything due to the amount of history. I can't discrim out things like ring pulls as I would lose small hammered silver coins.

I am amazed at the amount of videos with screens blacked out with discrimination only to here the operator still say things like "it doesn't sound right or the numbers are jumping"

It is not a magic wand, and to get back to my original question, how are you going to manage with something that appears to be a technological step forward, but ultimately a beep and dig set up?
 
sgoss66 said:
Me, I've always been a "numbers" guy -- my brain seems to like numbers and always has, and so when I started using the Explorer, I started on the digital screen and just never left it. Steve

I'll reprogram your Explorer for depth, then you will switch to the Smartfind screen. :biggrin:
 
GazinUK said:
What is it you really want from this machine?

OK I'm in the UK and we are fortunate enough to be in the position to be able to dig nearly everything due to the amount of history. I can't discrim out things like ring pulls as I would lose small hammered silver coins.

I am amazed at the amount of videos with screens blacked out with discrimination only to here the operator still say things like "it doesn't sound right or the numbers are jumping"

It is not a magic wand, and to get back to my original question, how are you going to manage with something that appears to be a technological step forward, but ultimately a beep and dig set up?

Excellent question!
I think what matters is what is the operator's application ? Me, I'm a relic hunter. I want a fast multi freq unit that separates ferrous front non ferrous. That's it. I dig all non ferrous targets. Numbers are just a loose guide. I could care less about hunting in a park trying to discriminate a pull tab from a gold ear ring. So, I guess it is all in the application as to what a guy wants from a machine. Like you, I never understood why some guys load up on the discrimination and expect the machine to run well.

Dean
 
sgoss66 said:
Reprogram it for depth? Sounds good to me... :)

Can I at least "peek" at the numbers sometimes? :)

Steve

The numeric display is fine up to a certain point, a bit further for someone like you experienced watching bouncing numbers. Beyond that, in that zone near and to the machines absolute limits I don't see how anyone could use the numeric display. At the machine's limits where you may not even get an ID but every 3rd swing and a tone every 2nd swing, and when you do the ID is in no mans land far from known coin areas and jumping around, mixed with jumps to iron, bobby pins, its all over the place. At its limits you know there's something down there but you know not what. Its going to be a best guess ferrous/non-ferrous over multiple swings watching how the cursor behaves.

So just how bad will this signal be? In another thread we have been discussing coil balance, here at the machine's limits you are talking about a target that just barely upsets the coils balance. This is why its good to know how coils are built and something about coil balance. So when something upsets this balance you know the why behind what's going on. These signals are so slight they resemble a whisper that's been reduced by 75%. They are not even as strong as noise or chatter, faint in volume, short in width, a soft pillow of almost nothing. All you really know is something is upsetting the balance of the coil every so slightly and that it repeats in the same spot. It may not repeat every swing but if its repeating every 2nd or 3rd swing its a target. That's the machine at its limits.

I spent years hunting inland and I would never dig such a signal or even be looking for one. Then I spent several years hunting beaches. Its so fast and easy to dig targets in wet beach sand with a scoop that you will dig almost anything. That targets can be very deep or very small on a beach, and potentially silver or gold is another reason why you might dig them. What I found was its a great way to learn just what the limits of the machine are. I long ago lost count of the number of astonished expressions I had after digging some nothing of a signal.

Where does a huge Spanish 8 reale silver coin ID, over with silver dollars right. Would it surprise you to hear I have dug them with the above nothing type signals that ID just above nickel, and that was only on the swings where I got an ID at all.

Don't abandon the numeric screen for most of your hunting, you know it, your brain is trained on it. Instead dedicate 30 minutes of your hunt to the above type of signals, its one of those things you just have to prove to yourself in the field. Spend 30 minutes looking for and digging the above type of signals then report back. :thumbup:
 
I think what matters is what is the operator's application ?
and then
I never understood why some guys load up on the discrimination and expect the machine to run well.

You answered your own question LOL.

Personally I run my E-Trac, most of the time, with a very aggressive discrimination pattern. Fact is I do quite well actually.

This pattern would scare the hell out of most people, but have you ever hunted and old bar parking lot or Drive In theater?

Right pattern for the right job.

tightcoin.jpg
 
sgoss66 said:
Very interesting stuff, Wayfarer. Will be interesting to see what your analyzer shows on an FBS machine, and on the Equinox. Like you said, this tells us nothing about how these signals are being processed, but it does reveal some interesting stuff about the transmit frequencies...

What's the unit on the x-axis? Milliseconds?

Steve

X-axis is frequency in kHz. The 5, 10, 15, etc. across the bottom is the frequency that the detector is operating at.

Y-axis is signal strength. The jagged line that goes all the way across the bottom at about -110 dBm is just the natural background noise, or "static." The vertical spikes are the actual measured real-time transmit frequencies of the detector.

I'm trying to borrow a CTX to measure it, I've got the word out, so maybe sometime this week, I hope, I'll have some results for the FBS output frequencies.
 
There's a very informative thread on another forum regarding this. the conclusion they reach is "It uses alternate bursts of 1 cycle of 3.125kHz then 8 cycles of 25kHz". The 28 frequencies is a marketing claim. Only those two frequencies are actually processed.
 
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