VLF vs. PI vs. BFO

[findstuf]

VLF vs. PI vs. BFO...

Are one of these detector types head and shoulders above the others? Is there a detector out there that combos two of these into one machine? I've noticed some have the pinpointers attached to vlfs. Is that basically a homemade combo machine. I'm just getting back into MD'ing so bare with me..

 

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[Carl-NC]

BFO... dead.

PI... goes deepest, best for salt beach hunting and highly mineralized nugget hunting, little/no discrimination.

VLF... best for all-around everything else.

Inline pinpointers are just a coil, you use a switch box to switch between the regular coil and the pinpointer.

- Carl

 

[Joe(TX)]

............findstuf..............you may have been referring to the VLF/TR's..........this detector had 2 different modes...........one was a VLF.........Very Low Frequency which was an All-Metal Mode......no discrimination but could Ground Balance.................the other mode was TR....Tranmitter Receiver.....which was the Discrimination Mode.......Also depending on the brand there was either a toggle switch or a push button switch where one could switch back and forth from each mode and tell alot about the target/signal before even digging it up!!......................Also you may have seen on Ebay some auctions featuring the Vintage Bounty Hunter Outlaw.................This was a TR/BFO combination detector.............unique at the time when it was new......but really outdated today.....the TR and BFO was on the higher frequency of the older machines and could not ground balance........5 inches on a quarter was accepted as GOOD................most detectors today could pick up the same quarter at about 10 to 12 inches!!....................HH.............Joe

 

[findstuf]

Thanks guys,

I did some searching after I posted the original thread. I was trying to figure out why you would want a pinpointer. My MD is a fisher cz-7, it has a pinpoint feature, i can switch between "wide open" and an "identification" mode. After watching the garret video on it's pinpointer, I think I got it. A pinpointer can speed up your find by a minute or two.

Generally speaking, are all pinpointers the same? meaning are they all VLF or PI or BFO.

 

[Carl-NC]

"Generally speaking, are all pinpointers the same? meaning are they all VLF or PI or BFO. "

If you are talking about separate hand held pinpointers, some are PI, some are VLF, and at least one is off-resonance, a variation of BFO. Pinpointers are very helpful in the recovery process.

- Carl

 

[findstuf]

Thanks Carl,

You got my gist. This thread is kind of all over the place, but I got my original question answered then I changed the subject to pinpointers.

Now a specific question. What the heck is a FZ-1 pinpointer? Does it just piggyback into the factory connections and detours to the handheld pinpointer, or is it a totally separate electronic box in-line with the factory connections? It looks cool and convenient, I hate carry extra junk in my pockets.

 

[Carl-NC]

Thanks Carl,

You got my gist. This thread is kind of all over the place, but I got my original question answered then I changed the subject to pinpointers.

Now a specific question. What the heck is a FZ-1 pinpointer? Does it just piggyback into the factory connections and detours to the handheld pinpointer, or is it a totally separate electronic box in-line with the factory connections? It looks cool and convenient, I hate carry extra junk in my pockets.

Sunray makes in-line probes for a bunch of detectors, the FZ-1 sounds like their probe for the Fisher CZ series. Typically, it will have a switch box that you plug the probe and the coil into, then manually switch between the two.

- Carl

 

[findstuf]

question on the PI detectors.. Say you are a person who has enough patience to dig every signal, would a PI be the best choice? Are most PIs detectors designed for underwater? and would an older model PI work as well and a newer whizzbang PI?

 

[lamar]

Dear findstuf;
You asked a good question:

"question on the PI detectors.. Say you are a person who has enough patience to dig every signal, would a PI be the best choice? Are most PIs detectors designed for underwater? and would an older model PI work as well and a newer whizzbang PI?"

I have a Minelab GP-3000, a Minelab SD-2100 and a White's GMT-E. Both of the Minelabs are PI detectors and the White's is a VLF. Whether or not a person is willing to dig every signal is wholly dependent on the conditions the detector is working in. In remote areas with little or no trash a PI detector is the ONLY way to go! In a park a person would have to be completely nuts to use a PI detector. A PI detector is good for finding gold and silver nuggets, old relics, old sites, etc. They are so sensitive that I've detected pottery bits, colored glass and even old campfires, to say nothing of the multitude of pull tabs, beer cans, bullet slugs, horse shoes, etc. A PI will detect EVERYTHING!

If I am hunting for nuggets in a trashy area I'll go in first with my GMT and clean out the area of all trash then go back in with either my SD-2100 or GP-3000 and clean up the nuggets! The good thing about *most* trash is that it's on the surface or immediate subsurface so a lot of digging isn't really necessary. Of course there are always those horse shoes that somehow end up 2 feet underground and an hour or so is wasted recovering it. But then again, you always get the pleasure of seeing just far you can heave it too, so it's not all bad. And those types of targets are fairly rare, so it's all good.

Most PI detectors are designed as dry units, that is to say they are not waterproof and they are not even water resistent. Garrett makes an underwater PI if I am not mistaken but I've never used it so I don't know if it is a good detector or not. AFAIK Minelab does not build an underwater PI detector.

I have the old SD-2100 and the newer GP-3000. The SD-2100 cost me 1200$ new and the GP-3K cost me 3,200$ new. The newest Minelab PI is the GPX-4500 or something like that. It sells for around 4,500$ if I am not mistaken. If I were offered any one of these three detectors, BUT I could only choose ONE of them, my hands down choice would be the SD-2100. I know this seems strange and illogical, however the SD-2100 is a VERY sensitive machine and it is bare-bones simple to set up and operate. With a round mono coil on my SD-2100 I'd say that it is every bit as sensitive to larger, deeper targets as opposed to my GP-3K and I wouldn't be afraid to put it up against the new GPX-4500.

When I first started using PI detectors I used mostly DD coils, but now that I've gained experience I've realized that round mono coils are the only real way to go. The mono coil is so much more sensitve than a DD coil on my SD-2100 or GP-3K. The GP-3K can detect those tiny nugs at shallow depth better than my SD-2100 is able to do, but then again, I am willing to walk over those tiny match head nugs in search for the larger, deeper nugs. Pulling those sub-gram nugs out of the ground is both time consuming and tedious and in the end it doesn't pay to recover them unless those are the only offerings in the area.

Also, Minelab has very recently stopped producing the venerable SD-2100 detector. They are continuing to produce the SD-2200 with automatic ground balance, but I am not impressed with the auto g/b found on the ML PI detectors, therefore I'll stick with my manual G/B SD-2100. If you have enough patience you can scout around and pick up a nice SD-2100 for under 800$. Just make sure that it is the newer blue box Version 2 SD-2100 and not the earlier green box model. The two detectors are virtually identical in performance and the only real difference between the two, besides the color, is the earlier SD-2100 does not have a balance knob, rather you must use a tiny flat bladed screwdriver in order to set the detector up. To me this presents a major hassle as it does for most detectorists.

Also, White's has introduced a PI machine which they call the TDI. I have not had the pleasure of using the new TDI yet, but the reviews from some very highly regarded nugget shooters have declared this new 1500$ White's detector to be a top-notch contender to the 4500$ Minelab GPX-4500. If I were in the market for a new PI detector then I would SERIOUSLY consider the TDI as a possible purchase choice. One highly regarded PI detectorist called Req has seemed to master the technique of using the TDI in city parks and searching for only gold and silver targets. Go here to read the comments on the TDI detector:
http://tdi.invisionplus.net/index.php?mforum=tdi&showforum=3
I hope this helps you.
Your friend;
LAMAR
Your friend;
LAMAR

 

[findstuf]

Great info, thanks for taking the time to post it.

 

[findstuf]

a few more PI questions.. how long have these been around? I found a reference on google that mentioned archeo-types have been using PI detectors since the 1960s. There obviously is a big price range on these, what is the typical low end? $800?.. there is no gold down here, but lots of old sites. My cz-7 maybe hits 12" when set on "auto". The "auto" setting is sorta like wide open, beep at anything.

 

[lamar]

Dear findstuf;
The depth of all detectors to include PI detectors is wholly dependent on the size of the target, the surface texture of the target, the composition of the target and the length of time the target has been lying in the ground. As an example of the depth a PI detector is able to achieve I recently recovered a .22 slug at beyond 19 inches in tightly compacted soil. I was using my GP-3000 with a Coiltek 18" round mono coil and the signal sounded SWEET! It was a nice clear tone and I was certain that it was either a gold or silver coin.
Your friend;
LAMAR

 

[Carl-NC]

Yes, PI detectors have been around since the 60's, mostly then as an archaeological tool. They started showing up in underwater detectors for treasure hunting in the early-mid 70's.

- Carl

 

[Real de Tayopa Tropical Tramp]

Evening Carl, thanks for taking the time for your input.

Don Jose de La Mancha

 

[findstuf]

Yes, PI detectors have been around since the 60's, mostly then as an archaeological tool. They started showing up in underwater detectors for treasure hunting in the early-mid 70's.

- Carl

If they have been around that long there should be a bunch out there. Do people usually hold onto the PIs forever?

So are the PIs more of a professional grade item?

 

[lamar]

Dear findstuf;
There are those people who have to have the latest & greatest PI because they think it gives them the edge, however most of it is just hype. You probably should bear in mind that practically ALL of the people who have Minelab PI dectector forums in the western part of the US are also Minelab dealers, therefore they they will study every possible setting on the newest model detector and then really pound an old patch to death with it, then show their crumbs on their respective forum and they proudly show the world how *sensitive* the newest mega-dollar Minelab detector is, when in truth, a skilled operator with an SD-2100 can locate those very same nugs with a detector which costs a third as much.

Pulse induction technology has changed very little since it's inception and because of this Minelab, and now White's are maximizing on the PI dectors' already great depth by enhancing the audio circuitry in the detectors. As a PI detecor's signal travel through the ground it picks all of the ground interference until it reaches a point of null return, meaning that a possible target can no longer be distinguished because it is blanketed by all of the background noise. Manufacturers are digitally processing the audio circuitry to smooth out and eliminate the background clutter, thus making the detector quieter andmaking the target signal audible.

This is also where the White's TDI detector shines forth, my friend. It is quieter than the Minelabs and thus a person can use a TDI around powerlines, aircraft flying overhead and it towns and cities, whereas a Minelab detector simply goes bonkers around these types of electromagnetic interference. This is another reason why I will buy a TDI detector for my next PI.
Your friend;
LAMAR

 

[findstuf]

thanks again.

 

[lamar]

Dear findstuf;
My pleasure, my friend. I have about 5 or 6 years behind the ML PI detectors now, I am more or less informed about how they function,l what their strong points vs. weak points are, etc. If you have any more questions in regards to the PI detectors, please post away! The questions which you ask now may save you HUNDREDS and possibly THOUSANDS of dollars!
Your friend;
LAMAR