Digalicious

When I first heard that Nokta was working on a new pinpointer, I thought for sure it would have a screen, be PI, and have a holster on / off switch of some sort. Well, I got 1 of 3 right! Then after finding out it was a 20 khz VLF, my next thought was, "20 khz might not give the greatest ground penetration in mild ground, but may in higher mineralized ground". Although of the few actual hunts I've seen with hunters testing it, not one complained about depth issues. So my theory may be totally wrong 🙂 I'd sure like to know why Nokta decided against the Accupoint being a PI, and why they chose 20 khz. Perhaps it has something to do with detector / pinpointer interference noise? But, frequency shifting seems to work very well to mitigate pinpointer interference. Everyone here knows that I think SMF frequency shifting on detectors is useless for EMI noise reduction. Reason being, the source of the noise is wideband, and so is the SMF receiver. But, noise reduction works great as long as either the source, or the receiver, is narrowband. In this regard, a pinpointer is narrowband, so frequency shifting is very effective.

I just realized that MFF said he has only been detecting for two years, and has 11 pinpointers. I think MFF just dethroned Simon 😁

I'm looking forward to that review F350. Weird about the box thing though.

Said "splitting hairs", coupled with misleading, and most often poor methodology, easily sways the newbies. The good thing for the manufacturers? Litte to no advertising cost.

It looks like great hunting grounds, and all things considered, that 2 cent piece is in great shape. Are you guys giving up on it, or going to give it another go?

On "paper", one could get just about anything to seem like a breakthrough. Get it into real world scenarios though, and the truth comes out.

I didn't watch the video, but I suspect it's similar to his "Bird Dog" program for the D2. He claimed the program would provide better iron unmasking. When he first mentioned that program on another forum, I told him that his test was interesting, but if he actually hunted with that program in iron infested ground, then it would probably result in massive iron falsing. Turns out, that is exactly what happened when experienced hunters tried the program.

Comedic gold from comedic geniuses.

EPIC!

That's a weird issue Mark, especially given that they pair to the Nox, and the Legend pairs to other headphones. This is a long shot, but try this: Power off the phones, then turn on your Legend. When the Legend starts searching for the phones, power up the phones.

That's why I joined this forum. I still participate in another forum, but not so much anymore. I rarely even read or post on the Facebook detecting pages anymore. The other forum mainly seems to be about finds. I wanted a forum that is mainly based in technical aspects of metal detectors, and when it comes to that, this forum delivers 🙂

I don't have any sites that are overgrown as the picture CPT posted, but if I did, I would make a full diameter coil cover. That way, all the foliage wouldn't get caught up in the coil ribs.

Trying 1.13 would make for an interesting test. Any word on that yet?

Thank you for the clarification Geotech. I wasn't sure "accumulating" was the term the engineer used, hence I started with, "went something like this". The EMI issue began for me with the use of two different SMF detectors, from two different companies. I soon discovered that it didn't matter if I was right near large capacity power towers, or in a local park...noise reduction never reduced the EMI noise at all. Further to that, in the countless videos I watched from various YT'ers with various SMF detectors, EMI noise reduction did nothing for them as well. I then asked on a couple of Facebook pages and forums, if anyone could post a short video showing the noise reduction on their SMF detector actually reducing the noise. Well, it was crickets all around. Around the same time, I discovered that SMF modes have a primary frequency. For example, the Legend's M1 primary frequency is around 15 khz. I would be in high EMI using M1 and the noise was intense, yet switching to the SF of 15 khz, caused most of the noise to disappear. That's when I realized that SMF is inherently more open to EMI than SF, despite SMF modes having a primary frequency. When I asked about that, an engineer either said it's because the frequencies and their associated EMI gets "accumulated", or he might have said "they get added together along with the EMI". I can't remember the exact term he used, but it was either "accumulated" or "added together". I'll try and find that post.

What the ad says: There's 2 red flags in that quote: 1) "Up to" is meaningless. In other words, up to, could mean only 1%. Companies use the up to term, in the hope that people focus on the high number, and not the "up to" part. 2) 30% on what? Certainly not a coin sized object in the ground, otherwise they would have stated so, instead of making a meaningless and misleading statement about its depth. Like I said previously, it's 30% more depth on objects much larger than coin size. Above around the 13" to 15" coil size, sensitivity to coin sized objects lying flat in the ground begins to significantly decrease. That decrease in sensitivity is even more pronounced when the coins aren't lying flat. The larger the coil, the more spread out the field's waves are, and the less eddy currents are produced, on equivalently sized targets. Going from a 15" to 18" coil, would likely provide no additional depth on coin sized objects in the ground, and may even get less depth on edged coins. Throw in the extra ground interference and extra EMI, and it gets even worse. Once coils get above that 13" to 15" range, it's about extra coverage, not extra depth on coin sized objects.

"Up to 30% more depth than the 15" coil". Ya, maybe 30% more depth in the air, on a target the size of can. Whenever a company uses the term "Up to", they are being deliberately misleading.

I guess it comes down to one's definition of a "good target". If a good target is considered to be a high conductor, then I would agree, because most EMI IDs randomly in the low to mid and mid high conductor range. If a comparative algorithm was utilized, then most of the EMI signatures / IDs (the random low and mid to mid high IDs) would be eliminated, along with very deep coins, most gold jewelry, and collocated coins. Countless metal detector engineers over the past few decades, have been trying to solve the EMI issue. I believe it's correct to assume that a comparative algorithm would have been one of the first things they all thought of, but then quickly dismissed it as unviable. I suspect they quickly concluded that a comparative algorithm would mean the proverbial, "Throwing the baby out with the bath water" 🙂

I completely understand your point. Each sample from each frequency should have different EMI signatures. Therefore, a comparative algorithm would be able to discern the EMI noise, from the ground signal and target signal. However, it seems to me that since most of the EMI noise has a "signature" identical to good targets, then the algorithm would often throw out the EMI signals, along with the wanted signals.

About a year ago, I read a post in which a metal detecting engineer was explaining why SMF is so much more suspectable to EMI than SF. It went something like this: With SMF, multiple samples (frequencies), get accumulated during the processing. Therefore, the EMI noise also gets accumulated accordingly. I think the bottom line, and most important aspect of EMI, is that a metal detector does not, and cannot, know if a signal is coming from the air, or coming from a target in the ground. As such, there is no true way of mitigating the EMI, without a performance loss in one way or another. For example: EMI signals are typically weak, and that of course, is why reducing the gain on the amp, mitigates the EMI, but that means depth loss. Switching to a SF that is outside the range of the EMI is another option, but then the benefits of SMF are gone. The difference in the channel frequencies is very small. Something on the order of a mere 0.02 khz difference between the channels. That's just too small of a shift to mitigate the various frequencies, harmonics, and random nature of EMI. Further to that, a frequency shift doesn't address the fundamental problem of noise when using SMF. That is, the exponential rise in noise due to SMF accumulating the EMI noise.

Might as well. You've already got the saucer section of the Enterprise! 🙂

I'm just as surprised by the way the coil mounts, as I am that Garrett makes available the old White's manuals. By Garrett doing so, is a respectful "tip of the hat" to Whites 🙂

Thanks for that Jim 🙂 I really enjoy checking out the vintage detectors, but I've never seen a coil mounted like that. Not even in the Whites vintage brochures.

Uhhh.... Where is the shaft connector, and what the heck is that antenna looking thingy?

Good point about the audio response. Emi gives a tone and ID, but for the most part, it produces weak signals. Which of course is why reducing the sensitivity cuts out the emi noise, and why the audio response would cause the emi noise to be louder. Emi typically ID's between ferrous and zinc, so ya, cherry picking for high conductors discriminates out most emi.

I'm going to elaborate on that. I learned to live with it because: 1) I'm not willing to significantly reduce the sensitivity and its associated depth loss, just because of noise when the coil isn't on the ground. 2) I'm not willing to switch to SF unless I absolutely have to. Reason being, I find SMF's target ID accuracy to be notably superior to SF.