Digalicious

That was extremely thorough. Thank you 🙂

Good point and nice job kac! I've never heard of liquid electrical tape, but oh ya! I'm ordering some now 🙂

Thank you for the replies so far. It's interesting to hear that those 30 year old detectors are still running strong. More specifically, the capacitors haven't burst and leaked onto the board.

Hello. What kind of time frame are we looking at before component degradation causes performance issues, and what kind of issues would they be? Sensitivity loss? Choppy audio? I guess it would be hard to give a time frame due to many conditions, but I would think the old analog detectors have a lot more components such as resistors and capacitors that could degrade, compared to more chip based digital detectors.

With detector tests, there almost always has to be a margin of error. For this particular test, I'd say that margin of error is about 1/2". However, that margin of error is too small to change the relevance of the results. I wasn't surprised by the results of the sensitivity tests. Although in my recovery test, I was really surprised to see no notable depth difference between 1 and 5. Depth difference only occurred once I started to go above 5.

I normally don't assume much of anything either. However, the target characteristics and frequencies have no bearing on the percentage of depth loss when reducing the receivers gain.

Hi Jeff. I made it a point to be as consistent as possible as you described. Regardless, both our test results are similar enough to arrive at a similar conclusion. Curious though. Why bother with different frequency modes and types of targets, because neither of which should be relevant with this type of test. ...unless I'm missing the obvious?

You're welcome. There is one site I have that has giant high voltage "power towers". The only way I'm able to use my Vanquish 540 or Legend there, is to significantly drop the sensitivity. On the Legend, the EMi wasn't mitigated until I lowered the sensitivity to about 20. 4 khz and 10 khz were still noisy. It wasn't until 15 khz before the EMI really quieted down. I chose to use 15 khz with max sensitivity instead of SMF with 20 on the sensitivity and a 3" depth loss.

Hi oldcoinhunter. Dropping the sensitivity level in any frequency mode, will produce the same depth percentage loss 🙂

Hello. I did an air test to give me an idea of how much depth is lost when the sensitivity has to be reduced due to EMI or other factors. Although depending on the ground conditions, a SF can be used to mitigate EMI. I used the 6” coil, a silver dime, M3, and the default of 5 for the recovery speed. 30-10” 29-9.5” 28-9.5” 27-9.5” 26-9” 25-9” 24-9” 23-8.5” 22-8” 21-7.5” 20-7” 19-7” 18-6.5” 17=6.5” 16-6”

I don't get that level 9 either Herr. Sheesh, level 8 already means a lot of missed good targets in ferrous trash. If I were on a site that's driving me crazy because of shotgun shells, I certainly wouldn't raise my IB. I would notch them out. Then again, what type of shotgun shells is Nokta referring to? I don't know much about shotgun shells, but a quick Google search says they can be made of both ferrous and nonferrous metal.

JCR, Thanks. I was really surprised to see no depth difference between 1 and 5. But, I was just as surprised to find that no matter what the recovery speed, the slower I moved the dime, the less depth I got. The ground is frozen solid here, but I'm going to see what I can do to accomplish an in ground test and make a video about it. Tucannon, Hello. I was indoors and at 22 for the sensitivity. I'll edit my original post to include that 🙂

Thanks for that Chase. I've decided that come spring, I'm going to ignore all coin signals. I'll only be hunting for gold jewelry, and cool / unique relics. As such, on each site, I'll deeply bury a small gold ring, and see what frequency(s) hit it best. It's either going to be M2 or a SF of 15 khz or higher. My concern with this approach is missing silver rings with diamonds. Perhaps I'll just ignore 40-48 to ignore the pennies and dimes, or perhaps just ignore 46-48. What do you think of that?

I'm a computer technician, so I "hear" ya 🙂

So I'm not the only one nerdy enough to use an ellipse and concentric, surface area calculator 😁

I just tested the ID and tone with a pull tab touching a dime. The pulltab alone is a 30 ID and the dime is 46. I tried recovery 1, 5, and 10. With 1, 5, and 10 on the recovery speed, and on M1, M2, and M3, I could get a solid tone with an ID of around 36. So, I would have dug on all three of those recovery speeds. Thing is though, with a 4" depth loss between 5 and 10 on the recovery speed, I'm thinking of keeping my recovery speed at the default of 5, no matter how trashy the site is. Another eye opener? With the same test at 4 khz, the ID was 46! I've been thinking about this for a while, but it looks like from now on, I'm only going to use single frequencies (granted I don't have highly mineralized or salt ground).

I air tested with the 6" coil and a silver dime. I was indoors and using 22 for the sensitivity. RS=Recovery Speed, DF=Depth on Flat dime, DE=Depth with the dime on Edge. RS / DF / DE 1 / 10" / 8" 2 / 10" / 8" 3 / 10" / 8" 4 / 10" / 8" 5 / 10" / 8" (default recovery speed) 6 / 9" / 7" 7 / 9" / 7" 8 / 8" / 6" 9 / 7" / 5" 10 / 6" / 4" So not only did I find no depth difference from 1 to the default of 5, but with all recovery speeds, the faster I moved the dime, the better it was detected.

Hi Chase. I don't know if this matters much, but when I had a Simplex, I compared the 11" round DD coil with the 9.5x5 coil, and in my test bed, I'd say I only lost about 1" on coins lying flat, and no apparent depth loss on small targets such as coins on edge. My guess as to the latter, is that the 9.5x5 coil has a "tighter" field that makes it more sensitive to small targets compared to the round 11". Other things to consider of course with the smaller coil, is that it's much lighter, has better separation and unmasking abilities, and is less susceptible to emi and ground noise (so sensitivity can be increased higher than the 11"). I could be wrong, but I'm thinking that once a coil gets larger than about 11", then the depth advantage diminishes very quickly on coin size and smaller targets.

***Flame suit engaged*** I propose that all SMF detectors since the Nox and forward, will hit the same targets with the same settings. Or, very similar.

It seems Nokta found a way to get the coil weight down. For example, the LG24 has significantly more surface area than the LG 15, yet they weigh the same. Due to winter, I can't hunt for about the next 3 months, but I still want the LG24 now! lol ...first world problems 😁

Also Herr, it might be helpful for you to keep in mind that depth meters are actually signal strength meters. Meaning for example, that a deep coin lying flat will max out the signal strength meter, but so will a much more shallow BB sized target.

Agreed. 4 khz is still the best at ID'ing nonferrous targets in nonferrous trash, but M3 is pretty close, and both are notably better than M1. The main disadvantage of SF, is the inability to use an adjustable iron bias. However, it's my understanding that SF modes inherently have a low iron bias. It's yet another thing I'll be testing out in my winter off time. All I can do in the winter is performs tests, and incessantly yap about detecting 🙂 On a side note, when the testers were testing the new M3 a few months ago, some found it's weighting to be identical to the MW weighting, but still not quite as good as 4 khz. I and one other tester of that M3 that I'm aware of, requested that the new M3 be weighted even more toward 4 khz. I don't know if that suggestion was implemented, or if the suggestion was even possible. I mean, it's already heavily weighted toward 4, so I'm not sure the engineers could have weighted it even more, before they declared, "Any more weighting toward 4 khz, and you might as well just use 4 khz!" 😁

Perhaps akin to a Steve Wozniak needing a Steve Jobs?

Here's a 3 minute video from "History Revisited", showing the Legend easily hitting a coin that is directly under the head of an ancient, large, and corroded nail. Note that he's using the correct settings for iron unmasking. I.E: a low iron bias, high weighted SMF mode, and mid / high recovery speed.

I think you're right D. That is, GS is a filter for unusually high mineralized ground.