jasong

Hmm, oh well. I was getting excited reading the reports about stability increasing. Good to know ML is doing updates though, bringing detectors into the modern age, opens up the door for interesting updates in the future like new timings and whatnot that could be real interesting.

Anyone had the new update out and on the ground yet? I can't get into the field for a while yet to try it out but I'm very curious if it's stopped some of the hehawing on salt, takes care of clay lenses better, runs smoother over rough ground, etc...? Or any noticable change in stability? I read on the Aussie forums that people are reporting being able to bump their thresholds up now. Any reports?

AUAddicted, do you have the new Nokta waterproof pinpointer that is like the Garrett Carrot or the older one? I have the newer one and I haven't noticed any interference issues when its off (definitely does when it's on and too close to coil) but maybe I've just had it far enough away all the time, not sure.

Sample bags are in my pack too. The ziplocks with the white bar across them for labeling work pretty decently for cheap ones. Something that not everyone has a use for but if anyone likes making prospecting videos, I bought one of those $3 Amazon cell phone tripods with all the adjustable balls and it's the best $3 I ever spent, that thing packs away easy and is so much easier for shooting videos than trying to hold the phone with 1 hand and dig with the other.

Nice, can't wait to get out to the field and try this out.

Or sell it! Any more than a few nuggets with special memories always seemed superfluous to me. Compared to the things I've bought and been able to do with the money I made off my gold, I have never once regretted getting rid of some small, shiny yellow rocks that I rarely even look at (especially when they are in a safety deposit box). I feel bad for that guy though, so much hard work, at least the memories are still there but that's hard...

Thinking battery voltage = more powerful machine is wrong on quite a few different levels, some require a decent knowledge of electronics to understand, but here are a few of the more basic ones: The internal electronics themselves step up or down the voltage as needed. The pulses on PI machines are often in the hundreds of volts despite having low voltage battery sources. Its far more complex - and just wrong - to related the "power" of a detector to it's battery source voltage because those voltages are usually changed anyways inside the machine. Again, the ML pulse machines are using 7.4v batteries, which is on the low end of the detector spectrum yet they are undoubtably the most powerful detectors on the market. Also, in VLF's, the coil doesn't see a DC voltage at all, the battery power is used to do things like drive voltage controlled oscillators that create oscillating waveforms - aka VLF frequencies. The PP voltage of those waveforms need not have a direct relation to the source battery voltage and are usually completely different than the battery voltage anyways. All this aside, P = I*V (you are ignoring the I part) and AA and 9v batteries are current limited by their internal resistances to fairly small values anyways. So the previous two points aside, it's common to have batteries of higher voltages that have less overall power capacity. I haven't done the calculations but I bet you'd find a 9v battery only has about as much energy as maybe two 1.5v batteries. Also consider different chemical makeups, a 1.5v Nicad has far less energy than a 1.5v LiPo despite being the same voltage. Or, think about a static shock, its probably tens or hundreds of thousands of volts but the amount of current is negligible and the total power dissapation is also negligible. Anyways, it's a Nokta thread on their new machine, not a thread on battery voltage so I won't comment any further on this. Just wanted to point out that this is not a valid criticism for any detector, be it a Nokta VLF or ML PI machine. The main thing to discern from source batteries is how much capacity they have and how efficiently the machine uses that capacity (aka battery life). And as mentioned already it seems like the Gold and the Core are using it pretty efficiently.

There is no relation to battery voltage and detector power. The big Minelab batteries are only 7.4v. Also I agree, my Fors Core gets great battery life. Hey Dilek, reading another thread about an armband makes me remember something I was going to mention with the Fors Core that I wonder might also apply to the Fors Gold +? The armstrap is too small to fit around my bare arm and the armrest is just barely large enough for me to put my arm in, and I'm not exactly burly. It'd be good to make the straps another 2 inches longer or so and widen the armrest out a bit if that would be possible.

Hmm that'd be cool, I've been waiting to see if they'd do firmware updates, sure seems like that is what the machine is designed for. Firmware updates leave open the possibility that I brought up before the GPZ was released that future models (8000, 9000, etc) can be entirely software-based in theory and thus much cheaper for those who already own the hardware. It will be interesting to see if this rumor has any meat to it, makes the machine far more versatile if so. Next stop: custom timings. Just like the app store on your phone, buy a specialized timing for $2.99 and let customers make/sell them, imagine that, not going to happen for obvious reasons but interesting to think about for detecting future.

IMO Smoothing Off is more like a Stabilizer setting of ~12-14. I can't detect most places with the stab at 20, but I can detect most places with Smoothing off if I'm feeling patient (barring storms, salty ground, and right next to cities). I think the Sens/Gain is close but not equal. To me changing the Sens makes more difference than changing the Gain, especially at higher levels. Also, (especially with the 4500 but also with the 5000), upping the gain at higher levels seems to only increase EMI and not actual depth or sensitivity to small targets. Upping the Sensitivity on the GPZ at high levels seems to keep increasing the depth and sensitivity to small targets in a way that doesn't happen on the GPX. Also, I can't help but feel that 14-15 on the 4500 and 18-20 on the 5000 just make it noisier, but I find 18-20 on the GPZ to be actual useful settings. It's almost like GPX gain is logarithmic (think ln(x)) and the GPZ sensitivity is linear (think x) to me when looking at depth/target sensitivity, and both are linear when looking at noise.

I agree, good post and it's something you very rarely see. I've had good experiences with all the BLM geologists I've worked with so far both in permitting (NOIs) and general discussion. I hear that in less mining friendly parts of the country this may not be the case, but there are definitely geologists out there who want to see us succeed as small scale miners and I cringe when I see people assuming the good ones are out to get them. I also had good experiences with the GIS and LR2000 guys out of Denver and the guy from USGS who (used to?) manage the MRDS database among other jobs. Also agree that going in having done your research and with a good attitude goes miles, because a lot of times these guys are on our side (some are even prospectors themselves) but can end up getting alienated by angry people.

Hey Wes, on a side note, don't know if you got your shaft yet but I just got a replacement shaft for my GPZ delivered an hour ago, they covered it under warranty. I think I had a similar problem to yours, mine rotated a lot and then the plastic key broke off. Anyways, might give them a call and remind them if you are still waiting for yours because they definitely have them in stock now.

I've never been able to replicate any kind of performance gain outside a normal margin of error for any of the new Coiltek or NF coils I've bought since my older fiberglass models that I bought used when I started detecting for gold. The biggest difference I see is between potted and unpotted coils, the unpotted go bad much easier. Maybe the added weight of the new models is just a ton of epoxy resin...no idea. It'd be nice to at least have some kind of basic idea though before outlying $400+ My personal suspicion is that a lot of performance gain is just due to confirmation bias. But this new generation is the first where something is definitely physically different - different geometries and more weight, so I want to test it out, still looking for people who would like to participate. Also one thing on comparing coils directly, they should be used on the same machine with the same settings, and if compared to a different coil the area of the coils should be as similar as possible. Since the pulse power is staying the same then the flux density across the coil will change if the coil size varies, and thus the sensitivity will change.

Hey MXT Sniper, are you in Arizona by any chance? Would you want to meet up to do some testing with your Elite along with my NF Evolution when I get it? Minelab had a bunch of patents I read, then released a bunch of Whitepapers, and also released fairly extensive results of depth testing on a large number of different types of gold. Also some vids with their engineers explaining timings. I don't understand the GPZ exactly, but I do understand it enough to know it makes sense physically. The problem is that we already have one segment of the industry that relies on the customer trusting arbitary claims with no backing: LRL's. Now I'm not equating coils themselves to LRL nonesense. I'm just saying customers should stay aloof and not accept things blindly... If a pattern like that is established then we might find ourselves buying snake oil eventually.

What? I think you are saying the new coils are like chasing rainbows but I'm not sure. Have you tested the new ones?

There doesn't seem to be much discussion about all these new coil models being released right on the tails of the GPZ release - Elite, Evolution, Detech... I know a lot of people here are using GPZ's and sold their GPX's, but really no one is saying much in the US on any of the forums at all. And the Elite has been out for enough time now that some people must have quite a bit of experience with them, yet all we hear is "they are great", nothing quantitative though. So I'm just going to pose some questions here that are driving me a bit crazy: What exactly is it that makes these coils so much better? And are they really so much better? The very few testing results I've seen have been almost entirely qualitative and that doesn't say very much. I mean...the GPX still works the same and thus the coil is still just a coil. How much better can it actually get after how ever many generations of previous coils we've already seen? Why were they coincidentally released right after the GPZ? If it was just 1 company I could buy into a simple coincidence...3 companies now...Are they all using different technology to make suddenly superior coils? How is that even possible given the simple makeup of a coil? If every manufacturer out there already knew how to make much better coils then why didn't we see them before the GPZ came out? What purpose would it serve for all of them to just hold back producing these together when they are in direct competition? Conversely, if they only discovered how to make much better coils after the GPZ came out then that means it only took them a short time to figure out how to make these, so why didn't at least one of them figure it out in the years leading up to the GPZ release if it was such a quick fix? I'm not saying they aren't better and great. I'm just saying we're being sold things that are saying they are better and great with no real evidence, no real explanation about why they are even different. We know they are heavier and slightly odd sizes...what else? I mean, I don't know a lot about coils but it's not like you can just add a ton of extra windings in and expect greater results - the machine itself is tuned to use coils with specific inductive properties right? Is anyone brave enough to tear one apart and see whats inside? I'm going to be buying a NF Evolution because the only way I'll get real testing results done is to do it myself but I don't have money for the other 2. If anyone else has a Coiltek Elite and someone else gets the Detech then I'd like to meet up so we can test all 3 against a normal NF/Coiltek/Detech coil on the same machine. Then also against the GPZ just for general interest purposes. I'll be posting it to my youtube channel if I can make this happen so everyone can see if I'm able to get these rounded up into one place. I'll be in Arizona this winter, let me know if anyone is interested.

Are these to compete with the new Coiltek and NF offerings? Any idea what the "new technology" is?

Sounds dubious to me, especially the doubling of finds part. Unless I'm misunderstanding something, attaching 600 ohm headphones to a circuit designed for 4-8 ohms is going to make it quieter, might even actually need to get a booster to bring it back up to normal loudness, though maybe the SDC has robust audio control already, dunno since I don't have one. But electronics gurus please correct me if I'm wrong there... Also, the amps in detectors aren't designed with nearly the frequency response that high dollar audio amps are made with, which is what those sorts of headphones are intended for. It's like hooking a $300 pair of headphones to a Walkman from 1984...except probably worse. Or trying to listen for frequencies on a 60 year old record that just aren't there to begin with. Though I bet the sound deadening capabilities on a set of nice studio headphones are excellent, that is one positive that could make a difference. Gladly change my opinion given new evidence to the contrary though.

My 3rd Nokta works ok, it developed a problem with the VDI screen the second time out but oh well I can still see and I'm about done with doing exchanges anyways. They must not like Wyoming for some reason... The last time around I was able to have them mail me the replacement detector as soon as they saw me ship the defective unit in the tracking report so that went quicker, might ask if they'll do that for you. BTW, you might check Geotech forums. There are a couple guys that do coils here but a lot more over there. Also a decent book to read by Carl Moreland called "Inside the Metal Detector" which goes over BFO, VLF, and PI designs including coils. Might be a good read if you are planning on tearing into stuff. I've got about halfway through myself, skipped the BFO stuff.

Did you get the inductance and capacitance of that coil before taking it apart? Good numbers to have to replicate it, might not match when you get it back together if its put together any bit differently. I love the pioneering rip it apart spirit though! Just curious, how much does one of those machines cost? Did you have to buy it new or found it used somewhere? Never seen one before myself.

Lots of various interesting stuff to pull out of this data, here are some. Also probably useful to note that online/forum results (probably) differ quite a bit from the field. For instance I still see quite a few 3500's out and about despite their poor showing here, and quite a few GMT's as well, but mostly by people who don't post or go online. Also of note, I've seen some survey responses that were contradictory to other responses in other threads posted before or after the survey, nothing official anyways all in good fun but come on guys... *sorry for the small text, i had to shrink everything down so the picture wasn't gigantic on the forum.

I'll make some graphs for fun tonight, I like data visualization. If it's done next year it'll be easy to see changes visually too, or make a little animation.

I'm predicting "new in box Eureka Gold" detectors on ebay are about to double in quantity and start selling for half cost. Can I short sell a metal detector model?

A guy could sell his old used 4500 and then ebay the Eureka and get into a brand new warrantied 4800 for a couple hundred bucks.... Hmm interesting. Wish I had a mailing address to do all that ebaying/selling/shipping/receiving.

Nice stuff, I agree with Rick it'd be interesting to see every year if you were willing to do it. Would be interesting to see how much share the 4500 regains and if the very popular SDC is so popular because it fills a price niche or a utility niche. All sorts of other fun questions to think about who's answers could potentially show up in data trends over time too. Are you able to post the spreadsheet for download?