jasong

It's kinda tangential to the original subject, but... Radiated EM waves decrease as 1/r, any changing magnetic field produces radiation which has both an electric and magnetic component perpindicular to each other. Static electric fields decrease as 1/r^2. Static magnetic fields decrease as 1/r^2 near the dipole/coil and then crossover to 1/r^3 in the far field which is defined relatively speaking.

The GPZ appears to have both static and dynamic components though I still don't understand exactly what it's doing enough to assume anything about how it really works.

As to the subject of field geometry, a mono coil is simply just a flat solenoid so googling solenoid field diagram will give a person a good idea of what the field under a mono coil looks like - it's not a cone. On my old computer I have models I created in an FEA program when I got curious myself. 

I couldn't model DD's in that program since they aren't radially symmetric. But I can guarantee they aren't blades since there is no coil geometry that creates a blade or wedge shape. In fact I believe it's a physical impossibility, if one knows vector calculus they could probably prove this since it would imply the curl of the magnetic field is zero if I'm remembering my electrodynamics courses correctly, only possible when i or B = 0, magnetic monopoles, etc in other words cases that aren't metal detectors.

The DOD coil has a weird semi circular or rectangular TX coil so it isn't going to look like a DD or mono, but probably closer to a mono.

Once upon a time I got a degree in physics and did research in pulsed EM. Those days and memory have faded though.

As to the subject of the original post, I had that happen to me today too coincidentally, screaming target about 6 inches deep, dig more, go to pinpoint still screaming and then bam, gone. I think it was just a really nasty hotrock but I'm going to hike back again with my 4500 to double check sometime.

I was wondering about that too, in places like Chemehuevis littered with all these impossibly tiny pieces of wire mesh you could just kick the 4500 into Enhance or even Salt Coarse and completely pass over all the tiny annoying trash bits but still hit on the 1/2+ grammers deep enough.

Wondering how much the Very Deep mode loses on those bits of gold compared to high yield or general? 1/2 to like 3 grams, pretty common finds.

Barry, that's why I said "or even just allow basic geometries through KML". It's easy to draw out features using the basic geometry tools in GE, lines, rectangles, etc. In fact I still do this on my phone despite having more capable features when prospecting because it's quick and easy and does the job. One can just import their "map" as a "track" and it need not be high resolution to be useful.

It's not a lot but it's better than nothing.

Also to consider is that the 7000 screen resolution itself is probably not too great in the first place, and also they appear to be internally restricting the memory at least when it comes to tracks because you are limited to only a small handful of saved tracks. So some of this conversation might be moot without Minelab opening things up a bit.

But once I get settled down I'll have some time to dig around and see what I can find, my machine is packed up right now.

Norvic, thanks I can't wait to get out swinging, I've been walking around the frozen, windy, gold-barren wastelands of the north familiarizing myself with the machine and I'm ready to start digging something real!

Ok no problem then I can write one up. It'll be about 10 days though because tomorrow I'm hitching my trailer up and hitting the road cross country and will be swinging the Z in the goldfields for the first time since I've received it. I'll have more free time once I move into town into an RV park.

I like programming, if people have any other ideas down the road too I'd be open to trying to implement them. I'm mostly limited to scripting type stuff though, Python, Java. I can do a bit of C if compiled solutions are needed. I'm all about maps too, if I can figure out a way to display raster images or even just allow basic geometries through KML conversion I'm going to try to do that, but chances are slim. I really think eventually Minelab will see the benefit of that and implement it themselves though in a software update.

I'm pretty sure no one has to worry about showing up to their secret patch only to find the Google Maps camera car taking photos for their next Streetview update.

I was going to write a Python script to automate conversions, but if people don't trust Minelab or Google to not thieve their lucky charms then I don't see how anyone will trust software written by other prospectors, even if it's uncompiled and transparent...?

I posted this in another thread, but if Minelab updated the software to allow KML/KMZ (its just plain text, a widely established format, and really has nothing to do with Google anymore), then we could at least transfer rudimentary maps to the GPZ. I commonly draw out aerial reconnaissance like faint 2-tracks, quartz reefs or blowouts, rapid soil changes (faulting, gravel age delimination, etc), old prospects etc in Google Earth then swap them to my phone. Plus with the option to save tracks as KML there is not a file compatibility problem for transferring anymore, basically every mapping program on the planet accepts KML these days.

Nice gold. Sooo...what were the tips? 

I'll probably just try to make one based on those pictures. I have no mailing address anymore (back to full time prospecting), that's why I was hoping to find a dealer I could just visit in person.

Hopefully someone in the US decides to make a full cover, that looks a lot more complex, well at least for this guy who's sewing experience is limited to repairing my pants and boots with dental floss. 

Business opportunity for some enterprising individual. Something in a light earthy color would be great so it doesn't roast in the sun or stand out like a construction cone. Desert tan, sage green, etc.

What I'm looking for is a shade, like come with mini LCD monitors such as this: http://www.ebay.com/itm/like/311285715900?lpid=82&chn=ps

Even with the backlight it's hard for me to see the screen easily. Something like this would work well.

I see some being made in AUS but is anyone making or selling them here?  Minelab - these should be standard OEM issue with the 7000. Especially considering the plastic body scratches easy and the screen is now the main control unit and its very difficult to read in the sun.

Those Converse Rapid Response are the best boots I've run across as far as comfort and durability goes and the composite toe is awesome. Never gave me trouble on my 4500, and they have less metal than my 5-11's now which themselves don't give me trouble on the 7000. Bates are junk and don't stand up to every day abuse. had 2 pair go bad fairly quickly. I tried some 5-11's after reading Reebok was using cheaper materials when they bought that Converse Rapid Response model, but these 5-11's are definitely flimsier than the Converse and I'm going to give Reebok a chance now.

For what its worth I just did a ton of air tests on my new Z yesterday with a bunch of different settings and compared it to my 4500 since I can't get out and hunt gold right now. It wasn't able to hit a 0.45 grainer no matter how I tweaked it (neither did the 4500). It did hit on a 1/4 grammer that was half quartz (so like less than 1/8th gram gold) about twice as deep as the 4500 though. But, from my rough and inexperienced tests I don't think the Z is going to be dislodging VLF's from my arsenal.

Also for what it's worth, what I saw was running without audio smoothing makes a big difference on hearing both smaller stuff and stuff at depth, which is something JP was saying.

I made a chart but seeing the reaction to the last chart that floated around I decided against posting it. 

Oh yeah, also gave it a go on some Gold Basin meteorites and surprsingly, the 4500 was equal or outperformed the Z in all settings I tried, which wasn't the case with gold, kinda surprised me.

 

Some may say there is not much of this type of gold out there. I would say in response, if most of us are using detectors that perform poorly on that type of gold, how does the fact that we don't find much prove that it doesn't exist? Truth is that there is loads of specimen gold out there and I think the GPZ will be finding a lot of it in the coming weeks and months.

 

Been thinking the same thing and unable to phrase it succinctly like you did. I'm kind of surprised so much attention in the detecting world has been specifically on just old patches and not taking the Z to places with potential for entirely new discoveries where the GPX was severely handicapped. There are a lot of places in the US where it could really shine. One problem is that some of them produce extremely recognizable gold for others who do the research so posting results could be uh...problematic and we may not be seeing a lot of results online by the serious prospectors. 

I'm still waiting for mine to be delivered, but one thing I'd like to see software wise that doesn't appear possible from reading the manual is the ability to import rasterized map layers or KML/KMZ. Basically functionality to match any smartphone these days - the ability to realtime navigate over topos, geologic maps, your own maps you create in GIS, maps of placer prospects and mines, etc etc. There are tons of good sources out there nowadays, all free. If I still have to pull my phone out to see them then I might as well still use the GPS on my phone which makes the detector GPS useless to me especially considering the screen resolution is fairly low and my phone can show gridding much much more accurately than the GPZ, which would have been the only other use I can see for the onboard detector GPS.

Also, the memory is woefully inadequete, not sure what they are using for the brains inside but nowadays having a few GB onboard is normal without having to add any external SD card on. I can only assume they are intentionally crippling or restricting the tracks storage space in the software so I'd like to see them bump that storage up - tracks only take a few KB.

I agree, I think we'll see software updates at some point too, the detector appears to me designed for that purpose. Worth throwing out thoughts into a thread at least since they are reading this forum.

Reading these I'm actually kinda surprised people don't drink more. 1.5 gallons a day while prospecting is pretty normal for me too and I'm not even a profuse sweater. During the summer it's more than that. I'll drink 16 ounces on just the hike in, not sure how someone could survive off just that all day...ya'll a bunch of desert tortoises or camels out there. Energy bar and a banana to snack on, get my electrolytes from those.

200,000 years of human history can't be wrong. Water: The Thirst Mutilator!   Definitely down with the lemon squeeze though.

9x12 for a smaller coil and 18x14 for a bigger one. The big is the one I really want but I suspect it'll be an arm killer. So I guess what I'd really want in the coil department is for Minelab to figure out a way to make them all lighter in general, if that is possible in any way.

I think the 80% operator 20% machine is pretty accurate. Patience, perseverance, ambition, knowledge, and field experience account for more than any 1 machine in my book. The maps/phones/etc are a good point too though. Google Earth Aerials, the first Droid phone release, and various historic and geologic map overlays accounted for more finds and discoveries than any 1 detector ever has for me.

On the subject of other coils, I just talked to Nuggetfinder and they said they will not be making coils for the 7000 due to the security chip and patent. So, depending where a person stands that may be a potential negative, I'm assuming no 3rd party coils unless a company makes a deal with Minelab for encryption keys and whatnot.

Nice, wish I had cable to see it!

Well, that's honestly pretty impressive... To snag a one where you did as quick as you did with just the default settings on the Zed tells me a lot. That's one of the most flogged gold fields in the State, probably one of the most flogged in the country at this point now and a lot of those guys camped out there go weeks without a nugget.

Did anyone give the 7000 a try on a meteorite out of curiosity up there? I've been wondering how they sound of on them.

By wide open I mean running it at a point where I feel I have reached close to max sensitivity while still remaining fairly stable and quiet: Stabilizer 5-8 clicks higher than normal (less stabilization), RX sensitivty 12-14 (out of 15 on the 4500), ability to use any timing you want (mostly Sharp and Sens Extra for me), big mono coils without a lot of EMI, small monos without a lot of ground noise.

Steve, do you mind sharing how you did at gold basin? Its ground i'm really familiar with and I'm curious if the 7000 pulled up any nuggets for you. Looks like Docs vid is there too and he got a couple dinks out of an old patch.

Did it seem necessary to run in difficult? My experience had been running the 4500 wide open with no probs everywhere except a few small tougher hot patches so was surprised to see the zed in difficult. GB to me is some of the mildest quiet ground ive detected.

For me a hydration pack is essential, even during the winter months when it is cooler out, plus I like having a bit of extra storage for lunch, phone, radios, etc since the truck is usually too far to hike back to for water and food. They also stay on me better than that Minelab harness. For the past few years I've used a Camelback MULE and a bungee for the GPX and liked it but I always wished it had front pockets on the arm straps so I could access things without removing the pack. I just got an Ultimate Direction Wasp to try out this year but now that I've received it, it seems a bit smaller than the Camelback and potentially a bit more flimsy. I detect 5+ days a week so I'm hoping it stands up to abuse, especially since the GPZ is even heavier now.

Just curious what other people use? Anyone have a good hydration pack that is strong enough to support a GPX/GPZ and has easy access storage pockets on the front straps? Is there a better solution out there?

Good points, lode is so often overlooked, gotta think the 7k might have a chance at pulling a few new reefs up from the results we've seen so far. I'm kinda looking forward to using it on ore piles too, I've gotten lazy and if I don't hit anything with the GB2 on the outer layer I move on to the next one, I know others do the same since very rarely are they raked down. 7000 might punch a bit deeper on the species and bring new ore piles to life too - some of my best gold finds have just been a big pile of quartz that some other kind gentleman already dug out for me.   Built a 4" impact mill for those special piles.

I'm trying to wrap my head around the difference between the Audio Smoothing function on a GPZ and the Stabilizer on a GPX. I just watched your new 4gm video and the 7000 seems to be running really smooth with no Audio Smoothing. I know if I tried running my 4500 with no Stabilization it would be painful.

Is this because the 7000 has better ground balancing and noise cancellation, or because Audio Smoothing and Stabilizer are actually different in some way? Or can we think of them as similar or the same?

Also, somewhat related I notice in your videos and lot of other Aussie videos which I am watching for the first time that you guys keep your thresholds pretty audible. I've always run mine so there is only a very slight almost inaudible background hum. What I'm wondering is on your 4 gram video Minelab just posted, do you think you would have missed that really faint signal if the threshold was set lower? Thanks.

I hear ya, last year I wrapped up my first NOI level operation with a small washplant and a backhoe and got a nice education in mining regulation which did take months. The BLM took like 3 weeks jut to process my bond, not sure how hard that could be. If I had gone to a full POO (suitably named!) level I'd still be waiting for permits today probably, if not for another 5 years.

But...I've never had so much fun in my entire life as going in and tearing up an old patch with real machinery and metal detecting it though. Can't wait to do it again in fact next time I'm just skipping the washplant and just dozing/detecting which hopefully streamlines the NOI too.

I'm printing your posts out, JP, to keep with my user manual for reference in the field as I learn the 7k. Good stuff.