Jim in Idaho

I think Reg has come around on this, now, John. but he doesn't know, from what he's told me, exactly whats going on either. This whole thing may be just an "unintended consequence" of something Whites changed when shifting to the SL version. Jim

Man, that's great! I never find that gold like that! Jim

It surprised me, too. When I first started testing my coils, before the battery tests, I just wanted to know what to expect from my detector. I was disappointed when I tried cutting nickels into small pieces, and the detector couldn't see them very well. Then I tried lead shot, sometimes flattening it. That also wasn't very promising. I usually couldn't see anything smaller than 3 or 4 grains. Then Reg Sniff told me the pulse width used by Whites was optimized to get a reaction on gold. So, I bought that little 1 grain gold bullion bar. I was really shocked that the TDI SL had no problem seeing that....even with the 12" DF coil. I guess, from an engineering standpoint, it's possible to optimize the pulse width for whatever metal you wanted to find. Nickels electrical reaction is similar to gold, but nickel is much lighter (lower SG), so a 1 grain piece of nickel would be 2X or 3X the size of the same weight in gold.So when you're testing, there's no substitute for gold when testing a PI. in my experience, the VLF's are less critical about the metal used...but that's just my opinion. Jim.

Steve, I can't explain it either. When John first mentioned that to me, maybe a year ago, I thought he'd been smoking old kangaroo hides. Everything I'd read had said that GB off gives the best depth. I needed mine on for the places I detected, so never thought about it much. I hadn't communicated with John for several months prior to the tests, and he had no idea I was doing them. I was as surprised as anybody with the results.....kept redoing them thinking I'd made a mistake. But Reg told me, after I gave him the results, that he thought Whites had changed something in the GB circuit on the SL. I've never heard from Whites on the subject, though I've heard from them on the voltage comparisons. Maybe they've figured something out on GB? Who knows? All I can do is post my results. I'm not trying to convince anybody of anything. Jim

The GB works fine. I've never had a problem getting it to balance anywhere I've used it. Jim

Not 1 gram...1 grain. I can send you a pic if you need one..LOL The bar is about 3/16" long x 3/32" wide. It's in a plastic card, so I can't measure the thickness. jim

No Steve, no mods. All the tests show is that having the GB on increases depth. There's a slight increase by turning it to max, but even at the lowest setting simply turning it on makes a significant depth difference. I just finished the new tests on the 7.5DF. Not much difference due to battery voltage, and turing the Gb on made little difference on the 1 grain gold bar. But it made a +15% difference on the nickel. Battery Voltage tests Whites TDI SL 7.5"DF coil Freq: centered: Pulse Delay: 10: Gain: Max !6.2V Nickel 1 grain Gold Bar GB OFF: 10.75" 2.75" GB ON Switch in "all" Min. 12.75" 2.75" Max. 13.25" 3.00" GB On Switch set in "low" N/C N/C 12.3v Nickel 1 grain Gold Bar GB OFF 11.0" 2.75" GB ON Min. 12.75" 2.75" Max. 13.0" 2.75"

My tests showed the improvement on both a nickel, and a 1 grain gold bar. The improvement was much less with the Miner John 5 x 9 folded mono. The way I conducted the tests was specified by Reg Sniff, and I conducted them at his request. The tests were posted on Whites forum, and Findmall, if anybody is interested. The following tests on the 7.5DF I made a mistake, so should be ignored. I haven't had time to do them over. Jim

Steve, if Johns unit is defective, than so is mine. My testing results, during my battery voltage tests, exactly mimic John's machine. There's a definite improvement in depth with the GB on, even if it's set at it's lowest level. And, with the 16.8 v battery pack, my SL can clearly see a 1 grain nugget at 3" with the 12" DF coil. Jim

Lithium-ion packs for all my Whites detectors. Easily removed for charging. Bumping the TDI SL pack to a 4-cell really wakes up that machine. 16.8v instead of 12v. Doing that with my other Whites units would damage them, however, so run a 3-cell Li-ion in the GMT and DFX. Found a charger that lets me set the output voltage and current, so I can use the same charger with both packs. But, I need an extra pack for the SL....it only gets about 5 hours on a single charge. I plan on building another this winter. Jim

I'll tell you, Mitch, that's a good policy anywhere in the outdoors anymore. I never approach strangers when I'm out alone....nothing good can come of it. too many pot-growers, drug-runners, etc. I make very effort not to be seen, too. jim

Well, I figure people aren't out to steal my truck, so I put the keys in the bumper of the flatbed. If they really want to get in and steal my gear, I'd rather they just used the key anyway. My big concern is simply being stranded. Thus the keys stay at the rig. I don't even have electronic keys on the old Dodge. Jim

LOL...I don't blame you. Especially in places that get a lot of human activity. My biggest fear, though, is wearing a hole in my pocket, or something, and losing my keys. I'm usually WAY out in the sticks, and alone....real cause for concern. I'm now WAY too old to walk 30 miles to civilization....Ha! jim

The Otter Box is fine, but what do you do if it ends up floating down the river? The idea of hiding the keys at the vehicle is that is where they're needed. Having them in the Otter Box while floating the river is no different than having them in your pocket while hiking around....if they end up lost, your vehicle is worthless for getting you home. Just sayin'. Jim

I'm with Strick. No experienced outdoorsman ever carries his vehicle keys while hiking around. I have carried my wallet, at times, but my wallet won't get me home...LOL. Best to leave both at the rig, or hidden nearby. Jim

Nice writeup and pics, Tom. I enjoyed that. jim

I've got one of the old Master Hunters. It was the first detector I ever owned. It came with two sets of dual coils. You can select which coil you use by flipping a switch. Mine still works, though i rarely use it. A few years ago, when it was the only MD I owned, I used to locate my property boundary stakes. Jim

LOL...nope, I was thinking of Steve Howard, Steve. My bad.

Yeah, it might be a bit much. I'd like to find a charger with an adjustable final voltage. Then I could limit it to 16.0 volts. That would also make the battery pack last longer. I think Steve H said the SL could handle voltage up to 18.0, but I'm not sure of that. Best bet is to stay at, or below 16.0. One of these days, I'll get around to doing a test to determine how much extra depth, and/or sensitivity you get from the increased voltage. I do know my SL will detect a 1 grain gold bar at 1 1/2" in an air test, which isn't bad. Jim

I've been running a 'reidman" 16.8 volt pack in my SL for about a year. No problems so far. Haven't done any tests to see if the extra voltage helps. Jim

Many thanks, Steve....looking forward to reading that tonight! jim

All the best on your surgery.....I'll add a couple of prayers tonight. I hope Hard is right on Whites improving the SL. Jim

I'm already using a 4 cell L-ion pack. 16.8 volts with a fresh charge. Steve Howard said that was about all the voltage the SL could handle. Reg had a couple of mods that allowed a faster sweep speed without losing sensitivity on small gold. I've got the writeup on those, just need the right technician to get it done. I was a radar tech in the Air Force, but Reg said it required somebody with experience in current devices. Jim

If you find somebody doing the mods, please post it. I'd like to have Reg's mods for the SL done to mine. Need somebody with micro soldering skills from what Reg told me. Jim

Last I knew, Reg had quit working on mods. Said he had a friend thinking about doing it, but no decision so far. Jim