Geotech

Where would someone sell a 10-ounce gold bar? I suspect that the average local venue can't deal with it and I would not want to mail it anywhere.

Before the invasion a US nickel cost 8¢ to produce.

The issue with color screens is power consumption & sunlight readability. Though I suppose that power consumption can turn into weight if larger batteries are required. The V3 pulled ~250mA and with 8-AA batteries would run about 8 hrs. Part of that was the low f of 2.5kHz. Don't go that low, use a new more efficient display, and use Li-Ion batteries and it probably lands in the 3-lb range.

The LCD has a Boost mode icon but that feature never made it into the design. If you manage to turn on all the LCD icons it shows up but in official literature (inc the manual) it was removed to prevent threads like this. Either someone figured out how to turn on all the icons or an undoctored photo got out of FTP.

The V3 had a lot of innovation and cutting edge features. It was the first detector with color display, the second with wireless headphones, had stereo mixed-mode audio, and features like the SpectraGraph, Live Controls, and fully customizable audio tones. But where it was lacking was raw performance. Steve is right, a lot of people dove deep into the settings looking for ways to improve performance. But it wasn't all because the V3 was set to a low bar, it was because it fundamentally didn't perform as well as, say, an MXT or an Explorer. Part of the shortcoming was in the analog design and the reason for that is because the guy who knew the most about it -- Mark Rowan -- was run out of the company. In any case, there are a lot of cool features in the V3 that have yet to make it into another detector. We had a lot of other ideas that didn't make the V3 cut (the V4 was defined and started but didn't get far because all the players left White's) and I would love to design a new/better/high-performing V4 at some point. Ergo my curiosity about the acceptability of user levels. David didn't develop DST, John Gardiner did. I have no idea if 'off' really means 'off' but I'll try to find out. Sorry, I would share it if I did. Update passwords were unique to each detector. White's had a PC utility where you type in the detector's serial number and it generated the passwords. That utility was lost, along with the one that would reset your personal password if you forgot it, or if you bought a used V3 and wanted to reset the owner info. That would be a tall order, with or without me. The V3 needs extensive redesign.

That was also the case with the VX3 vs the V3i. It also argues against an upgradeable detector because then sales would likely be dominated by the base model and the company looses money in the short term.

The V3 is a counter-argument to this. It had (almost) as many controls as possible but people complained bitterly that it was too complicated to use. Even though there was a simplified interface mode (the "6-block" menu screen) for newbies and the placement of advanced features in the aptly-named Expert menus. Even adding a full interactive help system in the V3i didn't do much to curb the complaints. And many of those complaints came from dealers who were so uncomfortable with the detector they often wouldn't try to sell it*. The issue is that the user always feels he is not getting peak performance unless all controls are optimized. So they feel the need to try to adjust everything, often for the worse. With 5 controls you couldn't get in too much trouble... with 50 controls trouble comes easy. Add to this that buyers of the V3 were often newbies who felt that if they are going to buy a metal detector then they should just go ahead and buy a top-of-the-line model and skip the learning stage. The VX3 had a good solution that was never carried through. It is hardware-identical to a V3i but features were pared way back. But it actually has 3 more skill "levels" that can be activated with passwords, which incrementally add more features until it becomes a full-blown V3i. The idea was to sell these as e.g. $99 upgrades people would buy when they were ready. It was never offered. But it does beg the question: If you could buy, say, an Equinox 600 today for $700 and later upgrade it to an 800 for an add'l $300 would you find that to be a distasteful business practice? I recently read that auto manufacturers are considering this, where you pay a la carte for options that are software-disabled even when the hardware is designed into the car. Surveys indicate that this would greatly annoy new car buyers. However, oscilloscopes are being sold this way now... you can buy a basic model and then upgrade the bandwidth or enable the signal generator or logic analyzer features later. For a detector I'm thinking more like the VX3, where there are 4 levels, each of which offer a several new features that are progressively more advanced. The incremental upgrade price would depend on the price of the base model and the corresponding advanced model but, for argument, let's say $99 each and also say that a fully upgraded base model is just slightly more expensive than buying the top model from the start. And, no, this is not a hint of anything FTP is considering. In fact, I'm certain they would not. *At White's we were told, "If the dealer can't explain the feature, then we don't include it." I heard over & over "keep it dumb-dirt-simple." I still don't know how the V3 ever made it out the door.

Probably not soon.

Not really. In most modern designs the GB is applied at the demodulator (using variable timing) before the filters convert the signals to AC. But you GB the machine by listening to the ground after the filters. You could apply GB after the demods & filters, which is what the GoldBug2 does. The early VLF detectors did not have target filters so what you heard was always DC signals, but the method of GB (variable timing applied to the demod) was the same as it is now.

Technically it doesn't. Assuming you have a threshold-based detector, you set the threshold to some level. Then, as you bob the coil over ground you may hear a ground response per your first post. Ground doesn't alter the threshold, it's just a target signal when GB isn't set right and you bob the coil. You adjust the GB until bobbing the coil results in no signal; that is, just the constant threshold. The ground signal is an AC signal meaning that when you hold the coil still (don't bob it) the ground signal will quickly go away and you are left with just the threshold. Until you start moving the coil and the ground signal causes audio noise. Maybe better wording would be: "A POSITIVE ground balance means that the machines audio INCREASES in volume..." Back in the good ol' days of early VLF detectors the ground signal was DC, not AC, so it did affect the threshold. To ground balance you had to do a dance between the GB knob and the "tuning" (threshold) knob to get everything where you wanted it. That was a tough thing to explain in a manual.

Only in the CZ7/CZ70 models, the other CZs were all-analog. The most impressive all-analog design I've seen is the White's XL-Pro. While only SF, it had auto ground tracking which is an impressive feat in analog. An all-analog MF with auto-track might be possible but I wouldn't want to try it. It's funny, not only do the newest designs use micros but X-Terra/Equinox & Deus1/2 are almost all-micro. They are direct-sampling designs with almost no analog.

At White's, in exchange for getting a new engineer hire approved I agreed to make a switchable PI+VLF, other people had said it wasn't possible. The hard part is designing the TX circuit, so I did that and got it working. Then I was going to combine the SMPI and MXT circuits for the RX side, but other projects got in the way and I never got back to it. I've often thought about resurrecting it as a Geotech project because it's more of a novelty than a practical product. It's main advantage is that you can buy one detector instead of two.

Sequential has the advantage of perfect channel separation whereas simultaneous relies on imperfect channelization filtering. Sequential is also easier to alter frequency weighting. The DFX saga is complicated. Yes, White's paid Minelab to license their '360 MF patent. This was actually initiated by White's at the insistence of one of the engineers. As it turned out, DFX didn't really infringe the '360 patent so White's just wasted a bunch of money.

The old Bullseye-II was surprisingly good on tiny gold as it ran at 30-ish kHz (I don't remember exactly).

I don't know, I haven't tested much in the way of newer offerings. The F-Pulse/TekPoint have good depth but not tiny target sensitivity. I was developing a version for tiny gold in bad ground but no work on that for 2+ years, and it may never get done. Simon is seeing the Carrot with tiny target sensitivity near the TRX but I never did when I had one. I don't know that, just speculating. I had just bought a Profind 35 but it was on the moving truck that was stolen, along with my TRX and a couple of Garretts. Anyone wanting to donate a dead Profind 35 let me know.

The TRX has an IB coil which is difficult to make so I suspect minor variations in the coil may cause it. I assume the new ProFind design is IB as well (it has iron ID) and probably has a similar coil design. The 1st-gen Bullseye, 1st-gen ProFind, and all the Garretts are energy theft designs which use a simple mono coil and don't really have the sensitivity to pick up EFE. The F-Pulse has the sensitivity, but uses bipolar pulsing which naturally cancels EFE.

I can probably tell you why. The chip shortage is crazy and chip prices are doubling, tripling, and quadrupling. When you can get any chips at all. At FTP we are scrambling to sub parts just to keep things in production and the prices are eye-popping.

What you are experiencing is Earth field effect (EFE). The Earth's magnetic field affects the RX response slightly and as you rotate the coil around the effect varies and can cause falsing. It is more prevalent with pinpointers because there is a ferrite rod in the coil and the Earth field affects the reaction of the ferrite. Theoretically it can happen with any pinpointer but is more prone with high sensitivity designs. I recall when I built the first TRX prototype I used the wrong ferrite and it was incredibly sensitive to EFE, it would go crazy as I waved it around.

Simon, the issue with level 4 falsing is not unusual. Level 3 was stable on all the units, level 4 was often iffy. I always run mine on level 3 and it still (barely) detects the #9. Getting stuck after detecting a target is highly unusual, I don't recall that happening during production. I saw it in development of the F-Pulse and it was caused by the beeper/motor creating enough power supply bounce to screw up the detection signal. Are you running both speaker & motor? If so, turn one of them off, that will lighten the load. On batteries, I always recommend the 2-AA over the 9V.

There should be no diode. Some coils may have a thermistor but that's not the problem. The 4x6 is a DD coil that is completely encased in epoxy. DD coils are incredibly sensitive to coil movement (concentrics are not) and any movement of the epoxy will knock the coil out of null and cause overload. White's had fits with those coils in production, after the epoxy was poured it was baked in an oven for 2-3 days, then sat for a few weeks to fully cure. Then the final tweak null was applied and the coil was sealed. Sometimes even that wasn't enough and coils would drift months later. You have two solutions. 1) Don't run it at max sensitivity. 2) Remove the bottom plastic and re-null the coil. For #2 there is a loose winding that is held down with hot-melt. Moving that wire around will alter the null. To do it right you need an oscilloscope, but you might be able to at least make it better by using a ferrite and the detector's overload audio.

Carl from White's here...

Patents normally expire 20 years after first filing, so their '360 patent (BBS/FBS) expired over 4 yrs ago. I've seen nothing from NM or XP that looks anything like the old ML sequential multifrequency. But they do look like the Equinox's simultaneous multifrequency, which first showed up in the White's DFX. In fact, one of the MF modes on the Deus 2 has the same waveform as the DFX. That's not a surprise, it's just how you do a 5th harmonic system.

It's always a challenge to take over someone else's code. And the V3 code is probably one of the largest and most complex detector programs ever written. To make things worse, the processor is obsolete so, at a minimum, it needs to be ported to a new processor. To make things downright miserable, the V3 had some particular problems that would need fixing, some in software but also in the circuit design. The people who designed the circuitry and wrote the code know where the rocks are. Garrett will have to figure it out, could take a while. Probably faster to start with the Ace Apex.

Yeah, V3 is still one of my favorites. The SpectraGraph display has still not been equaled, or even approached. It's a shame it ended up a dead end.

He's working on a utility pipe tracer. Unfortunately the work we did at White's holds no water here. White's is viewed as a failed company with failed products.