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Geotech

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Everything posted by Geotech

  1. The waveforms look the same but there is quite a bit of difference between them. The Deus2 actually looks a lot more like the DFX than the Equinox. It's always better to look at the coil current when figuring out MF waveforms. That can be done with a pick-up coil if you know how to do it.
  2. If you've ever had your luggage "swabbed" in airport security they are doing the same thing. It would be amusing if TSA used rats instead.
  3. As far as I know, the 5 changes have been done. I haven't seen any of it except for the 8" coil. The batteries are supposed to drop into the arm rest tube a la Tarsacci. This eliminates the battery pack & cable which is good. But IMO the pod also needs an overhaul and my recommendation is we don't continue without that. I read the Kellyco page, OMG that's awful. I'll see if I can get it removed.
  4. That's exactly how I measure the responses of various coils. I take the demod outputs straight to an oscope and measure real signal strength. That would not work for measuring the overall response of a real detector because it bypasses all the filtering & DSP, but you could take the signal off the headphone jack and put it on some kind of meter.
  5. R9 is one of the limitations to earlier sampling. If you want to kill 2 cats with 1 stone then raise the value of R9 to, say, 2.2k or maybe 3.3k. This will lower the power dissipation and speed up the diode clamp recovery. The trade-off is it also raises the thermal noise but the SL already runs pretty quiet so it may be acceptable. Unfortunately the SL sample delay is set by firmware so you would also need a solution for that.
  6. Dimed, I use a metronome app on my phone sand and just listen to the ticks, it's pretty easy to synchronize the sweep reversals on the ticks and still listen to the target responses. Steve, you are right that a mechanical sweeper would be best but that's quite a project. I use a much simpler jig made of 2x4's: I make it ~6 feet long and glide the coil right on the top board to the beat of the metronome. Targets are placed on the 3" tier* (nail-quarter-nail) which is marked in 1/2" spacings** so now I have precisely repeatable depth, target spacing, and sweep speed. There is also a 6" tier so I can do a deeper test or a staggered-depth test. I can also place Monte's nail board on a tier and test that. I don't think it's necessary to take the audio out of the equation and, in fact, it could be really tricky to do that. I'm listening for 3 distinct audio responses and as the targets get really close together this becomes a very rapid-fire sound that might be tough to "meter." With everything else tightly controlled, it's not too hard to hear when those responses start to blend. I came up with this back at White's and did a bunch of testing on all sorts of detectors, new & old. At that time the Garrett AT-Gold was the best at about 1-1/2" minimum spacing and the Tejon was second at 2". Most all other detectors were around 4" including the Deus which had 1st-gen firmware before they got serious with recovery speed. The old analog XL-Pro was around 8". * not 3-1/2" as I said in the prior post ** I cut shallow v-notches for the nails so they don't roll around
  7. While the components can handle the higher voltage, Tony makes a good point in the other thread: be mindful of the extra heat generated. A lot of people have successfully run the SL at 14.4V but any higher than that requires some careful diagnostics before you call it done. Otherwise you could end up cooking the circuit.
  8. Jeff, you have exactly nailed my biggest 'peeve' concerning all these separation tests: they simply don't reflect a realistic hunting style. I mentioned this in a video Calabash did showing coin/bottle cap separation. Using super-fast super-short sweeps he showed that the Deus II would ignore the BC and detect the coin. But right at the end of the video he inadvertently did a couple of normal sweeps over the combination and the Deus barely made a chirp. If, using normal hunt sweep, you don't get a good enough response to say, "Hey, what was that?" then it's a fail. I'm not picking on Calabash, it seems that everyone is doing these tests like this. But nobody does normal hunting with a 3" sweep at a blistering speed. Yes, it might be used for zeroing in on a suspected target, and for that these test results are useful, but you need the normal hunt results first. When I test separation I use a 1 meter sweep at 1m/s set by a metronome. My preferred target arrangement is a silver quarter placed between 2 transverse-oriented 16p nails, all at a 3-1/2" depth. I reduce spacing until the detector can no longer issue 3 distinct target responses. A lot of people test by placing the nails longitudenally but this becomes a test for a co-located composite response instead of a separation response. If you understand why nails give a double-beep when swept longitudenally then you will understand the mechanics of this test.
  9. A major difference between a resonated (cap) sinusoid and non-resonated square wave is that the square wave approach is wide band even for SF modes. This means a higher chance of EMI. In a demod-based design there is opportunity to filter but it will always be after the preamp so you run the risk of experiencing Dankowski's silent EMI problem. In direct-sampling systems (as are the Equinox and Deus II) there's little opportunity to filter until you hit firmware and that could be even worse. However, I haven't heard too many complaints about the Equinox which I assume was the first square-wave driven wide band direct sampling SF detector on the market.
  10. Probably not. Once you design the TX circuit for multi-rectangular drive then you just use a square wave to drive single frequency. That's how the V3 and Equinox do it and it works very well.
  11. The Deus is likely switching in different resonant capacitors depending on frequency. In MF you don't use resonant caps.
  12. They probably have a better PI design in the ATX, but it's overweight and desperately needs a new body. The V3 was a marvel of software development but the hardware was sub-par. I doubt anyone will be able to take the existing design and do much with it.
  13. The only detectors that White's made that are worth continuing are the MXT-based designs (GM-24k, MX-Sport, MX5, etc), the TRX pinpointer, and the TM808. Garrett is making the GM-24k and I expect they will not make any other MX models. I think they will never make the TRX because it adds nothing to their already-dominant position. The TM808 would be a good addition, maybe they'll eventually add that one. Otherwise, I'm at a loss as to why Garrett bought them in the first place.
  14. The TDI-Pro-Oz is identical to the TDI-Pro except it has a normal mono coil instead of a dual field coil. The DF coil has some lift-off issues on severe ground.
  15. I designed the TDI-SL and deliberately made the PCB to fit either the metal case or the Beachhunter case. I had the factory build 3 prototypes, they tested fine but mgmt wasn't interested. A few years after I left they finally released it. There are some mods that people have done to the SL which slightly improve it for nugget hunting. I doubt the BH would benefit as much. The bigger battery is probably the best upgrade.
  16. The TDI Beachhunter uses the TDI SL board which I designed to take 20V, even more if you swap out a few caps. My prototype has fewer controls, I don't remember exactly and I'll need to dig it out to see.
  17. I have an original prototype I built at Whites, it's a little different than what finally got released years later. I haven't thought about selling it but might consider it.
  18. I know this is an old thread but I would not recommend using the TDI Beachhunter underwater. Both the coil and the case are notorious for developing stress cracks and leaking. I would consider it splash proof at best.
  19. On Sundays the place is usually deserted. When I used to visit I was often the only one there on weekends. When the factory is running on Saturdays they all park off the left side of the photo. My office is the first window to the right of the main entrance. Haven't seen it in 2 years.
  20. Ha! No, I just moved to Republic, WA which is a tiny little gold mining town. Spokane is 2+ hours away and now the snow is coming down.
  21. I found one RNB 6200, it's on the way. Todd at CentervilleNW says he plans to have new battery packs made in the near future. It's pretty easy to find Li-Ion 4s2p battery packs but all that I see have the cells in a "square" configuration whereas the TDI requires staggered cells in order to fit. I could build my own packs but I'd rather pay a little more and not do the work.
  22. Looking to buy a couple of TDI Li-Ion battery packs. All mine were stolen, fortunately the detector was not. Need to be in good usable condition.
  23. I've moved from Oregon to Republic, WA and am looking for anyone familiar with prospecting in this area. Ferry County has produced somewhere around 4 million ounces of gold and still has active gold mining going on. In particular, I'm looking for places that would be good test grounds for metal detectors. Feel free to respond on the forum, or via PM if you prefer. Thanks, Carl
  24. You are correct, Minelab deserves credit for actually getting things done. And they've done a lot of innovating, most of which has never been adopted by other companies. Like BBS/FBS, 2D target analysis, flutey tones, and everything they've done in PI. And, yes, the Legend has a lot of the same looks & features of the Equinox. I just don't see it as being a Big Deal. No bigger than when everyone added tone ID after Teknetics the Old came up with the idea. It's not a requirement that a new detector be original or innovative; most are not. And sometimes a detector that has a lot of innovation fails in other other key aspects, as did the White's V3. I just don't understand why NM is getting so much grief over this. Did Garrett get this much criticism over their Apex (which, functionally, also seems to closely mimic the Equinox)? I only remember they got criticized for lack of waterproofing. I'm not defending NM because FTP might also do something similar. From what little I've heard, I'm pretty sure we won't, and no time soon, either. I have ideas that I strongly believe would take us past MIQ but no one is interested, and like the stuff we were working on at White's I suspect it will never see the light of day.
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