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About glabelle

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  1. An explanation of how VLF detectors work may be in order. When a target upsets the null between the Tx and Rx coils, there is a signal read which has a phase shift and an amplitude amount. It is the ratio between this phase shift and amplitude that is used to analyze what that target may be. A clad penny, or a silver dime, or a nickel, always has the same ratio. The ground also has a ratio - this is why you "ground balance". To ignore this particular ratio, given what environment you are in.
  2. Rich, ground balance (a setting to ignore the ground) is *always* "on" in any VLF machine. Think more of a ground balance of "0" as the same as a general ground balance set in a Tesoro machine. It is a fixed average, determined by the Minelab engineers. The way they analyze the target in software, they think they know how to separate ground noise - and well they may in many conditions. In many of their machines, Tesoro simply set a fixed "average" value (whatever that is) for mineralization. This would be akin to Minelab's "0" ground balance. Some of Tesoro's machines had an external control, many were "fixed" internally. I think it was a selling point - simplification for the user! You *can* get away without exact ground balance, but you lose that little bit of extra sensitivity. Another classic (so to speak 😉 ) case is the Classic series from Whites. There was no ground balance control (actually there was a trim pot located under the American flag sticker that you could adjust) - it was set internally (with that trimmer) to some "average" value. Mr. Bill's modification added a ground balance control knob to that unit, which improved sensitivity. Ironic, since I just completed that mod myself on a Classic III today! I'll show it to you in Nevada. I was doing some testing with my 800 today. A ground balance of "0" results is a big positive signal when the coil is lowered to my moderately mineralized test bed. If I do an auto balance, it ends up on "6". Then when in all metal/pinpoint, there is no change in tone when the coil is lowered to the ground. That, to me, is the proper way to set up a detector. I downloaded and read that CT-3030 manual. I noticed there is no mention of ground "tracking" in it. I believe their 2 settings, "Start ground balance" and "enable ground" on, refer to manually ground balancing, and when enabled, ground TRACKING. That's why it would not be recommended in lightly mineralized soils. I NEVER use tracking. Don't trust it. I sweep over a target fast+slow+ and every which way, zeroing in on it. There's too much chance of "tracking out" a weak target. The reason it is default in the gold modes, is that the ground in gold areas is usually heavily mineralized and varying, such that you have to track in order to eliminate ground noise and pick up those little "pickers". I admit, I've never done nugget hunting, but I understand the principles.
  3. I completely agree with Chase. Unless you have "0" ground condition, it cannot hurt to ground balance to obtain the maximum sensitivity to a target other than the ground. It also helps when pinpointing - especially a very weak target. When you pinpoint, you should hear no signal when the coil approaches the ground. If the GB is not correct, you could lose a weak target, either by getting a positive or a negative signal from the ground.
  4. With all due respect to GEOTECH (I've met him), he was measuring the waveform on the coil with an oscilloscope. That is a difficult way to determine how many frequencies are present. The best way to "see" multiple frequencies is with a spectrum analyzer. That is what I did. I used a pickup coil near the detector coil to receive whatever was being transmitted. When in "Multi", there are several (more than 2) frequencies being transmitted. I'm certain, the "secret sauce" is in how the receive signal is processed. You can see this in the diagrams below. The X axis is frequency (1KHz - 50KHz). Multiple frequencies are evident.
  5. This is probably pretty close. Remember, in the Equinox, all the analysis of a signal takes place in software. Naturally, this is Minelab's proprietary intellectual property, so we don't know exactly what they are doing. Being a retired SW engineer, I can venture a couple of guesses. One thing they could do is spend more time, and obtain more VID accuracy when analyzing a signal when in a slow recovery mode. If you demand increased recovery speed, they might a) Spend less time in the function that analyzes the data, or b) analyze less than all 5 frequencies, or c)?
  6. Once you pair with wireless phones, or plug in headphones, the speaker is disabled.
  7. I've seen debate about this question over and over. Thanks to Minelab's vague description of their use of Multi-IQ on both machines. I measured both the 800 and the 600 (my backup machine) and can put this to rest. They both output identical spectrums.
  8. Indeed, I was just starting to attempt to measure the output from my 800. The analyzer I was using didn't go up to 40KHz, which negated the validity of the test in the first place. The 800 was also in 15KHz mode, therefore the 1 freq. on Park 1. I thought I'd publish this as an April 1st measurement as I figured it might freak some out 😉 Anyway, I did get a reasonable test configuration setup and measured the transmit field. In Multi-IQ, it does put out multiple frequencies in ALL modes. Obviously, the magic and "weighting" takes place in the SW of the receiver. The graph included is the output for all the detecting modes.
  9. I hooked up a sensor coil to pick up the transmit frequencies from my 800. Connected to an audio spectrum analyzer I could see what was being transmitted in all the modes. Surprise, Park 1 uses only a single frequency ~ 15KHz. The amplitudes shown are relative.
  10. Steve, before you take it into the water, you may want to read this. http://md-hunter.com/minelab-equinox-battery-doesnt-work-water-in-battery-compartment/#more-13500 I would put some silicone grease in the appropriate places before submerging it. George
  11. Thanks Steve, I have a look at Fe vol. on the EQ. I knew that IB was a different way of analyzing the target - but it seems to reduce overall sensitivity/depth. Is that your experience as well?
  12. Absolutely right Steve. The worst kind of "wrap around" is when the machine detects a deep (at the limit of detection) small silver coin as iron. I experienced this with the X-terra. I've heard this occurs with other machines as well. The V3i did it. I have a new Minelab EQ600 and a Nokta Impact, but have not run depth tests as yet, since I'm going on a ghost town trip this week, and am concentrating on separating coins from iron trash. The little testing I have performed shows that the Impact with a 5" DD coil is superior, in dense iron trash, to the EQ600 - because the only coil available is the 11". I think with the 6" coil it will be fine. I really like the "Fe volume" setting on the Impact. It may turn out to be more useful than "iron bias" on the EQ600, since it appears that you lose sensitivity with increasing iron bias. George
  13. That does look good! Can you share any tips/tricks for cutting and drilling the carbon fiber?
  14. It was not a fair test. He needs to use the same sized coils on both detectors for a fair test. George
  15. Yes. The 1/8" plug is not seating well in the headphone socket. I noticed this right away with my 600 and provided phones. To have the headphone cable hanging out of the detector head is a bad swivel point in my estimation. What I did was put a 1/8" male to male cord into the detector control box, and string it along the bottom of the shaft to below the arm cup, where I tie wrapped a female to female adapter. Now the phones cord comes out of the back of the detector shaft in a much better position for swinging. It is solid enough to put a 1/8" - /14" male-male adapter for other headphones as well.
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