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Just a note, but the AQ has no “holes” because of the way the two-channel sampling of signal is arranged. I would explain exactly how this is done, but....

A. I don’t understand it well enough

and

B. If I did explain it, I have some concern that some guys from Juarez would be hunting me pretty quick.

There is some loss of sensitivity when the multitone and mute modes are used and the iron ID is turned up - vs. the all metal mode. This has been described as perhaps 10%, but I believe that this has been reduced prior to final production hardware. 

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22 minutes ago, Rick Kempf said:

Just a note, but the AQ has no “holes” because of the way the two-channel sampling of signal is arranged. I would explain exactly how this is done, but....

A. I don’t understand it well enough

and

B. If I did explain it, I have some concern that some guys from Juarez would be hunting me pretty quick.

There is some loss of sensitivity when the multitone and mute modes are used and the iron ID is turned up - vs. the all metal mode. This has been described as perhaps 10%, but I believe that this has been reduced prior to final production hardware. 

I would say there are no holes perhaps in the “accepted range” when the discrimination is engaged. The disc system itself is by intention creating at least two holes, one at each end of the normal disc range. Some good targets will inevitably fall into these holes. Saying the AQ has no holes can only be true if the ground balance and disc system is turned off. A hole by definition is what happens when a good item is eliminated as an unintended result of these systems.

In other words simply saying there are no holes in the AQ system might lead people to believe no good targets will be lost when these systems are engaged, and that can’t be true. Even dual channel processing is not perfect. It greatly reduces the problem but does not eliminate the issue. I’ll write a tech explanation up when I have more time.

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9 hours ago, Steve Herschbach said:

Thanks Tony. I think in a beach setting the TDI gets the edge due to the ability to turn off the ground balance. You can minimize the GB on the ATX but not actually shut it off, so the filter is always in place. Once you engage the ground balance of the TDI the differences largely disappear. Anyway, that all jives with my experiences, so thanks for confirming. I’ve generally considered the TDI to be better for beach detecting but prefer the ATX for gold prospecting due to the dual channel processing, which helps eliminate the huge depth hole that exists on the TDI on approximately 1/4 ounce gold targets when the ground balance is engaged. You will lose over 50% of your depth or entirely lose targets that fall near or in the hole the TDI creates with ground balance engaged. This does happen on a range of gold rings for people who are using the TDI on beaches with ground balance engaged. Pick the right rings and I can create an ATX versus TDI test that would embarrass the TDI. All machines have a weak spot, and that GB hole is the TDI Achilles heel. GB off eliminates the problem. The ATX is using dual channel processing which is more akin to what Minelab uses in their gold prospecting detectors to address the issue.

Couldn’t agree more Steve with all of the above......I’ve tested some big gold and platinum rings and depending where the GB point is set, some of these rings are only picked up at 3” to 4”😳

GB Off is sensational though and that is all I run (and all I ever will) with the TDIBH on the beach. I’ve seen the results with GB engaged and it isn’t pretty. With the GB on then you will absolutely miss some gold and platinum, big and small. Personally, I just can’t accept that. Additionally, our $1 and $2 coins are high conductors and they really add up.......I detected over $1000 alone last year In just these coins that people drop everywhere on the beach and in the water. So at the end of the day, I have to dig the whole range of conductivity from low conductors to high conductors so the two tone GB on is pointless if I’m going to dig all targets......and with the dreaded “holes”.

 Tony 

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I’ve always imagined ground balance and discrimination as “necessary evils”. In other words, if I don’t have to use them, I do not. Both are electronic filters, and their use can cause lost depth and lost targets.

The TDI is the best example of ground balance off giving best performance in mild ground, but there are others, like the little known ability to shut ground balance off on the GPX 5000.

The thing is, if you use no ground balance, you will run into issues where increasing ground mineralization and especially hot rocks impede depth and create false signals to the point where you are better off engaging the ground balance to get back stable performance. I have found it is the hot rocks especially that are the issue. I can run a PI like a Surfmaster PI or TDI with ground balance off in pretty bad ground as long as the mineralization is even, spread out, homogenous. But toss some hot rocks in mild sand, and the false signals can get overwhelming.

Same with discrimination. Digging everything is the only way not to miss good targets, especially the vast numbers of good targets masked by trash. If you don’t dig that trash target off first, that masked target at 4” stays there. It’s not all about depth; there are plenty of good shallow targets in parks masked by trash. But most people hit a wall digging trash. We all usually have time constraints, and digging everything can be counterproductive when all you have is two hours. So I turn on the disc and do the best I can.

Therefore my mottos. Use a PI when you can, and a VLF when you have to. Leave ground balance off when you can, but turn it on when you have to. Leave discrimination off, but turn it on when you have to. Each of us has different thresholds for when we are forced to switch methods, and no one methodology can be said to be right or wrong as it just depends on circumstances and personal taste. The main goal is to have fun I think, and so do what it takes to make your detecting fun.

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1 hour ago, Steve Herschbach said:

I’ve always imagining ground balance and discrimination as “necessary evils”. In other words, if I don’t have to use them, I do not. Both are electronic filters, and their use can cause lost depth and lost targets.

The TDI is the best example of ground balance off giving best performance in mild ground, but there are others, like the little known ability to shut ground balance off on the GPX 5000.

The thing is, if you use no ground balance, you will run into issues where increasing ground mineralization and especially hot rocks impede depth and create false signals to the point where you are better off engaging the ground balance to get back stable performance. I have found it is the hot rocks especially that are the issue. I can run a PI like a Surfmaster PI or TDI with ground balance off in pretty bad ground as long as the mineralization is even, spread out, homogenous. But toss some hot rocks in mild sand, and the false signals can get overwhelming.

Same with discrimination. Digging everything is the only way not to miss good targets, especially the vast numbers of good targets masked by trash. If you don’t dig that trash target off first, that masked target at 4” stays there. It’s not all about depth; there are plenty of good shallow targets in parks masked by trash. But most people hit a wall digging trash. We all usually have time constraints, and digging everything can be counterproductive when all you have is two hours. So I turn on the disc and do the best I can.

Therefore my mottos. Use a PI when you can, and a VLF when you have to. Leave ground balance off when you can, but turn it on when you have to. Leave discrimination off, but turn it on when you have to. Each of us has different thresholds for when we are forced to switch methods, and no one methodology can be said to be right or wrong as it just depends on circumstances and personal taste. The main goal is to have fun I think, and so do what it takes to make your detecting fun.

LOL...Steve, you said that backwards, no offense intended. What you meant, and have said before is use a VLF where you can, and a PI where you have to.

Jim

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You are completely right Jim! At the time I said that it was from a totally different perspective. In that case I was discussing the reality of target depletion. I was ruminating on the idea of a place like Ganes Creek that was full of ferrous trash and gold nuggets. In the early days there was so much gold that you could use a VLF, skip most of the trash, and get most of the gold. As time passed, all the gold that could get picked with VLFs faded away, and I was forced to go to a PI to “light things back up”. So in that circumstance it made perfect sense to use a VLF first, then go to a PI when I was forced to.

On a beach I go the other way. I always use a PI first, and only go to a VLF if the trash levels are too high for me. Yet truthfully there is not a lot of difference between the two situations. So why the opposite thought pattern at work here?

I think it is because on a beach I find the digging to be easy and I rarely have run into so much trash that I did not want to use the PI. I also have beach detected mainly on west coast/Hawaii, where a PI has a big edge, and so again I tend to avoid a VLF.

Nugget detecting I have used many detectors, but an average machine might be the GPX 5000 with an 18” mono coil. I still love that combo. I am digging much deeper holes, and often in some pretty hard ground. So if the gold pickings are easy I would tend to grab a VLF first, especially back in the old days. The truth is in the world of nugget hunters I was probably in the minority even then. These days I am a PI/GPZ first kind of guy in most circumstances, but still more willing to use a VLF than a lot of hunters I know.

Long story short you caught me in an enlightening contradiction that I can only explain by saying from my perspective it is a beach versus nugget detecting thing. For a beach I definitely go PI first and VLF when forced to. And if I look at even my nugget detecting these days that tends to be the case. But if I was going to hit a new area in Alaska scouting tailing piles I have never seen before, I might very well go in first with a Equinox and 15” coil. I would be looking for easy pickings while avoiding the inevitable deep junk. If any area did prove to have gold, I would then bring in the big guns and hit that area hard. For most places in the Lower 48 however I am finding target depletion to be so serious that I have to not only use a PI, but the most powerful machine possible, a GPZ 7000, if I really want to stay in the game. I use a VLF when I just want to find gold, which means the plentiful tiny bits I can find anywhere there is gold. But that is more for fun than real nugget detecting, where the weight does matter.

Thanks for pointing that out.... got me to thinking! 🙂

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I can verify running with ground balance disabled on a PI gives a monster depth increase in the case of the QED.  I can get away with disabling the ground balance on my QED and it seems like the depth just doubles, especially on tiny targets.   Hot rocks are of course a problem and I've found it best to go a bit slower but the depth increase is more than worth it.  I keep wanting to try it on the beach but just haven't got around to it yet.

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Many thanks, Steve! I hadn't considered the location being detected. As usual with you, that makes perfect sense. I'm still hunting for elusive spots that haven't been previously detected, so your previous philosophy carries the same weight with me. That's probably why I so readily noticed the change...LOL. It stood out like an outhouse in the fog!

Jim

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