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ATX Ground Balance


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Doing research on my atx  I'm so glad I found this site. Atx is driving me bonkers in the salt water on the gulf coast florida    panama city beach to be exact and my trips to south beach. Problem I'm having is trying to run with factory settings with sens 13 ,   what happens is a lot of drift which is fine I can hear targets thru drift but then atx screams like it is locked on to a target  and stays that way with the yellow dots fixed on the far right screen which doesn't allow me to hit targets  even my scoop.  I then retune  and after a few swings same thing again. If I ground balance sens 13 I can run fairly smooth with some drift however only targets I'm digging are shallow.

I watched a video on ground balancing on detectors comparisons on u tube  with the infinium and atx side by side on wet sand   both were hitting targets deep  , then atx was ground balanced and lost a dime at 10 inches which it picked up easily in factory mode with sens at 13. So it looks like if ground balancing is used depth is really reduced ?  Another test they did was run sens at 10 in factory sens  and still couldn't pick up dime at 10 inches.

Not sure what I'm doing wrong really would appreciate any tips as losing faith in atx. By the way my duelfield runs smooth in the drink  , thinging its much less sensitive than the atx ?  My detector is ctx which runs smooth. I bought the atx to use in sanded in conditions  but not working for me so far.   

thanks jimmymac

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Hi Lipca    thanks for response   i can run in 13 sens if i ground balance     losing depth   wondering if there is a way to run in factory preset cant figure out why the atx wont run in prefacory mode in the water  on the sand no problem.

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Welcome to the forum!

First off, your mention of "drift" does not seem right - you may have a defective detector. Drift in my book means you tune up the detector, and if you leave it sitting on the ground and walk away, the tuning slowly changes all by itself. This is usually seen by the threshold getting slowly louder until it becomes very loud. Or, the threshold fades away until it disappears. Any modern detector operating properly should hold a steady threshold after tuning.

Now, if you are tuning up your machine in one spot, then when you move it it starts to make sounds, then the detector may simply not be tuned properly. For starters, your sensitivity level may be too high for salt water operation. Florida generally has a higher salinity level than some other places and so the salt water itself is a problem, though the ATX should still ground balance it out. If you read the link posted above however you will see it takes me a combination of lower sensitivity, increased disc, and ground balancing to tame the salt water and volcanic rocks in Hawaii. The first goal is to get stable operation.

I have a very hard time explaining to people that PI detectors in particular and ground balancing in general do not "add depth" or "go deeper".

Due to the point of diminishing returns the fact is most good high power metal detectors with an identical coil will find a metal object in an air test at roughly the same distance. This is the theoretical 100% max depth as revealed in air tests. It is the theoretical maximum distance into the ground that you might find the same item in the ground.

The problem is metal detectors also pick up both magnetic type soils and salt water. If the detector is seeing these things it blinds them to the metal object you wish to find. The classic example is car headlights in the dark. When the air is clear you can use high beams and see a great distance. However, if the air is full of heavy rain or snow, the headlights reflect off these undesired targets and blind the driver. The solution? Low beams. Less power focused more directly in front of the car removes the excess feedback from the rain/snow allowing you to see that deer standing in the road.

Ground balancing is a filter and not all that different that the way the discrimination system works. The ground signal or salt signal (or both) are identified and then tuned out. The ground effect is still there, but the detector subtracts it from the overall signal. The key word there is "subtracts". Ground balance methods work by subtracting part of the signal, and all subtractive methods create depth losses of some sort the closer any detected item gets to the "hole" created by subtracting the ground or salt signal. Signals are not perfect but spread over a small range, and so eliminating any signal usually means taking out a small range of signals.

If you have a trash target like a bottle cap and a high resolution detector that bottle cap will produce a VDI (Visual Display Indicator) number or target id number. If you try to disc just that one number, you will still usually get a broken signal, because the bottle cap actually produces a small range of numbers that dance around as you sweep the coil over it repeatedly. To reject the bottle cap completely means possibly having to eliminate a range of several VDI numbers. The catch? Any good items with similar numbers will also be rejected along with the bottle cap. Items that read just one or two VDI numbers in either direction may also see degraded results.

Ground balance works the same way. A window of response is rejected. Desired tems that fall into or near that same signal response area see reduced depths or are eliminated. Luckily most desired items do not fall into the same region as most ground signals. Eliminating slat signals has more direct impact because small gold signals and salt signals are identical.

The ground balance is a filter that is applied to the signal and depending on the efficiency of the method used, there is almost always some degradation of all target signals as compared to a metal detector running in a pure all metal mode with no ground balancing at all as measured in air tests. The White's TDI illustrates this perfectly. Turn of the ground balance and air test a nickel. No simply turn on the ground balance, and air test the same nickel. There will be an immediate loss of depth simply by engaging the ground balance filter. The amount of dpeth lost will vary depending where the ground balance control is set. The closer to the nickel reading the ground balance setting gets, the weaker the signal on the nickel itself. Normally a ground balance gets set to whatever the ground demands, but in low mineral ground there is a lot of leeway, and knowing which way to go with the ground balance control on the TDI can enhance certain signals and degrade others.

Sorry for the long winded explanation but this is hard stuff to get across in words. For the grand finale consider the White's Surf PI Dual Field and the ATX. The Surf PI does not ground balance at all. The ATX does ground balance, but immediately after a factory reset the filter is at the minimum level or as close to neutral as possible, although I do not think it can be considered to be completely off. But for the purposes of this discussion let's assume that is the case.

metal-detector-ground-balance-vs-no-gb-rejection.jpg

In the diagram above:

1. Surf PI Air and ATX Air (No GB) - here we are assuming we have found an item that the Surf PI and ATX with no ground balance applied both see at identical distance in an air test. Both units are seing 100%.

2. ATX Air (After GB) - now we ground balance the ATX and air test our item again. We note that after ground balancing the very same item cannot be detected as far in an air test as before ground balancing. This is because the filtering effect has removed some depth. In this case if detecting in pure white sand, little or no mineralization, the Surf PI will get more depth that a ground balanced ATX. In very low mineral ground, like in Florida, the ATX will perform best with no ground balancing.

Now, from a practical perspective when dealing with salt water you have a problem. The Surf PI is a pure PI detector with a pulse delay specifically chosen to ignore salt water effects. The machine is inherently insensitive to salt signals and small gold. The ATX is much hotter on small gold, and so will pick up salt water easily. This means that just to get in saltwater you have to lower the sensitivity, or increase the disc setting, or ground balance the ATX to the salt water, or some combination of the three. So while in theory the ATX is hotter on small gold than the Surf PI, just to get in saltwater you have to engage filters to bring the ATX small gold sensitivity down to Surf PI levels so as to ignore the salt signal.

3. Surf PI (Bad Ground) and ATX (Bad Ground) - Now we are on a beach that has quite a bit of darker soil content along with some magnetic soil properties. The Surf PI has no ability to ground balance or tune out this soil, and so it is getting lots of ground signals. The only way the machine can cope is lower receiver sensitivity or increased pulse delay, which lowers sensitivity a different way, plus careful coil control. Quite a bit of dpeth is lost. Note the ATX also loses depth in this scenario, but because the detector can be ground balanced, it does not lose as much depth.

Let me repeat that, it is so important. The ATX succeeds here, not by going deeper, but by losing less depth. This is a critical difference in how people think about metal detectors. people always think in terms of "getting more depth" when a more accurate way to think about it is to think in terms of "losing less depth" as compared to air test theoretical 100% maximums. It is not the detector that gets the most depth that wins, but the detector that loses the least depth. This may seem  like two ways to say the same thing but it is not. It is why I tend to have so little regard for air tests. Air tests do have value in showing what could be the max 100% depth an item can be found at in perfect conditions. However, what is far more important is how much of that depth is retained under adverse conditions, i.e. in the ground or in salt water. Anybody can make a detector that air tests great. The Surf PI is a simple easy to make in your garage circuit and it air tests fine. Yet it will not do as a gold prospecting detector since it completely lacks any ability to ground balance and so gives up nearly all ites performance in extremely mineralized ground. Which brings us to...

4. Surf PI (Severe Ground) and ATX (Severe Ground) - I am actually being too generous with the Surf PI here as in bad ground it could be running at 50% or less of its theoretical max obtainable air test on a buried item in severe ground, with the ATX getting under to double or more depth that the Surf. Yet do note that the ATX has lost depth also - it just does not lose the depth as quickly or as severely because it has the ground balance circuit working for it hard, trying to retain depth under adverse conditions. The Surf I under such conditions is at  distinct disadvantage.

So, two detectors, the Surf PI (pure PI) and ATX (Ground Balancing PI). The less mineral content in the ground, the better the Surf PI looks, and so Florida, especially the Florida Keys, is the ideal situation for the Surf PI since Florida soil runs from very low to almost zero magnetic mineral content.

The ATX looks better and better by comparison as ground mineralization increases. West coast and especially Oregon and Washington type black sand salt water beaches are the ground that suits the ATX best. Not because it gets more depth than the Surf PI, but because the ATX will lose far less depth under those conditions when properly ground balanced.

I hope this helps as it is a difficult subject to communicate.

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Thank you !   you have cleared this up for me    I have never gotten a smooth threshold on this atx   but have never run with sens lower than 13,  by drift i meant that end of swing i would get a high low noise as i returned the sweep to other side but was still hittting targets , they came loud and clear.

So if im reading your post right buying this detector for sanded in beaches of florida was not a smart move on my part. As the beaches here have low mineralization. Atx would be for bad ground?       Reason i didnt want to run with ground balance esp in the salt water is the water and gold are both low conductors.

Thanks so much for your response you made it very clear to me what im trying to get the atx to do in the salt water is not going to happen. guess will use for relic hunting and stay with ctx in the drink      thanks so much jimmymac

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The ATX will work for you just fine in Florida but I just would not expect any real depth advantage, if any, over the Surf PI. The noise at the end of swings is normal if the machine is picking up the salt - it is worse walking parallel to shore and reduced if you walk straight to the water and then straight away. So work the beach up and down instead of side to side, if you know what I mean. It is possible to not ground balance the ATX and run sensitivity high, but you have to use careful coil control to manage the undesired sounds.

One advantage with an ATX is the tones can sometimes be used to advantage, as can the iron disc for shallow ferrous items like bobby pins. The entire reason for a ground balancing PI (GBPI) however is in the advantage ground balancing offers in real bad ground. You just happen to be in one of the few locations in the world where magnetic ground mineralization is rare to nonexistent.

So yeah, I am a huge ATX fan but if I was headed to Florida tomorrow I would be packing my CTX.

garrett-atx-lake-tahoe.jpg

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  • 2 weeks later...

Hi there, 

To me it sounds as if you are running the atx on non motion mode, if so try motion mode,scan and do ground balancing you will be fine 

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  • 3 years later...

Good GB tuning and correct setting of the Disc level /These are 2 important settings/ on high mineralization .. with GARRET ATX it then allows to use a sufficiently high and stable detector setting - which is reflected in a good range ... ...

...other2 important settings... are Threshold and Volume....

...The right combination of these 4 main settings ... you optimize the range and sensitivity of the detector ... on various difficult terrain ..

 

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