Understanding Depth Indication on Garrett AT Pro

You don't read depth. It's very seldom accurate. If you are in good clean dirt it will be close with a quarter, but a can at 8 inch will read the same as a quarter at 3 inches. I guess depth more by raising the coil and using the TRX than the depth gauge. Your coil is an inch or 2 or 3 above the surface so a target showing 6 just below the surface ain't that far off. It's just the machines best guess base on a coin sized object.

Are you hunting pro mode? Depth is more by sound than the gauge. I don't even look at mine.

When using my Fisher 1266, depth is better indicated by tone than anything else. That may also be true of your ATP. Also, I use my hand held pin pointer a lot to determine general depth. My Garrett Pro-pointer II will not even ring if the target is deeper than about 4" . If I get solid or nearly solid tones on it, I don't even unsheath my Lesche and instead use a coin probe to recover.
I just got an Equinox 800, which is my first detector that has target ID #s and a depth indicator. I only have a couple of field hours on it but so far, I would say the depth indicator is only " roughly right" and this machine is supposed to represent the latest technology.
IMO, there are only two depths to concern yourself with : Deep ( anything over about 6 inches) and Shallow ( anything from surface to 6 "). Learn to tell the difference between those and you will be just fine.

I agree with the rest, once you get some time behind the coil, you will start "hearing' the depth based upon the proportional audio..As well as raising the coil off the deck to sort of see what you are dealing with target depth wise...

Although, the AtPro hits things so hard, it is my most difficult rig to distinguish target depth audibly...I'm running it 3 clicks down from full sens even, which is helpful in this regard...still hammers deep...

I'm sure the Members who use the AtPro for years will chime on in with some tricks and advice, but really, its a matter of concentrating and practice and thousands of targets dug and considered and remembered in order to train your ears....

All of a sudden, you will get it, and without even thinking, your mind will process the audio signals from the very first ping...."Thats a Q at 3 inches"..."Heres a dime in the grass" etc...You wont ever look at the depth gage again.

Pinpointing is more accurate on coins laying flat than if they are at an angle. I use the pinpoint button but I also wiggle back from from a couple different angles. I have no idea why but it seems when I'm off it's always about 3 inches closer to me than I thought.

If you don't have one you should consider a handheld pinpointer. They make detecting a lot easier.

Agreed with the others. It will take time behind the coil to get a true feel for it. I use the pinpoint on my ATP to get a general idea where the target is. Also, it will give a somewhat accurate reading on the depth, but it's not always precise. If it's a solid, loud tone reading 4 or so inches I will use my pro pointer AT to verify. It will pick it up within 3 or so inches.

Remember, it is designed based on a coin sized target at certain depths. Not all targets are going to be coins or even coin sized. I've found I can determine a pop/ beer can from a coin with little difficulty. A large target 6-7 inches deep is going to give a nice solid tone the same as a silver dime an inch or two down. If you pinpoint or follow the tone with your coil and it's solid for several inches in one direction or the other, it's most likely a can or bigger than coin sized target.

I would recommend using headphones if you are not already. This will allow you separate "good" and "bad" tones. It will give you a clearer picture of what you're hearing and you will be able to get a better indication of the depth as well....if that makes sense. Also, run in pro zero mode...Makes a big difference...

Hello V! Good advice given above. I use the AT Pro and don't even look at the depth gauge. On many detectors they are not that accurate anyway. I rarely even look at the VDI (target numeric number readout) except to confirm a surface zinc penny (75 - which I don't dig) and a nickel (50-53) vs pulltab signal. And FYI I have my detector set to Pro Zero, nothing discriminated or notched out, no iron audio. I hear everything and let the variations in tone pitch and hardness tell me all I need to know about the target.

On the Pro, a surface / shallow coin or similar target (button, token, ring) gives a very crisp sharp hard signal. Kind of a "blip blip" as you swing back and forth over the target. If I hear that "blip blip" I pull out my Garrett Pinpointer to accurately find the surface or near surface target with that, and with minimal probing or shallow digging to recover the target.

As the target gets deeper, the sharpness of the tone begins to soften, though the pitch remains the same (low tone for iron, mid tone for nickel foil pulltab and gold, and high tone copper or silver).

Today I dug a few silver mercury dimes and plenty of wheat pennies. They were fairly deep, say 4-7" or so. They all gave the same high "tone" as a surface penny or dime, but the signal was quieter and softer. This told my ears (and single brain cell) that they were good deep targets. No need to look at the VDI or depth indicator.

Hope this is of help and good luck in your detecting!

My AT Pro would typically max the depth indicator on finds very close to the surface.

Thank you all for your input and advice. It makes a lot more sense now. I've been learning to listen to signals, but I'm still unsure of what I hear, so I tend to look at all the info on the screen to help me determine what and how to dig.

Call Me V said:

Thank you all for your input and advice. It makes a lot more sense now. I've been learning to listen to signals, but I'm still unsure of what I hear, so I tend to look at all the info on the screen to help me determine what and how to dig.

Click to expand...

I'm sure you've seen folks say, "dig everything". I did this for the first couple of months with my AT Pro in an extremely trashy park. It taught me tons about tones. I had hundreds of pull tabs, can slaw, bottle caps, etc...but I also found a lot of clad and other things.

From time to time, when time permits, I will still dig just about every tone. If you do this, you will become very proficient very fast...HH

Call Me V said:

....How do you read depth?

Click to expand...

First off, congrats on the switch to an AT Pro - wow, that was quick!! Careful...you're starting to show all the signs of full-fledged MD addiction You'll know you've really got it bad when you start showing up to hunt with the ATP in one hand, the Ace in the other, and swingin' 'em simultaneously

Anyway, sorry I'm late to the party - I just saw this thread today. You've gotten some pretty good info already, but I thought I would add my 2 cents - the more opinions the better, and somewhere amidst it all you'll find what works for you.

I started with an Ace 400 and moved to an AT Max earlier this year. The ATM is much more similar than it is different when compared to an ATP. Both have proportional audio (assuming you're running in Pro mode) and depth depiction/pinpointing behave the same way for sure.

Unlike what some others have implied, I actually consider the depth indications on the Garrett machines to be quite accurate, as long as you keep in mind the important caveats. First, like others have mentioned, the pinpoint feature is calibrated based on a coin-sized object - larger objects will register shallower than actual, smaller objects will indicate deeper. Second, the depth scale is really only accurate in pinpoint mode - this important characteristic isn't directly stated in the manual, only implied. These two fundamental qualities are often misunderstood and I think they are the main reason why so many people either get frustrated or simply call the depth meter "inaccurate". The confusion for a new user is certainly understandable - as you said, you swing over the target, and it says 6-8", pinpoint mode says 4", and out pops a bit of copper wire barely 2" down...what the?!?

Basically, I ignore the depth indicator when sweeping a target - that's where the proportional audio will give you a better initial impression of depth (softer/quieter signals tend to be deeper). But the problem is, proportional audio suffers from the same calibration caveat as pinpoint mode - small, relatively shallow targets will trigger the softer audio while big, deep targets will sound off loud and proud. So, how do you tell what's what?

Personally, I use pinpoint mode’s fixed coin-sized calibration to my advantage - I'll use pinpoint mode to "x mark the spot" and note depth, but then I lift the coil a couple inches to pinpoint and note the depth again. Here's what happens...if the target is coin sized, and I lift the coil 2", the depth indication should increase by 2". If the target is noticeably larger than coin sized but deep, lifting the coil a couple or even a few inches won't impact the depth indication at all – you might even need to lift the coil half a foot or more before the depth indication changes! Lifting the coil this way literally only takes an extra second or two, but will save you buckets of time compared to the long minutes you might otherwise spend digging 10" down just to recover a rusty, cell phone sized steel plate that rang up in the upper 80s and indicated 4" down. If the target is small and shallow, lifting the coil should cause too large of a change in corresponding depth indication - but honestly, for some reason, that seems a little harder to notice. To guard against the shallow stuff fooling me, whenever I think I have a coin sized target, I cut the plug then sweep the hole and plug with my handheld pinpointer. If no joy at that point, I do a quick sweep with the detector to confirm whether it's in the plug or in the hole before I resume digging.

Call Me V said:

I've been learning to listen to signals, but I'm still unsure of what I hear, so I tend to look at all the info on the screen to help me determine what and how to dig.

Click to expand...

Just like you mentioned, I also still tend to watch my screen pretty closely - maybe that’ll change as I gain more experience, but for now, as a second year detectorist, I feel that the VDI provides too much important information that tone alone can't give me on the Garretts I've used. I scratch my head a little when folks suggest that with experience you can tell a quarter from a dime just by the tone - maybe that's true on a machine with 50 tones, but with the AT and Ace series, a high tone is a high tone. 88 doesn't sound any different than 81 to my ears. But I guess for high tones, it doesn't matter so much - if the depth/size seems right, I'm usually digging a high tone. But for mid-tones, I don't see how you can decide to dig or not without evaluating what the VDI has to say.

I don't pay a lot of attention to the "inches." It has been my experience with my detector that those are just suggestions. I sort of read the depth scale as not very deep, shouldn't be too hard to dig up, and way down there. I get along a lot better with those less precise indicators. It works for me.