AT Pro Tips, Tricks, and Techniques — New Power from a Decade-Old Detector

If you have any amount of time in the hobby of metal detecting, and possibly if you are a novice or don’t detect at all, the chances of having heard of Garrett metal detectors is pretty high.  If so, probably no other detector since Eleanor and Charles Garrett establish their business April 1, 1964, has captured the interest and respect that the AT series of detectors has and in particular the AT Pro™.  The AT Pro was released in 2010 and was first introduced with KG and Ringy on the TV series “Diggers” (2012-2013). Despite the fact it is a decade-old detector, it still remains an amazing machine in the hands of about anyone.  It is an intuitive turn and go machine in a beginning detectorist’s hands, and a scalpel like instrument in the hands of an intermediate and advanced detectorist.

With last year’s introduction of Garrett’s ACE Apex™, and the recent release of the successor to XP’s flagship Deus™, the Deus II™, as well as Nokta Makro’s soon-to-be shipping Legend™ detector technology has changed a bit since AT Pro’s groundbreaking introduction.  Both of these machines are following suit with Minelab’s fan-favorite Equinox’s boasting simultaneous multi-frequency technologies.  Let’s not forget Fisher Labs’ newer machines like the F19, F22, and F44 which have added things like better ferrous target discrimination and the FeTone™ iron audio. 

You might be asking why not upgrade considering the innovations to detector technology since the introduction of the AT Pro?  Wait, not so fast, there are many day-to-day detectorists and detecting influencers out there who have not switched and don’t plan to any time soon, regardless of the newer machines and technology. They have grown so competent with the AT series that it is almost like an extension of their own arms.  They’ve learned to milk the AT Pro in particular for all the capabilities it possesses and I will attempt here to expose some of the lesser know tips, tricks, and techniques used to do that.

Go Deeper

Do you have a field, park, front yard you are hunting and the targets are just not there like you want or do the targets seem to have faint audio response?  Do you get the feeling they are deeper and more importantly is there little to no trash or iron on-site and you just need to squeak a bit more signal strength out of the Pro? In that case try:

Zero Mode (All-Metal on ATMax™ and ATGold™)

• Ground balance your machine (see next section Trick the Coil for more info.).
• Set IRON DISC level (I like to discriminate anything 35 and below, so I set at 35).
• Dial in your normal comfortable settings on “Custom Mode”, sensitivity, discrimination, IRON AUDIO (note you don’t have threshold with the Pro but you can adjust this on the Max and Gold.
• Then switch over to “All Metal Mode” pressing the “Mode” button.

This will open things wide open and will give you one tone for every target, but it hits the targets just a little harder for those that are faint and deep.  You can look at your VDI numbers and decide if you want to dig or not, you can also quickly switch to your “Custom” Mode you have set up and compare the signal and tones if you like.  This method and mode use can seem annoying at first but try to dig anything from between 50 and 95/96 and you will not be disappointed. Relics (especially military buttons, pewter items, smaller copper items, spoons) tend to hover around the 50s into the 60s well below coin VDI’s.  Gold hides in those numbers often as well.

Trick the Coil

Ground balance essentially is a technology-based way to trick the coil and neutralize the effect of minerals in a given soil. This effectively is quieting the machine’s response to those minerals as much as possible, in essence tricking it to ignore the minerals and let a target be heard more clearly.  If you ground balance and the G.B. number is closer to the 90s your ground has more ferrous mineralization, if closer to 0 it has more conductive or non-ferrous mineralization.  The idea here is to get the AT’s response to the ground to be closer to neutral, to see the rose in a field of mineralization “thorns” more easily or in other words eliminate background chatter to make a target standout.

Garrett AT Pro Interface
Yellow bubble shows the GND BAL or “G.B.” button and NOTCH DISC “-” AND “+” button locations.

I am often surprised by how many people, even seasoned detectorists, neglect the versatile ground balance options available on the AT Pro to accomplish this.  The AT Pro can be balanced in the following ways:

Automatic (with pumping) – by depressing and holding the ground balance (G.B.) button and pumping (and this is critical) the coil at the height you will be swinging, as close to the ground as possible. Pump in a travel range of motion of 1” to 2” pump is all you want to do.  You aren’t trying to look like you are doing a full push up with your detector in hand in other words. Do this until all chatter/noise disappears (or as much as possible) then release the G.B. button.

Manual (with pumping) – quick press the G.B. button and pump as above, while pumping if low tones are heard increase with “+” NOTCH DISC button, and if high tones are heard decrease with the “-” NOTCH DISC button and then quick press the G.B. button again when chatter/noise disappears (or as much as possible).

Manual (no pumping) – after using either of the methods above you can further adjust the G.B. for certain situations.  You may want to move it upwards (ground balance “+”) to increase detection of smaller nonferrous targets, or lower (ground balance “-”) to decrease detection of low conductive hot rocks, coal, slag, etc. To do this quick press the ground balance then press the NOTCH DISC “+” or “-” buttons however many you need then press the G.B. button again.

PRO TIP – The “Ten Over / Ten Under” Technique (trick):

Many times you can actually increase the detection of high conductors like silver and copper coins by manually adjusting from the number you’ve arrived at using the methods above by 7-10 lower.       You can also increase detection of low conductors (mainly gold) by adjusting 7-10 higher. 

This is best used on a target “quiet” site that the ground balancing was not crazy, to begin with.  If you don’t mind the chatter that the lowering or raising of the G.B. number can cause, you can learn to pull silver through a bed of nails so to speak using this technique.  You do need to be hyper-focused listening to the tones, however. You may have to adjust the sensitivity up or down a bit as well.  If you feel a site has been hammered try this some time, you will be happily surprised more times than not.

Notching

Yes, the AT Pro has a very simple WYSIWYG (What You See Is What You Get) notching interface.  Press the NOTCH DISC “-” (left) or “+” right buttons to move the black box “Target ID Cursor” over the VID range pixel and then press the ELIM button to either unmark that pixel or remark it and it is notched out (removed) or in (added).  You can do this while in CUSTOM mode to set up a range for a particular site.

What many people don’t use it for is finding the same signal or in some cases NOT finding the same signal multiple times.

Scenario 1:  You show up to find Grandma Smith’s earring she just knows she’s lost in the front yard how can you narrow down the signal you are looking for especially when grandpa spent years throwing pull tabs in the front yard?

Solution:   Grandma, fortunately, still has the other earring of the pair.  Simply place that one on the ground (or in the ground if she doesn’t mind and it’s been lost a while) and swing over this target repeatedly after having already set up the machine, ground balancing, etc.  Make note of the VDI number you get, then all you have to do is “notch out” every other VDI pixel but the one indicating the ear ring’s VDI you noted.  This real narrows the amount of targets you dig in grandma’s yard and theoretically will help you find the missing earring much better.  If you cover an area with no luck you may choose to notch back in the pixel either side of the target number.

Scenario 2:  You are on a site that has great targets but you keep digging old canning jar lids that just have to be coins, you think.  Their VDI numbers is landing between 88 to 89 and you don’t want to dig any more of those today.

Solution:  Just notch 88 or 89 as detailed above out and go back to swinging.

Garrett AT Pro Interface
Yellow bubbles show the Target ID Cursor/VDI range pixels (top) and  NOTCH DISC “-” AND “+” button locations (below).

PRO TIP – The “Needle in the haystack” technique (trick):

Often I’ve been hunting an old home site in a field which has yielded multiple coins but parts of it had just a load of new trash (mostly aluminum). I thought “but there just has to be more coins hiding in there somewhere”.  Never fear, the AT Pro can find the needle in the haystack, you just may need to narrow your focus a bit and pick what you are hunting for.  Instead of running the settings of the AT Pro wide open, notch out all the numbers either side of a known good target VDI.  Maybe aluminum is coming in with a wide range of VDI’s from 86 to 90 but you know there are Indian Head Cents there that always seem to ring up with a VDI of 75. Notch out everything but 75 or a range of numbers of good known targets and get to swinging. I’ve done this several times with great results.  It can be even more effective when used in conjunction with a smaller coil.

Day at the Beach

The AT Pro was one of the first mainstream machines to be equally at home on land as well as in the water (its name actually stands for All Terrain Proportional sound or AT Pro).  You will want to deviate a bit from the standard settings when hunting saltwater beaches and shallow waters:

Garrett AT Pro Beach Settings: Dry Sand

• Pro mode
• Iron discrimination: set higher somewhere around 30.
• Sensitivity:  7-8 (max)
• Ground balance once you are on the beach sand.

You tend to be able to get deeper in this sand generally being lower in mineralization (this will vary by location so experiment with this.  You will get more chatter/crackle while in Pro mode.  Setting discrimination at 30 you’ll dig more foil but often times gold and platinum rings would be missed if it were set at max discrimination. May need to rebalance once moving into wetter sands and inherently more mineralized soils often due to black sands below tidal sands.

Garrett AT Pro Beach Settings: Wet Sand

• Pro mode
• Iron discrimination: 0 to 30.
• Sensitivity:  5-8 (you may need to back down the sensitivity based on mineralization in sand)
• Ground balance every time you move location (dry to wet or wet to dry).

You can and should lower the discrimination as much as you can handle due to the fact there are often fewer targets once you move out into the wet sands and you may not want to miss targets here.

Ground balancing more often in the wet sand is often necessary because the wet sands are often inherently more mineralized soils often due to black sands hiding below tidal sands. Sensitivity may need to be adjusted down if chatter becomes unbearable here.

The Simple Things

The following might seem like beginner tips but often even intermediate users of the AT Pro forget about these things from time to time. We all tend to get into autopilot mode after using this machine for years, then turning it on and running into the field and occasionally have to stop a moment and think…now how do I do that again?

Too Much Noise

Is your machine suddenly erratic?  Did you just grab the machine and turn it on setting on the ground next to your car parked under some power lines and suddenly your ears are blowing out from loud constant signal even after you’ve walked away from the vehicle?  What I describe here is the perfect storm really.

It is best practice to start your AT Pro away from large metal targets (in this case your car, again I know this is basic) and away from sources of EMI (power lines).  I also typically do my power on with the coil off the ground, then do my ground balancing with coil just above the ground in an area clear of targets (quick sweep or pinpoint area holding PINPOINT button down)

1. Factory Reset:  The very first thing you should do if this does not clear things up is do a RESET.  Press the Power button in for a 5 count (5 seconds) and you will hear a quick double beep.  This generally clears this issue MOST of the time.
2. If not, check your coil cable connection, pull your coil cover and clean out any sand left over from other hunts…especially beach hunts. 
3. After you’ve done these things adjust your frequency and sensitivity if you suspect EMI from the power lines.
4. To adjust your Frequency simply press and hold your PINPOINT button while simultaneously pressing the SENSITIVITY “+” or “-” buttons and cycle through the 4 settings F1-F4.  Do this until the chatter ends or is cut to comfortable levels.  Incidentally use this frequency shift if you are hunting next to friends using other machines like the EQUINOX or the DEUS both tend to cause erratic signal noise on the AT Pro.
5. IF none of these methods work, try changing the batteries.  Did you throw in some cheap dollar store batteries or recyclable batteries? Both do not play well quite often with the AT Pro.

I am not going to go into pinpointing here as numerous videos, articles, and trains of thought exist as to how to best pinpoint with the AT Pro and it is a bit different with each coil used.

Lastly, slow down your swing if signals seem “iffy”.  When pinpointing such a target if it has a clear non-ferrous tone with a small pinpoint profile (short sweep width) and the depth is 8” or more I typically dig that.  If the pinpoint profile is wide and the depth is 8” or more I do not.  In this case, it is usually a large piece of iron, or sheet metal of some kind, or even a buried car.  I call this the “tip of the iceberg” concept.  If it bounces between non-ferrous and Iron grunts at that depth I often dig it, it could be a brass crotal bell with an iron clapper inside, or other ferrous/nonferrous combination relic.  Remember, if in doubt, dig it.

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Hopefully, these tips and tricks you can put into use and get some renewed life out of your AT Pro a machine far ahead of its time.  In capable hands, it still has a lot of treasure hunting life left in it!