New Zealand Gold Prospecting & Metal Detecting Forums Archive

I've noticed a few more AT Pro users out there so thought I would just pass on some tips on getting the most out of it for the new users.

Standard Mode - Forget it!
Don't use it, this mode is just a way of dumbing down a detector that is already easy to use. Its like putting a 80km speed restricter on a V8. Only use Pro Mode. If you are a beginner then the sooner you learn Pro Mode the faster you will get up to speed, don't handicap yourself by taking the "easy" option of Standard.

Notching out for Discrimination. Again forget it!
Yup you will hear all the pull tabs, bits of foil etc but there is nothing wrong with hearing the junk. Notching out works on the VDI of the target, but the problem with this is that sometimes a good find can have the same VDI as a piece of junk. By notching out that VDI you will not hear, see, or notice that the coil has passed over a potential find.

Instead of relying on the number that pops up on the screen, listen to how the target sounds. In Pro Mode the tones can tell you a lot about the target and gives much more information then just a VDI number. The classic example are gold rings - you have probably heard the saying "dig all targets" this is because gold rings can commonly id the same as pull tabs. But in Pro Mode as you pass the coil over a beaver tail pull tab you can hear a longish tone followed by a very short blip (or the other way around depending on the direction of the swing), thus you can be 80% sure it is not a gold ring. I say only 80% sure because an engagement ring with a large gold setting protruding from it can make the same sound, but that's detecting. Also if the beaver tail is folded over then it will be single tone.

But the main problem with Notching is that you remove any possibility of finding a good find that has been masked by a piece of junk. To effectively discriminate by notching you have to remove 2 more notches on either side of the junks VDI, this means that if a good find is beside or below the junk then you will not hear any thing that sounds "suspicious" or different. I find the best setting is Custom with nothing notched out and Iron set to 34. I use this setting for all hunting now.

Pro does not mean Professional
The Pro in AT Pro means Proportional. This refers to the sounds it makes as compared to the single ding of Standard mode or the Ace line. This proportional tone is what makes the AT such a good detector and you should learn to listen to what it is saying. Yes I have already said this in the section above - but it needs reinforcing. For example when hunting in a reasonably clean area and you hear a very faint hollow sounding tone that repeats on each coil swing- dig! This target may not even show up as a VDI on the screen - just a very faint echo sound. When this happens I know that there is a very deep target that the machines processor has ignored because the return signal is too weak. Most of my AT found beach gold has been this sounding target. Learn to listen!

Your AT Pro in the Salt
Again and again I read on forums about how the AT Pro is useless on a salt beach or in the salt water. These posts are always written by those that have never used an AT Pro on the beach! Yes multi-frequency machines are better and will detect deeper but the AT Pro is not far behind at all and I have found some fantastic finds with mine in the salt and these at depths that have amazed me.

BUT the big secret in getting the most out of the AT on the beach is GROUND BALANCE. Yup in caps because GROUND BALANCE means everything to the machines performance. There are 4 zones of a beach where ground balance changes by a drastic amount: The dry sand, the slope between dry and wet sand, the wet sand, under the water. Each of these zones requires redoing the ground balance.

Because of this it is best to work a beach doing each zone separately. I normally zigzag like WWWWW along the dry sand, then do the same to the slope on my return, after that zigzag back along the beach on the wet sand and if getting wet - the same in the water on the return. This saves having to ground balance every few minutes if zigzagging from sand dune to water and back up.

Once you know the beach you soon learn the Ground balance numbers that represent each zone of the beach. This has the advantage that you can quickly manually set the GB when changing zones instead of having to pump the coil.

Don't hesitate to turn down sensitivity
It is so tempting to rev the AT up to full speed and hunt with maximum sensitivity. But you will never need to hunt with all the bars showing- its just not worth it. The sensitivity bars on the AT are not a even scale. For example having half the bars notched out does not mean that you will only get half the depth - instead you will still be getting 75-80% of the maximum depth. This difference reduces as more bars are added and the last couple of bars only make a 1-2% percent difference to the depth of the machine, this is only about 5mm if that.

So there is nothing wrong with turning down sensitivity. Instead use the sensitivity to control any falsing. Falsing to those who don't know is when the detector is ringing up signals that do not repeat with each swing of the coil. Turn up the sensitivity of the AT until you start to get this falsing then turn back down by 2 bars. This will give you maximum depth and the most accurate vdi's and tones.

The Iron Audio button
This can be a pain if on all the time but it is very handy. I normally have it off but if I come across a target that sounds a bit iffy then I will turn it on for a pass of the coil. This is a good way of uncovering those sneaky rusty bottle tops that sometimes ring up as a clear and true tone.

EMI
There are only a few things you can try for reducing Electro Magnetic Interference. First thing is to scroll through the frequency adjustments until you find one that has an effect (Press Pinpoint button then + or - to choice one of the 4 frequencies). This only works sometimes - for example my backyard has high tension powerlines going over the top and F4 works here but on a beach where a faulty air con unit was putting out EMI it has not effect. Next lower sensitivity until the interference reduces, and finally if you can change to a different coil.

Other Tips
Rechargeable batteries are well worth it. I just use Panasonic batteries and a charger that I picked up from Countdown & these have lasted for over 2 years. After each hunt I stick them back onto the charger and leave them there until next time out.

Beware of the battery holder. Because of the design of the AT Pro, when removing the batteries the holder can easily fall out and smash especially if the detector is standing up at the time. But the holders are easily replaced for only a few dollars, Jaycar and similar electronic suppliers hold them in stock. I have also stuck a bit of electrical tape and written UP on one end. This tells me which way around the holder goes in with only a quick glance.

Once every few months I take the shaft apart and give it a good clean out. It is surprising how quickly it can seize up especially if water hunting and sand grains etc are floating around. Unscrew the headphone and coil connectors as well to give a clean. A spray with silicon over the metal parts help avoid corrosion.

Don't scrub the coil when swinging. The coils actually work better and depth is improved if there is a cm or so of air gap between them and the soil, keeping the coil off the ground also avoids scratches or damage. I have gone further and coated the bottom of mine with Plasti-dip since I now mainly hunt over pumice sand which is worse then sand paper.


Ok that's about all I can think off at the moment. If anybody else have any more AT Pro specific hints or tips - lets hear them!

This is a great post for me and i can't thank you both enough.
cheers and beers. at pro learner. 'treeman"

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Edited by user Sunday, 11 August 2013 1:01:18 PM(UTC)  | Reason: Not specified

Great info Shilo. One day i invision myself stepping up to an At Pro or Gold. I like your theory on hunting all metal mode so you know/and can hear what is down there. Only in this mode will you get a true reading of what is under the ground.
Anyhows, Im looking forward to my first go on one.

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haha Im hoping the good gold karma remains with this ATpro lol a young jedi i am still!lol.

Thanks for the tips.
so what numbers do you guys dig from? im a bit lazy and only dig 65 and up.

kol thanks for the advise ill go out tomorrow and start digging some lower targets. The ground is packed with pull tabs, there are targets everywhere.

Nothing wrong with that Andy! Good sh1t!

hahaha poached ya town mate ol!cheers!

You got off easy! :)

Land hunting is always less profitable for gold then a beach because the light targets are not sorted from the heavy items, thus you will dig a lot more junk before finding gold. Gold can vary enormously with its VDI right from the low 40's (or even below in the case of chains) up to the mid - high 60's. A lot will be around the same as pull tabs and since modern pull tabs sound so clear you have to dig them to find gold. Another large proportion of the gold I have found is in the same range as an old 20c piece so I never pass up digging those as well.

Unfortunately the hard yards have to be done to find the riches, but your brain will soon tell you "that is most likely a pull tab" or "that sounds like a pull tab but something about it is different" If I think there is a slight difference then I dig just in case. Also the old style pull tabs with the ring and tongue can make a distinctive sound with the AT Pro - you will hear a clear tone then a slight "tick" if you sweep it from different directions. This is the coil sounding off on the ring then picking up the tongue, because the 2 parts are so close and joined it almost sounds like one solid signal but with a slight difference. Of course I have found a 18ct diamond solitaire ring that sounds off the same but 999 out of 1000 it will be an old pull tab.

By the way the above only works by using Pro Mode, forget that Standard even exists on the machine and stick to Pro. Digging all solid or good sounding targets is really the only way of learning to hear any difference between junk and good finds.

Edited by user Tuesday, 24 September 2013 2:36:51 PM(UTC)  | Reason: Not specified