AT Pro Ground Balance

[fuzymunky]

Just read an article that said quote: "With Grnd Bal on '0'..... the unit is much more sensitive to high conductors (copper/silver coins)..............and gold-dead. With Grnd Bal on '99'...... this unit is substantially detuned to high conductors (copper/silver coins); yet, is extremely sensitive to low conductors such as very small gold jewelry."

If this guy's article is true, could that be the reason for my problem with silver coins? This is how I Grnd Bal: I hold the button and gently "pump" the unit up and down (~6-7" up, ~1/2-1" down). What I've noticed is this: High mineral ground (which is about all we have here in CO) I will hear the low tone of the unit trying to balance, coupled with a somewhat faint high tone resembling that of a "good target" tone. This results in a balance in the mid 80s. Ground with little to no mineral, the low tone of the balancing only, and unit will balance to the low 90s (never seen it go over 93).

I bought this unit from an "authorized" Garrett retail metal detector/prospecting store. Its a very tiny store that would literally be considered 'crowded' with 3-4 customers in it. The guy that showed me "how to use it" was an older man. Said he's got over 30 yrs of MD experience. But he also acted as though his time was extremely 'precious', and while he did offer to give me a "lesson" in using the machine, it lasted all of 5 minutes and he repeatedly interrupted me when I would ask a question. All told, I got to ask zero complete questions.

Anyway, the majority of that 5 minutes was spent on teaching me how to ground balance. He showed me the 'pumping' technique and said that during this process the higher number, the better... So, whenever I've been out swinging, I've strived to obtain the highest Grnd Bal as possible. Is this my problem? If so, how do I fix it? If it was something this simple I swear I'm going to for a week straight.

I've read the manual font to back to front again and watched the DVD that came with it.

Would appreciate any input.

 

[TwistedTig3r]

Here is how I ground balance. First I do a reset. Second I switch to Pro Zero, scan for an area free of metal (no tones). Third I click Ground balance once. Fourth I press and hold ground balance while pumping the machine. It has been my experience that if you get a high a tone during this process, then there is metal under the coil. You are looking for the low hum to slowly fade as the machine becomes "neutral" to ground minerals.
The article is correct based on a "neutral" ground balance and not the literal use of "0" and "99". Meaning if you properly ground balance your machine at say "80" and then manual adjust ground balance to "70" (closer to 0) then you will be "negative" ground balance. Which will make the machine more sensitive to high conductors. If you were then to go from "80" to "90" (closer to 99) you would then be "postive" making the machine more sensitive to low conductors.
My person advice would be to work on a "proper" ground balance and working with the machine. Learn the tones, the vdi is nice but you can often talk yourself out of some great finds. If you hunt public places they may have been picked over in the past, go slow try to grid a section off and hit something that may have been missed in the past. The main thing is have fun dig a bunch of targets and once you hit that silver it will all come together for you.

 

[WV62]

I didn't get a video with my machine so I am not sure what was on yours. The Garrett web site videos was very helpful to me here is the link http://www.garrett.com/hobbysite/hbby_at_pro_videos.aspx I have watched all 7 of them several times.

When I GB I find a clean spot and do the pumping and watch the numbers so lets say I get bounce from 80 to 81 I will try to pump until I can catch the 81 and stop.

Ron in WV

 

[John LA]

Make sure there isn't any metal under the coil and pick a location free of interefence. GB as per the manual. I would leave it there for relics and gold. If you are hunting coins, try this. Bury a few coins at different depths. See how deep you can locate the coins. Manually lower the GB by 10 and check to see if there is an improvement in depth. If there is trying lowering the GB by 10 more and check depth. Doing this you can see for yourself.

 

[BJ in Okla.]

I have 2 AT Pro's and I can change the GB with no problems,, like if GB number is 80,
I can go up or down 10 numbers with no problems,,, yet my friend's AT pro acts up if it goes like 3 numbers from the GB number...
Also my unit will GB at like 80 and the my friends unit will 3 numbers different than mine,,both with the same coil and settings...And on the same spot..
So, if I was you,,I would stay with where the unit GB's at until you get more time on your AT pro...
Good luck,, and get some more time on the AT pro,,and check targets with your friends,,that will help you learn your unit..
Bj

 

[nick hunter]

[size=large]Hi !

What is written in the initial post is quite correct.

GND at 0 will enhance high conductors sensitivity, GND at 99 will be better with low conductors.

I never trust an automatic ground balance, and do it always manually, trying to find the best compromise between what I want to find and the reality of ground conditions.

A machine does not think.

We all do.

HH

Nick

 

[Sailorman]

Ground balance in fairly neutral soil isn't really necessary. It's done to keep the machine from falsing on minerals in the soil. In fact if there are no minerals to deal with the auto function won't even work. Then, yes, you can set it to whatever suits your fancy. One place you'll see that really fast is a saltwater beach or mineral spring, then it's critical. Shifting the numbers manually up or down ten points can shift performance a little in your favor for high or low conductors. Watch the Garrett videos, learn the Pro Audio sounds. Then get your coil over silver and it'll tell you. The AT-Pro might miss a few of the deepest ones compared to machines that cost two to three times more but the depth difference is only a small amount especially considering the cost differential.

Experience on a machine matters and that comes with time and then there's picking the right spot and a certain degree of plain ol' dumb luck.

I can put you on a few spots in neutral soil FL that are so hot that if you don't have the ground balance right the machine will just be crazy and miss any target you cross. Get it just right and the goods appear.

 

[BJ in Okla.]

Depending on what you are looking for,,,0 & 99 ?????
About 10 numbers is all I can do,, up or down,,, and my friends unit will only do like 3 numbers up or down....
Not all AT Pro units are the same...
8o is the factory preset..
I talked to Sue at Garrett,, and she told me,, she sets hers at 80 and hunts.....
Every place that I have hunted,,, I can run Max sens.....Some run 2 bars down,and never use Max Sens, Sue for one...
At what GB does iron start sounding better ???
Bj

 

[fuzymunky]

Ground balance in fairly neutral soil isn't really necessary. It's done to keep the machine from falsing on minerals in the soil. In fact if there are no minerals to deal with the auto function won't even work. Then, yes, you can set it to whatever suits your fancy. One place you'll see that really fast is a saltwater beach or mineral spring, then it's critical. Shifting the numbers manually up or down ten points can shift performance a little in your favor for high or low conductors. Watch the Garrett videos, learn the Pro Audio sounds. Then get your coil over silver and it'll tell you. The AT-Pro might miss a few of the deepest ones compared to machines that cost two to three times more but the depth difference is only a small amount especially considering the cost differential.

Experience on a machine matters and that comes with time and then there's picking the right spot and a certain degree of plain ol' dumb luck.

I can put you on a few spots in neutral soil FL that are so hot that if you don't have the ground balance right the machine will just be crazy and miss any target you cross. Get it just right and the goods appear.

We have the exact opposite problem. Colorado soil is highly mineralized.

 

[Sailorman]

That's the point. You have hot ground so your ground balance is important to get right. Just like our mineral springs which are extremely mineralised. You can't just pick a number based on what you're looking for in ground like that.

 

[nick hunter]

Depending on what you are looking for,,,0 & 99 ?????
About 10 numbers is all I can do,, up or down,,, and my friends unit will only do like 3 numbers up or down....
Not all AT Pro units are the same...
8o is the factory preset..
I talked to Sue at Garrett,, and she told me,, she sets hers at 80 and hunts.....
Every place that I have hunted,,, I can run Max sens.....Some run 2 bars down,and never use Max Sens, Sue for one...
At what GB does iron start sounding better ???
Bj

Nono, the closest i can get towards these numbers. Beach hunter here. I am quite convinced that the AT PRO would find more gold inland with the sniper coil, iron open from 30 up, default GB setting of 80 and sensitivity at 6 notches.

These settings are standard for a successful gold jewelry detector : the Compadre.

No reasons not to mimic it with the AT pro.

HH

Nick

 

[fuzymunky]

That's the point. You have hot ground so your ground balance is important to get right. Just like our mineral springs which are extremely mineralised. You can't just pick a number based on what you're looking for in ground like that.

I guess I'm missing your point.

I don't remember saying I was just picking a number to hunt with. As a matter of fact what I did say was that I use the auto ground balance (by holding the button and pumping). My inquiry was whether I'm having the silver problem that exists due to just auto balancing and if so, what range experience people have had +/- in high mineral ground.

 

[firstring]

My inquiry was whether I'm having the silver problem that exists due to just auto balancing

No

 

[marcomo]

Ground balancing (inland, with no salt in the equation) essentially is filtering decomposed iron so the detector runs smoothly. But filtering out that iron also decreases depth. Which is why you can find targets so much deeper in inert soil.

The AT Pro is so stable that in many areas I can get maximum silver depth by lowering the GB 5-20 notches with full sensitivity and still run the detector with sufficient stability.

fuzymunky, I would guess what you refer to as your problem with silver has a lot to do with the fact that there is less siver in the ground all the time. If you are hunting public places, keep in mind that there have probably been a lot of detectors that have swung over it before you.

No site is ever hunted out, but public silver gets scarcer all the time. It ain't being replaced...

One thing I'd suggest the next time you buy anything detecting related, fuzymunky, is ditch that dealer you bought the AT from like the plague. That guy made you feel like you were a bother, and that's no way to treat a customer. I promise you there are a lot of great dealers who advertise on this forum who are friendly will spend as much time with you as you need. I use Chuck at Indian Nations a lot, but you can tell if you look at the feedback that just abouit any of the sponsors here will give you great and friendly service.