I Need help with GTI 2500?

[TC-NM]

I need help with my GTI 2500. I use the 5 x 10 dd coil (non-imaging coil), sensitivity set 5 to 6 (not the default of 9) and switch back from Coins to Zero and sometimes my custom settings, in DISC mode. The problem is when I hunt in city parks, there is the usual trash. Now correct me if I'm wrong but, steel bottle caps register 1.5 to 2 on the GTA and all U.S. coins register from 8 to12.

A while ago I hunted a park where I was getting some descent finds, but what was discouraging was it showed me on the GTA that more than half of my readings were at 10 to 10.5 or another words a $.50 piece. When I dug it up, it was a bottle cap. Another 10.5 reading and yet another bottle cap Some of these bottle caps were new to a couple of months to even a couple of years old. This has been consistently happening. My machine has been very stable hunting here in NM and has not been upgraded with the new mineralization chip. So what gives?

Anyone out there had this happen to them where you live

TC-NM

 

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[shibumi]

The same thing happens to me and I live in MN. I have found that pennies will come in at 6 and 7 and some of those at that range are indianhead and wheats. I found a 14k gold ring at four inchs it rang in at 6 on the display. when I hunt it is coin mode or custom. Custom mode I have set for 4 and up some of the nickels and pennies will bounce around from all the way to 8 or 9. The sensitivity I set from 5.5 to 7.5 anything above that and it never seems to work well for me. The ground up here is highly mineralized. I find that I have to moved the sensitivity around alot but lately 6.5 has been working the best. That gold ring I found sounded like an indian head penny to me. Today I was in wisconsin and found a 1907 dime and surprisingly it sounded like a penny not a silver dime. I think the minerals in the soil play the biggest part in how it reads and sounds. So far I have hunted in MN, WI, IA, and ND most of the time coins do register and sound the way they should but not always. This is just what I have notice others will have more insight but I hope this helps some.

 

[John-Edmonton]

Bottle caps are funny things. They can read as a bottle cap, or right up where the coins are. It depends how much oxidation (rust) has formed, their horizontal positioning, and some of those old ones with the aluminum disk on them facing up will also give a coin reading. And they are not all equal. They can have different metal composition also. The metal detector is only reporting what it is seeing.

Now for the good news. Got an iffy signal? Bottle cap or coin as it just doesn't bang as hard? Here's what you do. The next time you have such a signal, stamp your foot HARD over the target. If it is a rusty bottle cap, you will have disturbed the formed halo and they will now read at the left part of the screen and show as junk, or just bounce around the screen also indicating junk. If not, dig it and you might just pull out a large cent, IH or other surprise. Try this....it really works.

 

[TC-NM]

Everyone,

Even if the bottlecaps are steel and quite possibly other alloys combined in the cap, 9 times out of 10 will read as 10 to 10.5 on the GTA? Well I thought that C. Garrett and his engineers have designed the GTI (their flagship) and tested out their machines thoroughly I suppose this is the nature of the ('lil green) beast due, not to mention the fact of 1997-99 technology.

I know that the conductivity of metals, especially aluminum ranks Number One and Gold, number two, brass/bronze rank three and four and so-forth. It's somewhat discouraging to say the least.

Thanks for the insight and to you John for the hunting tips.

TC-NM

 

[John-Edmonton]

Everyone,

Even if the bottlecaps are steel and quite possibly other alloys combined in the cap, 9 times out of 10 will read as 10 to 10.5 on the GTA? Well I thought that C. Garrett and his engineers have designed the GTI (their flagship) and tested out their machines thoroughly I suppose this is the nature of the ('lil green) beast due, not to mention the fact of 1997-99 technology.

I know that the conductivity of metals, especially aluminum ranks Number One and Gold, number two, brass/bronze rank three and four and so-forth. It's somewhat discouraging to say the least.

Thanks for the insight and to you John for the hunting tips.

TC-NM

All "DD" coils are hot on bottlecaps and often read them as good targets. It's like that on other manufacturers too! DD's give you extra depth in difficult soil, but you lose a little discrimination quality. Concentric coils give better ID characteristics. Both types = about the same depth in neutral soil.

Below is a link to an article on coils you might find of interest:

http://www.garrett.com/hobby/techsupport/techsheets/searchcoil.pdf

 

[Eu_citzen]

Hello, I had no problem with bottlecaps but with nails that rang up in the upper "gold range".
And just as John said composition, form, size etc will change a reading.

So the best thing to say is that the disc is not often perfect.

 

[lgadbois]

You won't find as much if you don't dig everything! Coins and jewelry can be hidden to a detector if they are surrounded by junk.

Discrimination is a complex science. The conductivity is only a part of the analysis. The magnetic properties of metals are used to identify the type of metal. An object containing iron will cause the inductive reactance of a coil to increase. Aluminum will cause the reactance to decrease. Each metal has it's own properties, and alloys may add or subtract from the effect that will be rendered by a pure metal.

Only experience will tell you what discrimination settings work best in various detecting environments.

 

[Eu_citzen]

It is correct that you need to dig everything to not miss anything good but in a very trashy site that is simply not practical.

 

[dan_h]

Playing the Percentages. I think Andy Sabisch used that expression in one of his columns. You have limited time and digging every signal is time consuming so you lose something when you have to end a session not having scanned as much area as you had wanted to do. It's a judgment call. If you find a few old coins, it would pay to dig everything. But if it's a modern site such "attention to detail" might not be warranted. I don't mind digging junk if I know ahead of time that's what it probably is. I don't find it so disappointing if I'm alerted before digging, to expect junk, so I like the meter of my GTI1500.

 

[panelman]

TC
I have had a 2500 since spring ($128.00 clad 15 silver coins, bit of jewlery) and have had similar problems! What I do if the signal is iffy and a bit deeper 4" + I will always cut the sod cap off and swing on it again. I find alot of times the signal will change to the bottle cap range. If its still strong I will dig it and yes sometimes it sill can be a cap but not that often. I liked Johns suggestion of stomping the ground, I'm going to try that technique tonight.

 

[Eu_citzen]

Stomping works, I have used that since I started.