Signal issues GB?

#1
I'm fairly new to the GTI 2500 and being used to my Whites TDI it's a new ballgame. The past 2 outings I was getting 25cent signals and dug up everything from nuts, nails, pennies and other trash. I put a quarter on the ground and it read a crisp 25cents. I then pulled up a plug, threw the quarter in, put the plug in and didn't even get a signal. We're talkin' 6 inches here! I reset the machine prior to hunting so it's (supposedly) back to factory settings. My question is do I need to manually GB the machine? I was under the impression it's a "turn on and go" machine. Please bear with me, I normally use a Whites TDI.
 

steve07

Well-Known Member
#3
Welcome Aboard

to TQ Pickpan!!! Sorry I can't help either. Hopefully drawing more attention to your post may get someone who knows to look.
Glad you are signed in here though!!!!
 

Company F

Well-Known Member
#4
Find a Garrett forum online and ask someone experienced with the GTI about the problems you have encountered. You can locate one by going to a search engine such as Yahoo or Google. I'm sure someone will jump in and help. I use a White's MXT and not qualified to answer your question. :spin:
 

Jason in Enid

Well-Known Member
#9
It could be that your Garrett is working just fine.

Your detector could be adjusting for heavy mineralization like it was designed to do, and a freshly planted quarter might not be able to respond above the background "noise". It has been known for a long time that fresh plants NEVER sound off like "real" targets. When a metal is in the ground for years, it develops a halo of oxidation around it. Same thing that makes iron false to a detector helps it find copper and silver.
 
#10
It could be that your Garrett is working just fine.

Your detector could be adjusting for heavy mineralization like it was designed to do, and a freshly planted quarter might not be able to respond above the background "noise". It has been known for a long time that fresh plants NEVER sound off like "real" targets. When a metal is in the ground for years, it develops a halo of oxidation around it. Same thing that makes iron false to a detector helps it find copper and silver.
Thanks Jason :bthumb: That's interesting. Can you point me to some info regarding this halo effect?
 

Jason in Enid

Well-Known Member
#11
Well, I've never read a scientific report on the phenomenom. It's basically what detectorists have discovered in the course 50+ years of metal detecting.

Observations... When you dig metal (any metal) look at the soil immediately surrounding it. Iron is surrounded by rust. Copper is surrounded with "green". Coins get discolored because they are reacting with the ground around them.

Ground conditions... When ground is wet, the halo spreads and deeper coins can be found. When the ground is dry, the halo shrinks and coins can be found that used to be hidden by close iron.

Time... It has been noticed a long time ago that freshly buried coins can be very hard to find. Come back next year and you can probably find it.

Discrimination. Wave a common iron target like a nail or small piece of scrap iron under a coil and your machine will accurately discriminate it. Even a rusty iron will be discriminated. Put that iron in the ground for a while and your machine will start having trouble ignoring it.
 

steve07

Well-Known Member
#14
Very Good!!!

Well, I've never read a scientific report on the phenomenom. It's basically what detectorists have discovered in the course 50+ years of metal detecting.

Observations... When you dig metal (any metal) look at the soil immediately surrounding it. Iron is surrounded by rust. Copper is surrounded with "green". Coins get discolored because they are reacting with the ground around them.

Ground conditions... When ground is wet, the halo spreads and deeper coins can be found. When the ground is dry, the halo shrinks and coins can be found that used to be hidden by close iron.

Time... It has been noticed a long time ago that freshly buried coins can be very hard to find. Come back next year and you can probably find it.

Discrimination. Wave a common iron target like a nail or small piece of scrap iron under a coil and your machine will accurately discriminate it. Even a rusty iron will be discriminated. Put that iron in the ground for a while and your machine will start having trouble ignoring it.
Jason you gave a good explanation, I just added the links for more info!!!
 
#17
What I have seen with my GTI 2500

Hi Pickpan, I am a GTI 2500 user for about a year now. I just found this forum so I will try to help. You did not say what mode you were in when you were getting a solid 25 cents. All metal mode, coin shooter, Jewry, Relic. Knowing that would help me to help you. I like to run my GTI 2500 either in all metal mode or zero discriminate. I have my audio set up with the bell tone turned on and bi tone turned on. With this audio setting set this way if you don’t get the bell tone when scanning over something 99% of the time it is not a coin. I have never gotten the bell tone and not found a coin. The scale only shows what the conductivity of the object is. So if you get a soiled bell tone in all directions and it is showing a quarter it is a quarter. I mostly use a 7X10 DD from Garrett. This is not an imaging coil but I can get just about the same amount of information when I use this DD coil in other ways. As you scan you can see how big the target is by scanning it in imaging mode, as you scan see how large the signal is. If it is not small it’s not a coin. This coil is much lighter to swing all day long. It’s true that you can bury a coin at 6 “ and not see it. Come bake in a year and you will. Try this with an air test see how close the quarter needs to be to see it. Most likely you won’t see the coin at 6” or close to it anyway. I have found coins at 8” in the past in zero discrimination, and I have found other items up to 13” in all metal mode with my GTI. The only time you need to ground balance is when you are hunting in all metal mode. If you are not in a highly mineralized ground set the speed that auto track changes to slow. If you are in highly mineralized ground that changes often you may need to speed up how fast auto track changes to account for the mineralization. The only time I really use all metals mode is when I’m prospecting for gold or just playing around when coin hunting. I don’t do much relic hunting but this is a very good MD for relic hunting. I think that’s what most people that have this unit use it for. Even though the GTI 2500 set up in audio mode like I said above only gives you 3 different sounds (Belltone,Lowton, highertone) the secret is how loud the sound is. The softer the sound the deeper the target. It take a while to tell the difference, 95% of the time the depth is right on with the Treasure imaging the other 5% it can be off by 1 or 2”. I find this happens mostly with really bad rusted iron. I hope this helps. Take some time to really understand what your MD is telling you and I think you will like it. This is kind of like a turn on and go machine but it’s not a Ace 250 either, it has a lot to offer if you understand its language. I was a little frustrated with it myself when I started using it. It takes time to really understand it. As Mr. Garrett instructs run the MD in Coin mode for at least 10 hours before trying other settings. This will help you understand what it’s telling you better. If you don’t have someone hunting with you that has used this MD you have to learn by what it is telling you and what you find when you dig it up. When I am MD I don’t even look at the LCD until I either get the bell tone or the high tone, Then I look at the scale to see where if falls into the conductivity range. Then I scan in Treasure Imaging to see how large the target is in all directions, If this looks good and I want to dig it, then I look to see who deep the target is, If it is less than 3” I can just pop it out of the ground with a coin probe, if it’s deeper than 3” I have to dig it. Just an FYI if you get a bell tone one way and not another 95% of the time it is just trash the other 5% of the time it is a coin on edge. I have only had a coin on edge 1 time and dug a lot of trash other wise. I know this is long but I hope it helps some.
 
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