Discriminator setup should be done where you are going to hunt. If you are unfamiliar with the site then set to all metal and walk through the area to get an idea about how much metal trash is in the area. If the area is littered with pulltabs, bottlecaps, foil, and rusty objects then it is a good idea to use your smallest coil. Only the small coil will be able to locate coins in so much trash. Settings and tips are defined in large part by the soil in which we hunt and I believe that no standard setting will work in every soil condition. Even if you do not use this type of detector you may gain insight into soil settings for yours.
Soil conditions in the town where I live are mostly impervious clay. This is heavy dark clay which has the tendency to hold water for some time without draining. You might not think that a coin would sink very far into such a soil but I have found late date clad quarters at six inches deep. The most important thing about a detector setting is unless you know exactly what to expect at a given site it is better to wait until you get there before setting your machine. The thing that I like about this detector is the very nice way in which you can selectively notch out pulltabs for instance while including everything below and above pulltabs on the meter. I have not noticed as much depth loss by using a lot of discrimination as occurs in some detectors.
COINS IN VERY TRASHY AREAS: where a dozen objects may lie under your coil the large coil size will mask out coins that may be detected with a small coil. In areas like this I prefer to search only for coins instead of digging everything and I notch out even nickles which are often confused with soda can pulls. The only thing that I usually notch on is dimes through halfs. You might wonder why I notch out dollars and this trick was told to me by my friend Tony who discovered that the GTA will go bonkers around metal bars or fences and since we have no more dollars around here I can take out the dollar and the detector works in close to these objects without giving you all of the extra free signals. This way I can pull out coins out of such intense metal trash that most hunters just give up. Using this trick you can detect under metal stadiums even very close to the seats and still find coins but turn boost off
RINGS IN LOW TO MODERATE TRASH: Notch off everything left of the AP in bottlecap since many of the wedding rings show up under AP to Nickle and notch on AP through Half. The class rings may show up everywhere from nickle to penny on the scale. Silver rings generally show up as half dollars. I do not look for rings everywhere but try to locate areas where people are more likely to lose rings before I dig everything.
TINY JEWELRY IN DRY SAND: Notch on everything with the possible exception of iron (far left notch) and use the 8 inch coil with the sensitivity turned all of the way up (if you can) I do not use boost because of extra battery drain unless I have a very tiny signal that I am trying to locate. Listen for ANY tiny click as you swing the coil and NEVER go away without digging it up. Diamond earrings may be very small and difficult to locate in dry sand. Often the smallest signal is the best treasure.
TRICK#1: Hold pinpoint down. The GTA1000 is a very sensitive no motion detector in this setting and you can find the deepest finds. I wish Mr. Garrett made this detector with a toggle pinpoint. Pinpoint will tell you when you cross a target just how large the target is. I use this to indicate when the ID shows penny or dime and is a tin can by passing over the target and noticing the sharpness of the tone and how far it will signal away from the target. Often a buried tin can will indicate a penny on top of the ground and you can lift the coil an inch or two and notice wether it still shows the coin on top. There is no need to dig tin cans because they can be detected easy if we don’t get lazy and try to dig everything.
BEACH HUNTING: I assumed that the beach mode setting was just one more preset that I could program better on mode C on my programmable mode. It is not! Garrett actually has a salt rejection feature in this mode that works better close to the water on a salt beach. This is not advertised but apparently works. I tried using it near the water and my program chattered a lot in this area but beach mode worked better. I added some notches from the AP to nickle to pick up wedding rings and it still seemed to work better. I got a signal at the waters edge the other day and dug a hole 1 foot deep with my small digger and did not reach it so I know it is picking up deep also. I use the pinpoint trick at the beach also to detect very small jewelry but it does not work in the water but only in dry sand. When I find a stretch of beach where there are a lot of coins then I look harder for jewelry because I assume that either more people have used this area or the other treasure hunters have not tried it.
HUNTING IN WET GRASS: If you have a coil cover on your detector you should know that it will begin to give you extra belltones every swing if the cover gets full of water. In conditions like these either take off the cover or use silicon lubricant around the opening to prevent water from seeping into the cover. Carry a towel with you to set the detector on instead of the wet grass because the speaker is under the battery pack and open to damage.
SIGNALS THAT COME AND GO: Use last mode set on all metal to toggle when you get weak signals because the signal may be a little stronger in the all metal mode than in discriminate mode. Many of these signals may come from deeply buried coins and depending on the age of the area you are hunting should be dug.
Take great care with the meter face because the LCD’s can be damaged easy with your digging tool. Keep the wire tightly wound because this can send false signals and the connector screwed on tight.
Audio boost seems to work better when it is looking for larger metal targets than small ones. The GTA will pick up a large target a considerable distance in boost mode and I believe that the 12 inch coil would be super looking for relics or cache targets.
UPDATE: When you receive a beltone that you have a solid target and then the signal goes away without displaying what the coin was quickly press the REJECT button. This will remove the notch wherever the signal is and you will have a visable display of one of the notches that has been rejected and it will indicate what kind of coin it is. Then press the ACCEPT button to reset the detector. Press pinpoint to view the depth of the coin(it may be very deep) and just dig the prize!