eliminating iron signals

When a detector discriminates a target it causes what is called nulling. This nulling effect can mask other targets. depending on you processor speed in your detector you could miss a good target. You can test the effect by placing a nail on the ground next to a quarter with your iron mask on. The other thing that can mask a target is your detectors recovery speed if you have the iron mask off or in all metal mode you can miss a target becuase the iron gives off a stronger signal than say a quarter. With a slow recovery speed the iron signal will come in first and if the good target is to close you could already be past the good target before your machine recovers. I run my detector in all metal and I go slow and low and I listen to the tones of a target. I run a Minelab E-trac in all metal mode. I dont discriminate out much. I get a lot of tones when I am detecting I know what iron, foil, tin, zinc, silver, and gold sounds like on my machine I let my ears do the disc. I have a multi tone option on my machine and it gives each target a specific sound according to it conductivity. My machine cost $1400.00 and I still have to deal with iron, its just made a little easyer with all my extra options. With your machine I would run the smallest coil avalible that would help give you a little target separation. Hope I didnt bore you. Its better to just go detect and dig everything.
Thanks
Todd

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Thats the best way to learn what your detector is doing. This is called air testing and it gives you a prety good idea of whats going on, but its not exaxctly how it will be when the targets are under ground. In the ground iron has what is called a halo effect and it can cause a small peice of iron to give off a signal many times its size. Now you can also try and put the iron above or below your coin and see what happens. You should be able to get more target separation with the iron above or below. This is where the more expensive machines start to shine. I once dug a silver dime at about 7 inches and in that hole I removed 5 square nails. The dime didnt come in with a perfect signal with all that iron around it but I could tell that there was something other than iron in the hole. Old iron that has been in the ground for a while will sound scratchy and rough like static. Metal detecting is fun but it take a lot of practice.

Todd

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