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I recently purchased a new 11" Commander Mono coil for my GP3000 and just put it on for the first time today to test it in my yard. I went through all the exact same tuning and set up steps, including flipping the coil switch to Mono, as I do with my NF and the stock DD but the threshold now will not smooth out at all. It does sound off when swung over a target, but the threshold constantly sounds just like the noise the machine makes when you press the Tune button and it searches for the quietest channel...real chattery and wobbly. Is that normal for this coil to sound like that? I put the stock DD back on and it smoothed right out. Put the Mono back on....wobbly and chattery again? :wacko:

Am I missing something or doing something wrong? Thank you.

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Rob and Flak......

Well, you can certainly tell that I am still wet behind the ears when it comes to this detecting stuff. There are power lines that run right over the top of my fence line. When I am standing in my yard they are about 80-100 feet away. With the stock DD coil, once I did the set up and hit the tune button, even with the lines that close, the threshold is really smooth and stable. So I just figured it was the same way with the isn't! LOL.

I did as you both suggested and took it out to the field across the street and it quieted right up. Awesome! Thanks so much.

Now for just one more stupid question.... I know while working in the discriminate mode the ferrous objects will cause the signal to "blank". What about while working in All Metal? I mean, I hear the difference when it comes to the Hi-Lo signal and the Lo-Hi signal, but what do they mean exactly? I assumed that a Low to High sound would be "ferrous" whereas the High to Low would be "non-ferrous"?

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The classic sound of a nugget is High to Low and reverse for the larger ones. Now every experienced detectorist will tell you that all nuggets small or large will not make the same text book sound. I'd like to tell you to dig every target in a patch of gold. I still dig several square nails each week in old gold patches to include nuggets...Dig them all and let your scoop sort them out! You'll sleep better at night, knowing you didn't leave a funny sounding fat nugget for the next detectorist.

Good luck,


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Hey Chris,

Had a good feeling it was probably EMI, which is the power lines running across your area. The Mono's seem to pick up more EMI then DD's. If you just want to play around at home with the Mono, place your detector in the "Cancel" mode and you will elliminate most of the EMI, if not all of it. You will loose 50% or more of your depth and sensitivity with a Mono, but you can still play with it. Use the "Cancel" mode with your DD and gain a good portion of the lost depth and sensitivity back. Play around with it and see what you can do.

Like Lundy mentioned, don't put any faith in target responses. Dig everything if possible to ellminate missing a nice nugget along the way. If I could only count the multi-ouncers that I would have left behind that didn't give the typical "Wee-Woo" or "Woo-Wee" signal. :blush:

P.S. Received your PM, I'm back home now. Sounds like you were able to get a good deal on the Pro-Pack.

Talk with you later,

Rob Allison

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I also have a GP 3000. Once in New Mexico I was detecting. I did the air tune thing, no overhead power lines, just a cell tower about 2 miles away. Detector was operating smooth for 1/2 hour. Then it bugged out, sounding like a european ambulance with the pocket rocket and speaker. After a couple of minutes I noticed a metal 4 foot pole sticking up from the ground. I was over a gas line. Wow! these detectors are powerful. I now prefer ground tuning.

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Gday Chris

Mate dont forget that even if there aint a power line too close you can still get bad EMI from the fence that runs under a powerline some miles away, cause the fence acts like a massive antenae and carries the EMI for miles mate..

Pete in WEST OZ

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I have learned a lot in this thread. Everyone's input is much appreciated. It is amazing just how powerful these things are. Such a huge difference between these and the VLF machines I have owned.

I was told in a phone conversation last night that EMI is pretty much non-existent with the 4500 and up machines. Why is that?

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