GMT false signal on water

[k man]

Can anyone tell me why when I pass my coil over water it sends of a false signal.I've noticed my hand also dose it when checking my digging in my hand for nuggets just with hand fulls of dirt.I can solve this problem by using a plastic scoop but as for the rest I a puzzled.the first time I noticed it was when I had a ounce jar vial full of water and about half a gram of flower gold I had panned.when I ran the coil over it I got a sweet little signal that I was wrapped about but when I picked the vial up of the ground I noticed the vial with gold in it was still in my pocket and the one I was testing on had only water :8 after a few curse words of stupidity I changed them over but this has left me puzzled.any advice would be gr8.the coil is the stock 10/6

 

[Guest]

Not sure about the water but I know that the GMT will pick up salt in your skin. There is a statement in the manual about it. I had to use a scoop with it as my skin was always signalling.
Is the water fresh or salty? Also does the vial lid have a seal containing foil?

 

[k man]

It was fresh water and there is nothing on the vial to send out a signal.it has also sent of a signal when I tryed to pass it over a small creek near Ararat and when I went to submerge the coil to test the black sand function it screamed its head of is this normal? I wouldn't think so I have my settings set at the standard Australian settings

 

[Guest]

No not normal. Used mine in/near water a few times & never falsed at all. Might be best to give the blokes at Goldsearch Australia a call & see what they reckon?

 

[k man]

Thanks mbasko that's the info I wanted to here.I have a reasonably new coil from them the GMT I bought 2nd hand but it originally came from them as well.I will give them a call.would be interesting to see how common/ uncommon this is I know they are a pretty sensitive machine.

 

[backcreek]

I'll have to agree with Mbasko. I have used my GMT with the coil submerged underwater in creeks and never had a false signal.
Just make sure the lead is secured to the shaft so it cant move around in the water.

 

[k man]

Yep got the coil taped at top and bottom of shaft to keep from moving.hopefully I can get a chance to ring the boys in dunolly today to get a diagnosis

 

[Reg]

One of the things I ran into was some of the small vials had a gasket inside the top that had a thin piece of aluminum sufficient to cause a signal on a detector. So, you might try to detect the vial with the lid off and see what happens.

Reg

 

[k man]

Good idea reg I'm pretty sure it doesn't but not to say one is hiding there.so I rang the guys at dunolly and they say it could be caused by running high gains and possibly lifting the coil to high of the ground at once and going back down over water so I will experiment with settings again and post the outcome

 

[k man]

So I have done a field test/back yard test with lower settings on gain and v sat and ground balanced then came up to my little fellas wading pool for the big plunge.surprise surprise no false signals.I am pretty confident I did all this last time but this time all fine.I flicked a 5 cent piece in that was sitting on my pocket and hey presto it only signaled when I past over it and quite every where else in there.the only other thing different I did was re tape the coil at the top of the stem where it couples into the top stem.I did notice it was hard up against the top stem piece and could have been pulling/kinking the lead downwards when it was joined together.a little tip I picked up through conversation with the dunolly boys when they mentioned the words pulling on the cord can give of false indications.all in all my confidence is back in the GMT and starving for another gold fields trip thanks everyone for there posts and support. gr8 forum indeed