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gpx 4500 with a 20" Nugget Finder coil

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Post  cat793 on Tue Jun 25, 2013 1:35 am

Hi all,

Would like to give this combination a go in WA to help cover more ground.

Anyone have any advice on settings?  General comments?

cat793
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Post  mulgadansa on Tue Jun 25, 2013 4:51 pm

Gday Cat
I too am a 4500 wielder. I do all my prospecting in the Murchison/East Murchison Districts of WA.
The bigger coils are great for patch finding and it's surprising how good they are on the sub-grammers as well.
Only drawback is the noise. They are just big EMI antennae but when the days are quiet they are very useful. I think everyone agrees that coils of this size are more efficient on the bigger, deeper pieces. The emi can get sorted out most times with a quick auto tune. Much worse in summer. There's only been a few times where I've had to change the coil size for something smaller that copes with the emi. If I'm running say a 14x9 mono and the machine is super quiet, I'll generally change up to a bigger coil.
cheers
Brett
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Post  cat793 on Tue Jun 25, 2013 5:08 pm

Brett,

Thanks for replying to my post.  Your idea about checking out the emi with the 14x9 (my usual coil too) and then moving up to the 20 inch if conditions are good sounds like the way to go. 

I have found it very frustrating detecting an area that I have not found gold and therefore do not even know if gold exists there at all.  Am I totally wasting my time or not?  With the bigger coil I feel that I could make this approach more efficient and satisfying subject to noise levels of course.  If I manage to find something then thrashing the patch to the nth degree then makes sense. 

One exasperating problem I had when I went out last (to Blackman's Find and Lucky Spot - didn't find anything) was the coil (14x9 CT mono) being very inconsistent.  I would manage to tune and ground balance it perfectly then stop for a rest after a while.  Turn the detector back on and tune and GB again and hopeless.  The coil would be quiet when sweeping but the combination of sweeping AND walking forward resulted in a long wailing tone up and down each swing.  No change to the procedure or settings vs when all worked fine previously.  I'm baffled by this.

cat793
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Post  mulgadansa on Tue Jun 25, 2013 5:35 pm

Cat, what time of year were you having the problem out at Blackman's with the noise on the smaller coil?
I use a NuggetFinder and it's a cracker coil. It too has it's moments on the first couple of trips in autumn but when winter's settled in it's magic. Even the smaller coils need auto tuning regularly early on in the season. I can't understand guys who say they use channel such and such all the time. I simply can't see it working, the machine would have to be unstable most of the time. Why manual tune when we have a very nice piece of automated equipment that runs through all those 270 (I think) channels for us and picks the quietest one?
cheers
Brett
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Post  cat793 on Tue Jun 25, 2013 6:14 pm

This was the weekend just gone.  I hold the same view as regards the tuning.  I always use autotune.  As I understand it the manual tune function is so you can fine tune slightly either side of the auto tuned channel.  I agree that always choosing the same channel seems nonsensical.  I am far from the most patient or thorough person when it comes to technical things however I do read the instruction manuals (eventually) and more or less understand them.  I think that a lot of even experienced detectorists are in love with old wives tales and all sorts of illogical make believe sometimes.

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Post  mulgadansa on Tue Jun 25, 2013 6:22 pm

Can't help you with the noise problem by the sound of it Smile. Maybe it was just a localised issue in that area. I did have one trip where the detector had me stumped but I later found out they were running magnetometer surveys in the area and that was what was killing me. Been back to the same area since and didn't have any problem.
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