Nugget Finder GPX 6000 Coils Delays

[Chet]

GPX 6000 test coils

I know of some areas that have produced some large nuggets. So in pursuit of large gold I have experimented with winding some test coils and did some air testing. Results are with my poor hearing and varying EMI conditions. But the measurements work for my comparison testing. On bad EMI days the larger coils are very noisy. A 20 inch 12 AWG Litz coil might be the next one to test. Meanwhile I am experimenting with some large GPZ 7000 coils.
Have a good day,
Chet

                   Coil Description                                                                                                     1oz gold coin Air test inches     
30" x 30" = 34"RND 1.86mm flat spiral Litz wire                                                                        27    
24" x 24"= 27"RND 1.86mm flat spiral Litz wire                                                                          27    
23" RND  2.3 mm 14T 3 vertical rows Litz wire                                                                          26    
17.5" RND 2mm Litz, spiral flat wound ID 14"                                                                              22    
17" RND Vertical Wound 2mm Litz wire                                                                                       21    
17" x 13" Minelab GPX 6000 coil flat spiral layers close wound 12 AWG Litz wire                   18    
11" Minelab GPX 6000  flat spiral layers close wound 12 AWG Litz wire                                   17    
14" Minelab GPX 6000 DD Coil                                                                                                    14    
6" GPX 6000 DIY flat spiral close wound 56 turns 2 layers 1.86mm Litz wire                          11    
 

[geof_junk]

Good table, most of my 1 oz nuggets are about the size of an Aus/Eng. silver 1 shilling or an USA quarter and shows there is not much gain in going over 18" round coil for that size.

[Aureous]

33 minutes ago, Chet said:

I know of some areas that have produced some large nuggets. So in pursuit of large gold I have experimented with winding some test coils and did some air testing

So you plucked the 'handshake' chip out the stock coils and made up an adapter for these tests? Fascinating results... The 6000 is not regarded as a deep-seeking detector, with both the 5000 and 7000 obtaining better results in all tests that Ive seen. But, these tests seem pretty good. All obviously mono's with but with proper shielding????

[phrunt]

Just look how close your pick can go to the 6000 when you have to work hard to keep it away from the 7000 ?

[Chet]

20 minutes ago, Aureous said:

So you plucked the 'handshake' chip out the stock coils and made up an adapter for these tests? Fascinating results... The 6000 is not regarded as a deep-seeking detector, with both the 5000 and 7000 obtaining better results in all tests that Ive seen. But, these tests seem pretty good. All obviously mono's with but with proper shielding????

I purchased a used GPX 6000 Mono coil and removed the cord and chip module together to accomplish the tests. I use a two conductor male and female connector to attach the test coils. I have tested some of these coils on my GPX 5000 which is unmodified. The GPX 6000 results are a few inches better than the GPX 5000. I shielded two of the coils with graphite conductive paint (100-150 ohms per inch). The before and after measurements where the same. The GPZ 7000 coils are more difficult to make and balance but is a better choice so that is that is the way I am preceding.

[Aureous]

45 minutes ago, Chet said:

I purchased a used GPX 6000 Mono coil and removed the cord and chip module together to accomplish the tests. I use a two conductor male and female connector to attach the test coils. I have tested some of these coils on my GPX 5000 which is unmodified. The GPX 6000 results are a few inches better than the GPX 5000. I shielded two of the coils with graphite conductive paint (100-150 ohms per inch). The before and after measurements where the same. The GPZ 7000 coils are more difficult to make and balance but is a better choice so that is that is the way I am preceding.

Cool, thats the smart way to do it, keep the coax attached to the chip and remove the whole lot. Shielding is spot on. Are these results all air tests??? Were you able to ground balance any of the larger coils or were they all board-builds only....without shells???

[Chet]

9 hours ago, Aureous said:

Cool, thats the smart way to do it, keep the coax attached to the chip and remove the whole lot. Shielding is spot on. Are these results all air tests??? Were you able to ground balance any of the larger coils or were they all board-builds only....without shells???

 

Two GPX 6000 coils; a 6" RND and a 26" x 22" were completed and tested in the field. They both ground balanced and worked fine. The 6" picks up smaller bits than the stock 11". The 26" x 22" was wound with 12 AWG stranded copper coated aluminum wire to reduce cost and weight. That was a big mistake that cost some inches off of depth. Litz wire is expensive so when possible it is reused to experiment with on the next brainstorm.? The attached photo is the 6" coil with the coax and module. The chip and ferrite housing is inside a blob of epoxy which now is covered with heat shrink tubing. The coil shield is connected by a separate spade connector
 

[Aureous]

4 hours ago, Chet said:

The chip and ferrite housing is inside a blob of epoxy which now is covered with heat shrink tubing. The coil shield is connected by a separate spade connector
 

Ha, you're full of great ideas Chet! Re-use the cable and chip for multiple coils....brilliant! Giving me ideas now... ?

[jasong]

Good stuff Chet. This kind of DIY experimenting is part of almost every enthusiast community from cars to computers, it really makes it fun and interesting to follow or participate in modding equipment for many of us. Goes to show Minelab isn't going to stop it with silly chips, and they should embrace it instead. Everyone wins that way! Good on you for keeping the experimenting, modding, and innovating spirit alive in the gold machine world. ?