Hi to all.
Having recently purchased a GPX4500 complete with the standard 11DD and 15 mono I was feeling a little depressed with performance until doing a day training course with 'Golden Triangle Tours'.Not only was the course excellent, it was the testing of different coils with my own machine that made it more than worth while.
Without doubt the best coil tested on different size nuggets buried at different depths was the Nugget Finder 12 inch evolution mono. I was amazed at the difference, the 12 inch evo was the only coil tested capable of detecting all nuggets at all depths. Just an excellent all rounder. ( the trip home proved it when a couple of rocks that gave a subtle response from Rushworth were dollied to shed some good flakey gold)
I have since purchased said coil and continue to be impressed. Mind you, do not try and use in a residential area unless you are happy to adjust the detector response including Rx,,, it is very sensitive to EMI. Great out in the field, just be mindful of EMI sources such as phone towers, approaching storms, even two way radio devices and electric fences in the vicinity.
This coil performed better than 8x6 mono (NF) I was originally going to purchase for small gold.
If possible check out Greckie at Golden Triangle Tours before purchasing a new coil. The new evolution coils are class above the standard coils, and as pointed out in earlier posts it is water proof to 1m.
Cheers
Diablo