Over the years I have had a some very good prospectors doing a fair bit of testing and providing excellent feedback on how to make things better, Big thanks to Bobby White up in Charters Towers, Peter from Melbourne and Matt from Ballarat. Just yesterday Matt came to me with suggestions on gain control and noise, after some discussion i had a brain wave that just had to be tried, I opened up Matt's detector and did a few circuit changes and after initial bench testing we went to the local gold area at Sparrow ground to do some testing. I have never seen Matt with such a big smile on his face, testing the GPX4500 on a 0.2 we could detect it at 8" with "no noise" the most interesting thing was at nearly full gain we were not getting much interference and the ground noise was minimal even using normal timings. It is a fine line designing an input stage that will handle the dynamic range of ground responses and still get maximum performance. This time I think we nailed it, some more testing will be carried out across the red hot ground of the golden triangle in the next few days. PS coils used were NF 17" elliptical and 17" Elite flat wound. The new mods tamed that Elite coil perfectly.
