Topics

76

Technical / DC Offset in operational amplifiers in DC coupled front ends of P.I detectors

« on: January 04, 2014, 02:58:13 pm »

After testing the input stages on various detector I have found that many of the AD797 opamps with a spec sheet indication of 25mv DC offset is not the case when measured in some detectors.
Offset voltages in excess of 100mv are quite common.  Adding a potentiometer and trimming the Offset after 15 minutes run time to DC makes for a much more stable and quieter detector. As the first stages are DC coupled, reducing the Offset voltage makes for a much more behaved quieter detector. Frequency compensation can also be carried out to reduce Radio Frequency interference without degrading the low frequency slew rate or settling time of the opamp. 

77

Technical / Hot Weather Cold Weather Dry ground Wet Ground Daytime Nightime.

« on: December 30, 2013, 07:20:37 pm »

Hot weather = Less Nuggets detected.
Cold Weather = More Nuggets detected.
Wet Ground = Less Nuggets detected.
Dry Ground = More Nuggets detected.
Night Time  = More Nuggets detected
Day Time   = Less Nuggets detected.

Why?   Who knows the answers?

78

New Detector accessories / New add on for any Minelab with a massive improvement in performance.

« on: November 19, 2013, 05:26:55 pm »

I have been working on a complete new add electronic signal conditioning unit that will allow the detection of Gold at far greater depths and increased sensitivity to smaller Gold as well. Initial tests in the Lab are outstanding, now just have to go bush and do some more testing on real red hot ground. This new technology will open up the Goldfields like the early days of detecting.

79

General Discussion / Nugget Patches

« on: November 18, 2013, 07:03:42 pm »

Here is some nice Gold.

80

General Discussion / Nice big Gold Nugget from Victoria.

« on: March 09, 2013, 04:42:29 pm »

With Permission... Maryborough Gold.

81

General Discussion / Gold Gem and Treasure magazine

« on: February 10, 2013, 05:38:11 pm »

I will be writing monthly articles for Gold Gem and Treasure Magazine, so I will be writing about my 33 years as both a prospector and electronics designer.  There will be many articles that will greatly improve your detecting.. 

82

General Discussion / New Mods being worked on.

« on: September 26, 2012, 09:43:44 pm »

I have not posted much, been busy developing a new set of upgrades. It will be a couple of months before we know if they live up to expectations or not. The aim is to get big Gold deep and to get smaller Gold at greater depth in light mineralization. Believe me this is a real challenge and very difficult to do.

As long as you start off with a Minelab P.I detector you will be doing great, to this day nothing beats a Minelab for the big deep Gold.

83

General Discussion / The Ultimate detector project

« on: August 26, 2012, 01:27:24 pm »

Just an update, well i can only say a little as there are non disclosure agreements in place that are legally enforceable.  The development is still current.  Will it be the best P.I detector every released?  Yes it will be.  Initial results are very promising.

Please try to understand that all the design work we do is currently very commercially sensitive, we have had many attempts of hacking into our collective computers.It was so extreme that we had to move all our design work to non internet computers.