Hi George,
First, let's take a closer look at this quote:
"But all of the above is speculative as we really don't know what the TDI is capable of. We may indeed laugh at our discussions here when the TDI is released and commented upon."
Well maybe some folks, but not me; nearly all conversation here has been about how the GS5 functions...and if the TDI doesn't fit, the GS5 looks almost ideal, period. One quick little GB adjustment and a second reading over the same target should provide a good indication of whether the target is high/low conductive...or iron...if I understand correctly. Also, no iron falsing is a dream. Thanks to your information, I now appreciate a good deal of this unit's potential.
Let's move on to another quote, since I want to comment on the final result:
Well this is not really correct as the larger pulltab is not in the coin/high conductive tone range. It still is a lower conductor. Instead of using different sized pulltabs let's use pulltabs and screwcaps. Same material but the screwcap is slightly larger. The GS5 will ignore the pull tab but pick up the screwcap on our 10:00 setting.
On a VLF the TID will read the following.(Well it would vary on which machine you would use)
silver dime 38
screw caps 28-30
The square tab with 2 holes = 26
The square tab with one hole = 24
The big pop top ring = 20
It may after all be size discrimination using the 10:00 position. Small dime size low conductor silver specimens may be ignored whereas quarter sized specimens detected. Playing around with actual silver specimens would be interesting and would reveal what the truth really is.
OK...you've made reference to "lower conductor" pulltab and screwcap "size discrimination" in reference two different configurations of aluminum. My point is that all of these traits...size, metal conductiveness, shape, structure...
ultimately result in a final conductivity rating by the detector. Yes, indirectly for example, size is considered by the detector insofar as it contributes to the conductivity, but the detector circuitry does not report the size, or shape or structure and so on, but rather it reports the final verdict in terms of conductivity. Including your items conductivity ratings above, indicates in the final analysis, that you agree, (I think).
Thus, for manufactured items of precision repeatability, it is very easy for circuit designers to establish where different known configurations will read on the meter, and thus where we can set discrimination with a reasonabe knowledge of what will be included and excluded. A screwcap for instance, because of different physical traits than a pulltab, despite identical metal composition, has a higher conductivity, and as you say for a 10:00 position..will be included with the high conductives.
If there were two (metal content, purity, structure and shape) identical silver pieces of different size, then yes, the larger size would have the higher conductivity rating on the meter (up to a practical point ultimately); but in the case of naturally occurring ores, all ores are random to varying degrees. There is no doubt, I'll readily concede, that size must have some undetermined effect, but you cannot directly predict randomness (as compared to manufactured precision) without precise scientific measurement and statistical analysis to high confidence limits for an extraordinary large number of samples (theoretically); and therefore we will find in practical application, that many small and large high conductive pieces will fit into the high conductive tone, but an appalling number of beautiful, small and large pristine native silver ores (due to some structural trait, intrusive mineralization, whatever) will have conductivities identical to or less than nickels, thus falling into the low conductive tone....and size has no apparent impact at all, or at least not nearly enough to rival the impact of other more decisive factors. Take a good look at the native silver in calcite picture posted above; it's conductivity on a White's Spectrum is exactly "8"...the middle of foil range, because the calcite is loaded with iron mineral. Yet I can show you innumerable small nuggets no larger than a quarter, that would read in the screwcap to copper penny range...why.....no mineral. Size is not the decisive factor at all.
Well, that's the best case I can make here; I'll concede the best logic must meet satisfactorily with reality, or otherwise bow to it. Otherwise, come prospecting with me, you'll have such a memorable and thoroughly enjoyable time, by the end of it you'll be willing to agree the sky isn't blue... if you can stay clear of the bears, that is.
One final thing George, I'm not at all clear on the ground balancing of mineralization. I understand about setting the GB for disc purposes, but how do you determine where to set it to ensure iron mineral is balanced out? What's the relationship, or main decisive factor...or is it just a case of having an adjustable range where any setting in that range will do in low mineral, but the range is more restricted in higher mineral? This is the key question that I do not understand. And BTW, how much $ dollars is the GS5?
Jim.
Any input on how it should work for detecting Meteorites?
