Shhhhh!
June 04, 1998 at 19:20:06
In Reply to: A question for AL (AZ), Viper, and others.....
posted by Ralph on June 04, 1998 at 16:31:31
Ralph,
Coil size, windings, target size and type, among other factors play a major role in a PI's sensitivity. Depth is relative to coil size. An 8" PI is equivilent to a 14" VLF, MOL. In extreme soil conditions, i.e., high concentration of black sand with alkali, or salt domes, there is no contest, the PI will punch through it better. Any good machine can find iron, a good PI will find it deeper in extreme conditions, as well as non-ferrous metals. Why do you think professional salvage divers use high end PI's? If there was a better VLF, it would have been waterproofed long ago. Again, one machine can't do it all, and some do different things better than others (I still havn't found where the Scorpion shines) under specific conditions. If you are working close to bedrock, the gold is small, and mineralization is not a problem, A white's V/SAT, LST, Diablo's, Lobo, Gold BUG's, etc., is all you may need. You have to match the conditions to the machine, and each machine seems to have its own niche. I shoot rats with a .22, not a 460 Weatherby magnum, either will kill a rat.
On our claim, we are below the trash (bits of iron, etc.), but the closer we get to bedrock, the more concentrated the mineralization becomes. The country rock is hot to begin with, similar to some exposed bedrock in Last Chance Canyon (El Paso Mts., CA). Some VLF's handle extreme alkali beter than others, but there comes a point when it's nearly impossible to pick out a good signal from all the chatter.
Consider the Minelab XT's, in moderate conditions, the threshold is so unstable, you have to guess which "whisper" is true or false, add a few small bits of iron to the matrix and it gets worse, and the recovery time is slow. When you lose confidence in a machine, it's time to change. It's hard for me to warm up to automatic ground tracking, but from my limited experience with the LST, it's light years ahead of the XT's. Screamer's near the surface are easy to find, it's the faint deep whisper that often turns into a nice specimin.
The biggest disadvantage of a PI, is pinpointing a small target. It takes longer to isolate a small piece. That's a small price to pay, if you can locate it in extreme soil conditions. Al (AZ), and Steve, in Oz, know what I'm talking about. Some prospectors have never experienced extreme conditions, and most that have, just moved on.
The PI is a deadly effective weapon in really extreme soil conditions. Is it a tiny nugget (1/6 grain) detector? No, but neither is the SD, you still need to scan for smaller pieces with a machine designed for that purpose.
The SD's and PI's are both hot on small bits of iron. The biggest advantage of the PI, is under extreme conditions. The PI doesn't eleminate VLF's it augments them, one machine can't do it all! I don't want to split hairs, use what works for you, but keep an open mind. I checked my SD against my partners Pulse 8X and it blew the SD away for depth, and it should have, the 8X had the advantage in coil size. I'm going to put the small coil on the 8X and the 11" on the SD and try it again, it should be a closer match up. I may try a nickel test as well, all this controversy has renewed my interest in the ongoing battle of the two machines. I was sickened when the 8X could pick out the nugget at 19 inches. I'm a consumer, it's my funds that purchase this equipment, and I am sick of hype! Tell the truth, I can handle it. Manufacturers need be more truthful in their ads, and field tests they pay for. Of all the brands I pay attention to, Tesoro seems to present a more honest ad campagn, and I'm not a Tesoro fan.
HH
Viper
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