Interesting thread...
I owned the Sand Shark in the past, and my current PI machines are the Infinium, and the Minelab F3 mine detector. I am a person that is on a never ending search for the most sensitive waterproof PI for my beach hunting endeavors...
I mainly beach hunt for gold, but do so in Southern California on some very highly mineralized black sand. As an example of how hot the sand is, half of the beaches in my area the Sand Shark saw the whole ground as a target... no amount of tweaking the settings allowed me to swing over the ground without an overload signal... ground balance on a PI is useless Terry?.. The Infinium and F3 run flawless on these same beaches with completely stable thresholds and seemingly unaffected depth... after ground balancing of course.
Also as hinted at by others in this thread, the Sand Shark is not nearly as sensitive as the Infinium or F3. The depth difference is most noticeable on the smaller gold, <2 grams, but there is an obvious difference across the board, target size wise. Where my Infinium hits a 1 gram 10k gold ring at around 9", the Sand Shark hit it at about 4"... The Infinium hits a .5 gram 10k ring at around 6", I doubt the Sand Shark would even see the ring (found it after selling the Sand Shark..). After some testing the F3 seems to be slightly deeper (<1") than the Infinium across the board.
Unfortunately, Terry is a stubborn New Yorker, and no matter how many facts you throw at him, he is always right. It's just sad how many mediocre Sand Sharks are sold to new detectorists because of his bald-faced lies.
Also, apparently he has over 200 hours on every machine... he said the same about the Infinium and Dual Field in another thread when claiming the Sand Shark is better than both...
With all that said, IMO the Infinium and TDI are not overpriced, when considering how much better they perform than a $600 PI like the Sand Shark. If I was to get into gold nugget shooting, I would either buy a GPX5000, or use a Gold Bug 2 + Infinium/TDI.
Terry comparing the high operating frequency VLFs to the PIs just shows his ignorance... very different animals.
It is sad to see a thread with so much good information, from so many experienced and knowledgeable people, get thrown off topic by Terry's dribble.