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P.I. coil for Sand Shark

A

Anonymous

Guest
Hi there. I have a Tesoro Sand Shark. I would like a nice little waterproof coil for this machine that I could use for sniping. If that is impossible, I'd like a sniper coil (say, about 4 inches around, or a little elliptical coil like Coiltek makes for the Minelabs).
I've found nuggets with this machine, but I'd like something a little more sensitive. The seven inch is the smalllest coil they make, and it's still too big for what I want.
Tesoro's coils for these machines are spiral printed. Is it impossible to make a small sniping coil for this machine? I've contacted Tesoro, but no luck--they just referred me to their 7inch, and I've already expressed my objection to its size.
Can anyone help? Can one be built? I've tried a lot of other places for help and I'm still coming up empty,
Lanny in AB
 
Hi Lanny
Check this out....
http://www3.telus.net/chemelec/Projects/Metal-1.htm
Garry did some experiments with small PI coils. Maybe he can help you.
Regards
Chris
 
The coil size your looking for, will most likely have to be made by you.
You may be unpleasantly surprised to find out that going to a small coil, wouldn
 
Thanks for your comments Mr. Bill. I didn't realize that the smaller size would not be more sensitive to small gold as Coiltek has made a very small, very sensitive coil for the Minelabs, which are PI's, and I believe it's called the Joey.
I'll be very disappointed if I can't get a small sensitive coil as I need to get into much smaller spaces while detecting, and the seven or eight inch coils are much too large, and they don't see smaller (under a gram) gold nuggets, and in crevices, there are lots of pieces under a gram that need rescuing by me, so that I can give them a new home.:)
Thanks again,
Lanny in AB
 
Thanks for the tip Chris. I'm looking for all the help with this that I can get.
Tesoro has responded once, but not to my follow-up response asking them for specifics. So, I'll follow any good leads I'm directed to.
Thanks,
Lanny in AB
 
I believe you will find the "Joey" coils were made for the Sovereign, Explorer Minelabs, and there not PI detectors.
To compound the problem, the sensitivity of the unit your using is not in the range you need. The unit had it
 
Chris,
Thanks again. I've looked at the page, but it has no links to his email, or how to contact him. Do you have another URL for a homepage, etc.? I've been doing searches, but no luck so far.
The info sounds good and might be just what I'm looking for.
Lanny in AB
 
http://www.kamakazi.com/docsplace/coiltek/coils1.html
Mr. Bill,
Thanks for your help again. I'm confused, as the above URL is from the North American Distributor for Coil Tek and the page states that the Joey is for the SD and the GP--pulse machines I believe.
What's up with that? Furthermore, they are touted as being highly sensitive to tiny gold.
Thanks,
Lanny in AB
 
I only thought they had them for the VLF units. Live, and learn.
Mr. Bill
 
Hi Lanny,
I believe you are correct, the Joey is made for the SD series.
Now, I have to agree with Mr. Bill, that a smaller coil will not necessarily increase the sensitivity to real small gold. It will, allow a person to get the coil closer to the ground, but the key to increasing the sensitivity to small gold lies in reducing the delay time for the sampling.
I have built several different sized coils and have even used a probe that is part of Eric's Goldscan which is about as small of a coil as one can get. What I have found is even with a probe, very small gold may not be detected, simply because of the longer delay.
I presently have different sized coils for my PI which I call a pseudo GQ and I really do not see much of a difference in the signal from small gold. I can, however, get closer to the ground or get into tighter places with a smaller coil. This is why I prefer to use a smaller coil in very rocky areas.
I am not sure how the Sand Shark generates the pulse and the delay, but I would try to concentrate on reducing the delay if very small gold is what you are trying to detect. My guess is the delay of your detector is over 20 usec, which would make most gold less than a gram very difficult to detect. I suspect this delay was set to minimize signals from small pieces of aluminum foil, while still providing a decent signal from a coin or a gold ring. Again, the rest of the circuitry will also have an affect as to just how loud the marginal signals may be, but the delay is the major factor.
I suspect you will have to build your own coil if you are wanting a smaller one. This is not an impossible task.
Reg
 
Thanks Mr. Bill,
I hope I can get someone to design one for my machine now, but I doubt Coil Tek would be interested in such a small order.
I appreciate your sincere comments,
Lanny in AB
 
Reg,
I once measured the pulse delay on the SS, I think you're right, it was on the order of 20-25us. Since it's set by the PIC chip, it cannot be changed.
I suggested on another forum that Lanny could build a coil, and gave him the inductance to shoot for. Unfortunately, Tesoro used a proprietary cable connector on the SS, and will not sell them to experimenters. <IMG SRC="/forums/images/frown.gif" BORDER=0 ALT=":(">
- Carl
 
Hi Reg,
Where would I go to find information on how to build a coil for my Sand Shark. I'm getting a little frustrated that Tesoro does not seem to be too intent on getting back to me with pertinent information about this topic, but, that's why I'm here. I understand this is the place to ask the questions, and this is the place to get some sound advice.
You're right about the need for a smaller, much smaller than the seven inch Tesoro makes as the smallest, to get into tight spots for nugget hunting.
Thanks for your clarification,
Lanny in AB
 
Thanks Carl,
I appreciated your input as well, and I've contacted a man that builds coils for PI's, and I've sent him the specs, and I'm waiting to hear back, but what's the deal with the "proprietary cable connector" that Tesoro won't sell? Does that mean I'm out of luck, or can something be adapted?
Thanks,
Lanny in AB
 
Chris,
Thanks again, I am currently in correspondence with the coil man! He's even developing a pinpointing coil that's about a half-inch diameter!
Thanks for the hot tip--I appreciate your time,
Lanny in AB
 
Hi Carl,
I wasn't sure if the Shark was PIC driven or not. One might try to cheat by just changing the crystal. This will change the delay using a back door approach. Hopefully, the PIC will work at a higher freq. Anyway's it would be a simple means if it would work, rather than having to change the pic. That would be a real pain, without a schematic.
I also didn't know about the special connector. One could change that I guess, but probably shouldn't do it if they are ever going to sell the detector.
Reg
 
Options are:
- Convince Tesoro to sell you a cable assembly. I wanted to adopt their cable connector for my own PI stuff, but they would not allow the manufacturer to sell them to me.
- Buy a Tesoro PI coil and snip off the cable. If you snip it long, you can use it whole. If you snip it short, you can make an adapter cable that converts to a different connector.
- Convert the bulkhead connector to a different style. With this, you run the risk of creating a leak, plus you would have to covert the std Tesoro coils over.
--Carl
 
Thanks for the solid options Carl. I really appreciate them.
What's up with Tesoro's attitude about selling their parts?
I've been very impressed with their machine, but I'm getting quite jaded with them, and their attitude, as any eager source of help with this matter.
Thanks,
Lanny in AB
 
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