For Critterhunter

[badarse]

Awhile back you were asking about building a small sniper coil. I had some spare wire around from an old project so I made this 5 x 9 double O. Video shows quarter nickel and dime. Very sensitive to small gold targets. I was suprised with the depth.

http://youtu.be/GnPyv1ID5BQ

 

[Critterhunter]

Bob, thanks for that. VERY impressive depth for sure in such a coil of that size. Thanks again for sharing some of the specs on the Sovereign coils in building one that they exect to see parameter wise (in the Technology forum under a thread I posted asking about this info). I could garner the TX winding readings I needed via the pin outs on the coil's plug, but with the pre-amp isolating the RX winding there would have been no way to derive such info without ripping a coil apart to bypass the pre-amp and get at the RX winding. Searched the web and managed most of the info I needed but that RX thing eluded me, as well as some aprox wire gauges to start with for both it and the TX to try some test windings on as a starting point.

I'm planning on sooner or later here trying to build an extreme 4x3 or even smaller extreme sniper coil, using an SEF winding layout as my template. Don't really care about depth abilities, just want smallest coil size possible for super heavy iron or other trash, as well as for perhaps getting right up along fences and other metal objects. Might not see much need once I play with the 7.25" Tornado more, but just the same smallest coil in terms of length wise aspects is for sure going to unmask some stuff other larger coils can't without hitting a ring of trash from just the right angle with the DD line to miss all that.

When I get around to the project I plan to film a how-to on it's construction. The biggest tricky part for me is using a scope to null out both windings. I have some aspects of electronics in my personal interests as a hobby over the years, and currently work in an electronics related field, but there are huge gaps when it comes to coil construction particulars. Never messed with a scope on stuff. I've done custom winds for brushless RC plane motors, which in some respects is similar to coil winding, but still I'm doing a ton of reading to try to fill in all the blanks.

Thank you again sir for posting that. You should be proud of that coil and the others you've built I've seen you post about in the past on various forums for the BBS units.

PS- Why would I want to build such a small coil? Besides the super sniper aspects covered above, smallest DD coil I can find thus far for other machines is a 4" round DD. Just for kicks I'd like to have a coil that is smaller than any commercial product of a DD for the heck of having it. If I can swing even smaller than a 4x3 I will try to, but I'm not even sure if the physical limitations of a DD field makes a 4x3 all but impossible to make. Only way to know is to try I guess, and then go from there.

I've already located schematics for the older and newer versions of the pre-amp. Plan to use the newer version. Relatively simple circuit to build. I see there is also a pre-amp layout floating around out there that somebody did using a different IC and a different schematic they came up with. Have you dabbled with that one yet and did you find any enhanced properties to the initial gain done with it on the RX signal?

What I think might be interesting to do is to use that circuit and then stick an external gain control POT on the shaft say about halfway up to the machine, and then you could perhaps increase the gain for some low EMI/minerals situations even before it reaches the 2nd gain control of the sensitivity dial inside the control box. Wonder if that would have any benefits, so long as the noise isn't also amplified too much. Maybe stick a small pot right on top of the coil instead and do it right there tweak wise? Interested to hearing your thoughts on this sir.

Thanks again for filling in some of the gaps and also showing us your handy work on some custom coils for the BBS units...

By the way, have you dabbled in any concentric builds for your BBS unit? While I much prefer a DD for depth in my mineralized soils and also left/right separation, might be fun to build say an 8 or 12" concentric just to see what traits it might have in certain situations. PPing might also be rather sharp for a Minelab.

 

[Ron from Michigan]

LOL that's one ugly coil.HH Ron

 

[badarse]

I have tried a concentric but had poor results so I abandoned the idea. Guess that's why you don't see any after-market manufacturers selling any?

Bob

 

[badarse]

Yeah I know looks like mickey mouse ears but who cares if it works good!

Bob

 

[mudpuppy]

That's awesome! The "Mickey Mighty Mouse" or the "Infinity Branding Iron" great work! evidently some knowledge and understanding in both electronics and epoxy work here!
Mud

 

[Ron from Michigan]

Very good idea and work.Thanks Ron

 

[JimmyCT]

Bob,
fantastic work and impressive depth!

 

[Critterhunter]

Yeah I know looks like mickey mouse ears but who cares if it works good!
Bob

Hey Bob, I don't care if that coil had a Mickey Mouse face painted on it, fact is those air depths are pretty impressive for a coil of that size, and I suspect (?) you weren't even running at full sensitivity due to doing that test in your house with EMI issues? And I bet it'll in some soils or sands get even more depth, as is always said about these Minelabs not air testing as deep as they'll go in some soils/sands due to the unique way they need a ground load.

You should be proud of your handy work there. I bet it gives you great satisfaction. Nothing like building something yourself, saving money, and also getting just what you want in modding or building something. One of the reasons why these Excals and Sovereigns are so popular- Easy custom modding like, as I read somebody once say, making a custom hot rod. They lend themselves to that.

Speaking of Mickey Mouse, a newbie to detecting was brought under the wing of our local circle of hunters to show him the ropes. Great guy, and I tried to encourage him to use that entry level machine of a particular brand and not be so discouraged with it's depth compared to our Minelabs, telling him there are plenty of shallower good finds out there that many of us pass right over thinking we know better as to what is worthy to dig most days.

Anyway, another friend and I were taking a break, and just to crack a joke, as we watched the new guy hunt off in the distance, I asked my other friend if he thought a Mickey Mouse hat came with that machine the new guy was using. He laughed and said "Why don't you say that?" I said no way, as I didn't mean any harm by it but didn't know the new guy's sense of humor yet as to how he might take it.

Well, later, the new guy takes a break and walks over to sit with us, and my friend uses that line on him. My friend looked at me for support, and I hung him out to dry and said "That's cold! I can't believe you'd say something like that." He laughed, the new guy laughed, all of us for different reasons. Later that day I owned up and told the new guy the dumb line was mine but I didn't know his sense of humor yet, but before that my other friend got a big kick out of it, when I kept telling him "How do you like how I hung you out to dry?" before finally fessing up to the new guy later.

Since then the new guy got an SE Pro, and now, as a joke, I keep telling him I'm going to pick up a Mickey Mouse hat for my other friend who used that line to wear when he's out hunting, as that SE Pro will hang with the best of whats out there these days. It's all in good fun, and that's the best part of this hobby...Sharing moments with good friends. That's the true treasure in it for me these days...

 

[Nauti]

Well done on an excellent job.....great air test depth for a small coil and has a purposeful look about it.....i'd have one.

 

[GunnarMN]

This may be the coil that brings me back to the GT that is cool

 

[badarse]

n/t