Critterhunter
New member
I've toyed with the idea of building my own coils for my Sovereign GT in the past. Did a ton of reading and research on it. Then the SEFs came along and I figured I'd have to make several coils to make up for the cost of just buying a 12x10, because a coil of that general shape was what I was looking to build to improve both depth and left/right separation at the same time. This coil works so great that I don't even dare trying to better it with something similar in size.
But I'm still interested in the idea for a *extreme situation* sniper coil. Have a background in electronics so I can do the project, with enough reading to fill in a few blanks that I have.
I heard somebody mention it in another forum a while back and I think it would be a great idea- How about a 2" wide by 4" long sniper coil in the general style of an SEF in some respects? With a 2" or so wide width, the DD line could potentially be as sharp as a razor. I'm still shocked at how sharp the DD line is on the 12x10 due to it's shape which seems to compress the DD line width. And then, being about 4" (or say a tad less maybe even) in length, it's length wise separation would be outstanding as well.
A coil like this would be potentially awesome for working along fences or up against poles or other large metal objects, and of course would be stellar for working super heavy trash, such as sites that seem to be one big giant iron signal.
On the other hand, I don't know what limitations there might be in a DD's physical size in terms of length and width? I would suspect, that if Sun Ray can make a probe coil that ties into a BBS unit as tiny as that thing is, then you could get pretty small with a DD, although I doubt the Sun Ray's coil windings is anything related to a DD configuration. I would prefer a DD design due to it's awesome coverage and left/right separation abilites, not to mention they seem to be far less picky about alignment of the two coils compared to a concentric, and also the ability to suck up less ground mineralization, where a DD really seems to shine and punch deeper in my mineralized soils.
If anybody has any info on the specifics of BBS coil making, I still need to fill in a few blanks on that. I already have a schematic for the pre-amp in the coil, and being it's an off the shelf IC I can get that no problem, and easily pick up the few resistors or capacitors also involved.
Mainly I'm still fuzzy on the diameter of the wire and wire length to get the variables right for mating to the Sovereign, and how to go about fine tuning that. From the BBS coils I've read with a multimeter, despite shape or size, they all have the same readings on things like wire resistance, so I know you have to change length/diameter/turns to get certain variables within a window the detector wants to see. I've done a few custome winds on brushless motors for RC planes to get their amp draw, torque, or prop speed where I wanted it, which in a sense is very similar in the things involved- wire gauge, number of turns, etc. Just have to get the last few bits of things pinned down before building a coil or two.
Also, the shielding and such. One thing I hate is to shop via mail order. I'd much rather use parts at hand from local stores if I can swing it, even if the price is a bit higher on materials. Any useful items to shield the coil? I think I remember hearing that certain large capacitors have the proper shielding material in them that you can salvage for that.
As far as a coil casing goes, being such a small coil I don't think I'd opt for a commercial made product, unless of course the thing just looks killer. Instead, I'd probably just encase the windings in a solid pool of epoxy, poured into a custom mold of say 4x2 in size (4" long, 2" wide), and then make it look nice with a healthy dose of spray on bed liner like I like to use on the bottom of my coils to ditch the coil cover for less weight and no hassle of cleaning under them.
So if anybody has any bits or pieces to add material or technical wise on building a BBS coil, please give me any tid bits you may have at hand in advice...
But I'm still interested in the idea for a *extreme situation* sniper coil. Have a background in electronics so I can do the project, with enough reading to fill in a few blanks that I have.
I heard somebody mention it in another forum a while back and I think it would be a great idea- How about a 2" wide by 4" long sniper coil in the general style of an SEF in some respects? With a 2" or so wide width, the DD line could potentially be as sharp as a razor. I'm still shocked at how sharp the DD line is on the 12x10 due to it's shape which seems to compress the DD line width. And then, being about 4" (or say a tad less maybe even) in length, it's length wise separation would be outstanding as well.
A coil like this would be potentially awesome for working along fences or up against poles or other large metal objects, and of course would be stellar for working super heavy trash, such as sites that seem to be one big giant iron signal.
On the other hand, I don't know what limitations there might be in a DD's physical size in terms of length and width? I would suspect, that if Sun Ray can make a probe coil that ties into a BBS unit as tiny as that thing is, then you could get pretty small with a DD, although I doubt the Sun Ray's coil windings is anything related to a DD configuration. I would prefer a DD design due to it's awesome coverage and left/right separation abilites, not to mention they seem to be far less picky about alignment of the two coils compared to a concentric, and also the ability to suck up less ground mineralization, where a DD really seems to shine and punch deeper in my mineralized soils.
If anybody has any info on the specifics of BBS coil making, I still need to fill in a few blanks on that. I already have a schematic for the pre-amp in the coil, and being it's an off the shelf IC I can get that no problem, and easily pick up the few resistors or capacitors also involved.
Mainly I'm still fuzzy on the diameter of the wire and wire length to get the variables right for mating to the Sovereign, and how to go about fine tuning that. From the BBS coils I've read with a multimeter, despite shape or size, they all have the same readings on things like wire resistance, so I know you have to change length/diameter/turns to get certain variables within a window the detector wants to see. I've done a few custome winds on brushless motors for RC planes to get their amp draw, torque, or prop speed where I wanted it, which in a sense is very similar in the things involved- wire gauge, number of turns, etc. Just have to get the last few bits of things pinned down before building a coil or two.
Also, the shielding and such. One thing I hate is to shop via mail order. I'd much rather use parts at hand from local stores if I can swing it, even if the price is a bit higher on materials. Any useful items to shield the coil? I think I remember hearing that certain large capacitors have the proper shielding material in them that you can salvage for that.
As far as a coil casing goes, being such a small coil I don't think I'd opt for a commercial made product, unless of course the thing just looks killer. Instead, I'd probably just encase the windings in a solid pool of epoxy, poured into a custom mold of say 4x2 in size (4" long, 2" wide), and then make it look nice with a healthy dose of spray on bed liner like I like to use on the bottom of my coils to ditch the coil cover for less weight and no hassle of cleaning under them.
So if anybody has any bits or pieces to add material or technical wise on building a BBS coil, please give me any tid bits you may have at hand in advice...
....Obviously again, reduction by half this time from an 8" length to a 4" length, and a half reduction in width would then be from 6" to 3".
