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Coil Management
- Thread starter matthias
- Start date
Critterhunter
New member
My theory is that the fastest and most straight way to get the cable away from the coil *might* improve performance slightly by allowing you to raise the sensitiviity a tad higher. After all, there is copper and aluminum in that coil cable. So I route the cable straight up the shaft, and I don't coil it until it's past the hand grip right around the write/forearm area. I also have the cable secured with velcro well from the coil on up, because the cable flopping around (especially down by the coil) can cause interference. I've seen some guys really have a sloppy cable that is flapping around in the wind down by the coil and wonder how much performance that is costing them. Are they having to lower sensitivity to compensate for it? A prime example is that video comparison of that new Bristool detector to the Sovereign on a beach. Look at how badly that guy "winded" the coil cable around his Sovereign.
I run mine straight up the shaft until it gets close to the hand grip. I don't like the 20 turns of unshielded cable wrapped around an aluminum shaft. That's an inductor any way you look at it. Maybe not much but since inductors resist a change in current flow, an amplified multi-frequency signal flowing through the cable would see the greatest resistance to change. I shortened the cable on the 10" tornado I now only have 6 turns around the shaft. There appeared to be an improvement in coil performance but that would have to be validated by more than just myself. However I believe it so much that I will be shortening my 12x10 SEF in the near future.
HH
Ran
HH
Ran
Critterhunter
New member
Don't shorten it if you ever plan to water hunt with that coil. I've thought about doing that but what stopped me was water hunting or resale value to somebody who water hunts or hip mounts the box. If they hip mount the box it wouldn't matter, because if they were using a DigiSearch meter there is of course plenty of extra cable coming off that thing too.
Interesting points about inductors. You know, I did read about somebody who coiled his cable in a small loop that he then hung from his detector around the grip area. Might have been the same lines of thinking you have and that's why he did that. It isn't wrapped around the aluminum shaft that way.
Interesting points about inductors. You know, I did read about somebody who coiled his cable in a small loop that he then hung from his detector around the grip area. Might have been the same lines of thinking you have and that's why he did that. It isn't wrapped around the aluminum shaft that way.
Pretty much the same as above - straight up the coil to near the handle. For the low power of a metal detector, I'm not sure how strong the inductance would become if you have the wraps spaced apart from each other; right next to each other, there has to be some inductance, further apart, I'm not sure it would make a big difference. But, to be on the safe side, I route my cable like the others have said. I have a bit of a half-loop so I can take my rig apart at the joint so I can put it into the car trunk when I'm not in the car. No need to leave it in plain sight for others to be tempted by... A similar half-loop at the bottom so I can move the coil angle.
I run mine a turn or 2 on the lower shaft, then wrap it tight around the the rest of the upper shaft starting right where the shaft lock is. The thing is to wrap it tight so it will not move.
On my older 8 inch coinsearch coil I cut off some of the cable so I didn't have to wrap it as much and myself felt it run quieter and seem to do better on depth as I seem to find more deeper coins than I did before as I felt too that a coiled cable or wire is inductive, but was told it shouldn't make that much difference, but I felt it did for me.
On my older 8 inch coinsearch coil I cut off some of the cable so I didn't have to wrap it as much and myself felt it run quieter and seem to do better on depth as I seem to find more deeper coins than I did before as I felt too that a coiled cable or wire is inductive, but was told it shouldn't make that much difference, but I felt it did for me.
deepdiger60
New member
That may be one of the reasons the SEF coils work so well the one i have for my DFX there is no reason to shorten the coil wire it runs straight up the shaft without any twist around just 3 wraps of black electrical tape from bottom to top of shafts it just makes it to the control box with maybe a inch to spare , compared to other coils that have over 30 inches of useless wire that has to be twisted around the metal shafts , every chance i get i will replace a shaft with a Carbon Fiber Shaft 1/2 the weight and non metallic . Jim
Critterhunter
New member
Some of the early SEF coils for the Sovereign had shorter cables but now they are pretty long like the one I got.
deepdiger60
New member
That is because most hip mount the GT without a search probe in between , me i have the Sunray S-1 so all i need is a short wire from the coil , the probe has a 50" wire to the control box hip mounted . JimCritterhunter said:
ok so i am putting my new(used) wot coil on my sov xs and there is a lot of loose coil so i look at the minelab manual and it says wrap between 25 and 28 turns, now i read this post and i am really confused, do i wrap up tocontrol box a few times and then the rest from there on ? does it make a difference if they are loose coils or tight coils but not to tight to cause a problem, any ideas ? larry
Critterhunter
New member
You can look on page 2 of the Sovereign accessories sticky to see a few pics of both my water and land rig to see that, and there is also a few pics there of how somebody else wraps his coil on his GT for other ideas.
The primary thing IMO is to get the cable as far away from the coil as fast as possible. For me that means I run it straight up to the shaft at an angle (roughly it meets the shaft like 4 to maybe 6" up the shaft, secure it there with velcro tightly so the cable in the air between the coil and where it meets the shaft several inches up won't be flopping around with coil movement.
In the water this is even more of an issue, because if they cable isn't tight between the coil and where it meets the shaft say 4 to 6" up or whatever on the shaft, IMO you are asking for a short in that cable right above the coil as the cable keeps moving back and fourth due to water resistance.
In fact, I'm even thinking in my water rig I might run the cable straight across the top of face of the coil tightly and directly to the shaft base on top of the coil, secure it there good, and then tightly straight up the shaft until I coil it behind the grip. In the water even if the cable is tight but still in the "air" going from the coil to the shaft like 3 to 6" up it or whatever, that part that is hanging out in the open like that I think is going to maybe move back and fourth with your swings through the water, and will eventually lead to a potential short right above the coil where it the cable enters due to stress that can't be relieved by normal coil cable length moving around. Such as is the case with a hip or chest mount.
Not much risk to a short in the cable going from the machine to your body. That 2 or 3 foot of cable has plenty of length to flex and bend and avoid putting stress on any one area of it. It's that last little bit right where it attaches to the machine where the stress is born out due to no cable wire past that spot to move and flex and take stress away. That's why it's important to loop the cable a few times loosely when hip or chest mounting right before it travels on to the control box.
But for land, I don't think from the coil to the shaft is going to be pushed around in the air, so I just tightly run it at an angle through the air right to the shaft to get it as far away from the coil as fast as possible, and then I go straight up the shaft with it without wrapping it, and I only then wrap it once it passes the hand grip, so it's coiled around the shaft in the wrist/forearm area of the shaft on my side of the grip.
Now, for my water rig, I'm still trying to figure out what to do with the contact point of the cable where it leaves the shaft and begins to travel to my chest mount. I'm worried with continued movement/stress put on the cable right where it meets the shaft there I might develop a short in that spot. For that reason, I think I need to also loop the cable in two small loops right there lightly, so they can give and take as conditions warrant and not put any stress on one small area. Same way I loop the cable twice at my chest mount on the Minelab bag, as it has a loop hole for this, and it needs to be done as small as you can but staying rather loose, because you want those two loops to flex and move and not put pressure on one tiny length of cable. That's my thinking anyway...
The primary thing IMO is to get the cable as far away from the coil as fast as possible. For me that means I run it straight up to the shaft at an angle (roughly it meets the shaft like 4 to maybe 6" up the shaft, secure it there with velcro tightly so the cable in the air between the coil and where it meets the shaft several inches up won't be flopping around with coil movement.
In the water this is even more of an issue, because if they cable isn't tight between the coil and where it meets the shaft say 4 to 6" up or whatever on the shaft, IMO you are asking for a short in that cable right above the coil as the cable keeps moving back and fourth due to water resistance.
In fact, I'm even thinking in my water rig I might run the cable straight across the top of face of the coil tightly and directly to the shaft base on top of the coil, secure it there good, and then tightly straight up the shaft until I coil it behind the grip. In the water even if the cable is tight but still in the "air" going from the coil to the shaft like 3 to 6" up it or whatever, that part that is hanging out in the open like that I think is going to maybe move back and fourth with your swings through the water, and will eventually lead to a potential short right above the coil where it the cable enters due to stress that can't be relieved by normal coil cable length moving around. Such as is the case with a hip or chest mount.
Not much risk to a short in the cable going from the machine to your body. That 2 or 3 foot of cable has plenty of length to flex and bend and avoid putting stress on any one area of it. It's that last little bit right where it attaches to the machine where the stress is born out due to no cable wire past that spot to move and flex and take stress away. That's why it's important to loop the cable a few times loosely when hip or chest mounting right before it travels on to the control box.
But for land, I don't think from the coil to the shaft is going to be pushed around in the air, so I just tightly run it at an angle through the air right to the shaft to get it as far away from the coil as fast as possible, and then I go straight up the shaft with it without wrapping it, and I only then wrap it once it passes the hand grip, so it's coiled around the shaft in the wrist/forearm area of the shaft on my side of the grip.
Now, for my water rig, I'm still trying to figure out what to do with the contact point of the cable where it leaves the shaft and begins to travel to my chest mount. I'm worried with continued movement/stress put on the cable right where it meets the shaft there I might develop a short in that spot. For that reason, I think I need to also loop the cable in two small loops right there lightly, so they can give and take as conditions warrant and not put any stress on one small area. Same way I loop the cable twice at my chest mount on the Minelab bag, as it has a loop hole for this, and it needs to be done as small as you can but staying rather loose, because you want those two loops to flex and move and not put pressure on one tiny length of cable. That's my thinking anyway...
robby4570
Member
I am NOT an expert user by any stretch, in fact I only have around 50 hours on the Elite at this point. But I couldn't get to the beach the other day after reading this so I went out into the field in back of the RV Park we live in and I tried out the detector with the coil wire on mt 10 in Tornado wrapped around the shaft, just dangling from coil to control box, and velcroed at the bottom near the coil, run straight up the shaft and then velcroed at the top with the slack coiled up near the handgrip on my "S" shaft. I did not see any noticeable difference on the targets I found, no matter the coil wire configuration. Just my 2 cents worth...
Critterhunter
New member
It's more of a "just in case thing" as to concerns of potential instability problems. Never hurts to take precautions just in case in my book if you even think it might help, just like rubbing a rabbits foot I guess. 
When the box is mounted on the shaft there is no need then to loop the coil cable right before it plugs into the box IMO as it shouldn't be moving or flexing with the box mounted on the shaft, but just the same you don't want it at an odd angle there right at the connector that might put a lot of odd angled stress on the plug IMO to avoid any potential shorts. Even for land hunting I try to keep it tight where it leaves the coil and is "in the air" until it meets the shaft just so I'm not getting any risk of flexing or possible EMI issues too. That's why I coil the cable after it passes to my side of the grip only and only run it straight up the shaft until then secured well with velcro in several places. Just in case of any EMI or stress issues, and coiling it on my side of the grip in the wrist/hand area of the shaft I feel is getting any inductive properties that might eminate out from that coiling as far away from the coil as possible.
One other thing...If you do make the cable somewhat tight where it leaves the coil until it meets the shaft, be sure to not move the angle of your coil or you could possible rip the cable out of the coil. I've got the velcro there somewhat ready to just "pop off" should need be so if I lay the machine down or something and the coil gets pushed out of position it's not torking on the cable where it enters the shaft.
When the box is mounted on the shaft there is no need then to loop the coil cable right before it plugs into the box IMO as it shouldn't be moving or flexing with the box mounted on the shaft, but just the same you don't want it at an odd angle there right at the connector that might put a lot of odd angled stress on the plug IMO to avoid any potential shorts. Even for land hunting I try to keep it tight where it leaves the coil and is "in the air" until it meets the shaft just so I'm not getting any risk of flexing or possible EMI issues too. That's why I coil the cable after it passes to my side of the grip only and only run it straight up the shaft until then secured well with velcro in several places. Just in case of any EMI or stress issues, and coiling it on my side of the grip in the wrist/hand area of the shaft I feel is getting any inductive properties that might eminate out from that coiling as far away from the coil as possible.One other thing...If you do make the cable somewhat tight where it leaves the coil until it meets the shaft, be sure to not move the angle of your coil or you could possible rip the cable out of the coil. I've got the velcro there somewhat ready to just "pop off" should need be so if I lay the machine down or something and the coil gets pushed out of position it's not torking on the cable where it enters the shaft.