Coil lead length

Hi all,

While changing my coil the other day, I started to wonder about all that excessive coil lead that is wound around the shaft.

I assume it is there for longer shafts or does it serve a purpose?

Would it make a difference in performance if the lead was cut down in length to run straight under the shaft? In most electrical circuits the shorter the cable the better it is.

Any thoughts please.

Yt2...

I believe the lead length is integral to the performance of the coil.

YT2,
Use electrical velco tapes to secure and run the lead in a straight line from coil to the joint along top of lower stick then loop it tightly up to the box. Make sure where the lead passes around the handle to stick bracket the loop is on the out side so if the stick bumps your hip when swinging it doesn't set off a false signal.

Cheers
Nightjar

If your cable is too lose, be sure to avoid it looping as it passes up the shaft.... as this has been said to attract unwanted responses from the coil. I'm going on some old literature there so don't ask me to elaborate. Put simply, winding your cable up the shaft is fine but be sure to prevent loops forming. Another thing that might be of interest is that I recall a more serious prospector writing to 'Gold, Gem & Treasure' magazine some years ago to point out that wrapping the cable UNDER (or OVER) the shaft on the first winding was either right or wrong (I don't honestly remember). He claimed that it was a common mistake (to wind it the wrong way) by many users and it supposedly caused problem with the coil's sensitivity. Perhaps anyone who can remember the article in question can wade in and add more. This was written around the time when the 3000 was the top detector. I can't imagine why the direction would ever be a problem but there you go... different opinions from different folks.

He also said it was important to reduce stress to where the coil plugs into the socket on the body of the detector. He suggested a single loop be made in the cable, just between the grip handle and the control box socket. This was more for the continued integrity of the detector and the coil rather than an issue that might interfere with the normal use of the detector.

Gday


I usually make the first loop over the top of the shaft, making sure to leave enough cable in the loop so that I can move the coil about without putting any stress on the point where it enters the coil, I have a velcro strip about 8 to 10 inches from the coil that it the first anchor point, from there the cable is wound securely along the shaft to the plug.

A mate told me the same thing about the lead having to go under or over the shaft but like Nero I cant remember which way it was, I remember thinking at the time though why it would make any real difference, and the only thing I could think of was if it was put under the shaft it would be closer to the coil and in the coils field so that the coil as we know becomes less sensitive if it has something metallic close to it, and this is why the fibreglass shafts are used also, for the same reason as the coil can pick it up, using this logic then I would have to guess that the lead should be wrapped over the top of the coil on the first loop????, keeping it a bit futher away from the coils field.

About the coil cable length, I would assume that the length of the cable would be important, firstly so it can be wound securely along the shaft to minimise any movememt that causes falsing, but also it is probably a measured length that gives the right amount of conductance or resistance or whatever the correct term is, so I am sure if the manufacturers could use less cable to make the coil lighter or more cheaply then I would have to say that they would have done so by now.

Where the cable plugs into the control box needs to be secure but not tight or pulling on the socket so that part I feel is true also, you can test this for yourself, if while you have the detector going you give that plug a bit of a wiggle you will make it sound off, sometimes if you forget to properly tighten the plug into the socket you will also make the machine a bit noisy and touch sensitive, any movement from the plug area will do this and will react in a similar way to when the cable is damaged where it goes into the coil body, if your machine seems a bit erratic switch it off and check the security of the plug and cable windings, very often you will find thats what the problem will be.

cheers

stayyerAU

Hi YT2,

You could be on to something there. It would change the inductance a little but I believe you would get a gain in performance. Why not give it a try and report your findings. I've noticed nugget finder leads are getting shorter so there could be something in it.

Firstly thanks guys for the tips on winding the cable, up until now I have just done, now I will take a little more pride in my winding.

StayyerAU says - so I am sure if the manufacturers could use less cable to make the coil lighter or more cheaply then I would have to say that they would have done so by now.
that’s a good point.

Undertaker - not sure what you mean by "inductance" as I am just a train driver, but I figure less cord means, less metal near the coil, less chance of false signals due to cable movement if they come loose and possible more power.
Before I start hacking, I will ring a coil manufacture and see what they say.

Stay tuned Yt2...

Look at:

http://www.coiltekmanufacturing.com.au/faq.html#q10

and

http://www.coiltekmanufacturing.com.au/faq.html#q9