[Dennis]

Hi
I have have bean running my Garret sea hunter mark 2 at the beach for some time, the volume level has been set at 3-4, this allows me to have more audio on deeper objects. But then a constant tone running in the background, looking at the magnetic field that runs around the mono coil a solution must be found. Using my scope and a dummy coil consisting of ten turn of 18 SWG wire I can detect the magnetic field, once this was plotted at varies angles in different positions a basic diagram was compiled.
The pulses can be seen coming up on the screen. By varying the coil angle from 45 -90 degrees the inductance can be reduced in the dummy coil. What does this mean, the sea hunter coil comes with a long cable, one must allow this to be wound around the long arm leading to the coil.
I now run the sea hinter at a volume level of 6-7, this now allows me to hear even tones that where not able to be heard early, The key to solving this is shown in the picture, Run the coil cable parallel to the plastic arm and strap it up, I would suggest cover the cable with some plastic tubing that is split to protect it from damage, this I will still do.
Why does this work? the magnets lines of force are now cutting the cable at almost 90 degrees, and there fore very little inductance takes place in the cable leading up to the control box. Keep it vertical for as long as possible to get out of the magnetic field of the coil.
My machine is totally quite with no tone running in the back ground, only a tone when a target is located. (this may vary from machine to machine). Further to this one can add a ferrite toriod on the cable to reduce all external interference going up to the control.
head.
THIS WILL APPLY TO" ALL" DETECTORS SO PLEASE TRY IT AND HOPE FULLY IT MAY HELP YOU IN SOLVING SOME FALSIFYING TONES THAT YOU HEAR. GOOD LUCK.

[Paul van Heerden]

Thanks Dennis. I will try this with my CS4PI and see if there is a difference

[Allen]

Geez .. with the volume control turned that high you are going to kill yourself with the first solid hit you get ? How do you overcome this ?  Catch 22. With the background noise floor reduced to near zero it should not be necessary to up the volume much as even the weakest signal will be above the noise floor.

I have found on my GSH 2 and also the EuroAce is to tape down the coil feed to restrict any cable movement near the coil as this movement would also create falsing. Going to try your suggestion and see  how much improvement I get. Any bit helps.

[Dennis]

Hi

When when working in waist deep water the chances of getting a hit every meter are slight, so the chances of hearing some faint signal is good, found a ring this morning in deep water it was the only tone I got, but it worked for me. I do not run normally at this level but had to try it to prove a point with the sea hunter.

[Paul van Heerden]

Is it not good to hear the nulls as well? If there is no sound, how do you hear the nulls?

[Tony Curnick]

He'll thanks for sharing this bit of wonderful info on the day I am leaving for home Dennis... But it makes sense

[Dennis]

Hi Paul
The sea hunter has a different tone generation to the standard detector, it is quite and a tone is heard or generated when one comes in contact with a ferrous object, using the sea hunter and running it at low volume just with a side tone in the back ground can be irritating, the way the wire is placed this tone can be a lot quite in fact not heard at the same setting, I am currently using a higher level on the audio setting than use to be before the side tone is heard, contrary what some people say, I did mention that this will vary from detector to detector.
Tony let us know if you sense the difference in the sensing with the cable running vertical for the entire length of the plastic lower shaft. I am keen to hear the opinions of there detectors out there. I am very happy with the improvement that has come about from this.
Happy hunting.

[Allen]

How the excess coil cable should be wrapped is an age old debatable subject on the technical metal detecting forums, ie wind clockwise, counter clockwise or straight up the shaft ?
Very much like how a toilet role should be hung  .........  end over or end under ?

I have tried all methods with no change as to background noise levels. What does make a difference is that whatever you do, it must be wrapped tight with no movement, just leave a slack loop at the bottom to allow for coil movement.

Pic of how I wrap my Sea Hunter (showing duct tape here ....normally it will be held in place with elastic and Velcro.)

[SCRUcc]

Fully agree with you Allen, been swinging the mk2 for more than eight years on the beach now, just keep it tight as you say....luckily configured mine like that right from the start and have never had the problem...

[Tony Curnick]

Will try it out as soon as I am back at the coast,I did notice that my SH was messing around on the threshold after a dumb waiter knocked it of a chair,could have just been the cord.. .