Another PI coil shield method.

[6666]

I have just opened a length of outside cable tv cable to see whats inside, the shielding could be worth a try, not sure what metal it is yet because the inside of the cable has this thick sticky goo which has gunked it all up, need to find a way to clean it off.

[mohandes]

KT, Mick is still right about ground capacitance. I didn't specifically spell this out in the book but it is one of the problems shielding helps minimize. Sorry if you don't understand this, so perhaps it's best to let it go.

hi
this shielding is ok or no ??tinned copper wire OK or this tiny foil ??guide me
regards

[Carl-NC]

KT, Mick is still right about ground capacitance. I didn't specifically spell this out in the book but it is one of the problems shielding helps minimize. Sorry if you don't understand this, so perhaps it's best to let it go.

[kt315]

sorry Mickstv. I have not possibility to post complete text because the book is copyrighted.

[mickstv]

How about you post up that complete section that you have purposely blurred out, so everyone can see/read the whole story.

[kt315]

[kt315]

thank you Carl. I suggest for the people to open 246 page of INSIDE THE METAL DETECTOR and read ELECTROSTATIC SHIELDING chapter.

[Carl-NC]

KT, Mick is right about ground capacitance.
KT, you are also right about electrostatic charge.

[kt315]

Wow, you're a trip, Mickstv.

[mickstv]

ok. correct. where you see the capacitance of ground? WHAT it is?

If an unshielded coil is moved around, the capacitance between it and the ground or other objects changes, this causes a response. The shielding isolates the coil from the ground.

[kt315]

ok. correct. where you see the capacitance of ground? WHAT it is?

[mickstv]

NOT NOT AND AGAIN NOT!!!!!
coil shield purpose is TO DECREASE of THE INFLUENCE of ELECTROSTATIC FIELD OF FARADEY BETWEEN THE COIL WINDINGS AND GROUND, to protect FROM ELECTROSTATIC CHARGE

My post was correct.

Please do not post in this thread again, if you plan to continue shouting i.e. "using bold uppercase and stupid emotions" that is just bl00dy rude and stupid.

[kt315]

Coil shield purpose is to remove ground capacitance.

NOT NOT AND AGAIN NOT!!!!!
coil shield purpose is TO DECREASE of THE INFLUENCE of ELECTROSTATIC FIELD OF FARADEY BETWEEN THE COIL WINDINGS AND GROUND, to protect FROM ELECTROSTATIC CHARGE

[mickstv]

hi
my English not well . i see your PDF and read your post, you say do not increase depth or sens but remove ground cap ???
and i dont understand how shielding the coil use , have 3wires in PDf , black , and two yellow, where them connection ?
i want use use braid tinned copper , and now i see your new idea , so if you say us more explain more better.
regards

Coil shield purpose is to remove ground capacitance. Some shielding methods reduce sensitivity, but this one doesn't reduce sensitivity.

The black wire is shield ground, the other two wires are coil wires. You connect the black to one of the coil wires, this connection point then becomes the coil common wire i.e. it connects to your battery the other single coil wire goes to the mosfet.



You need to select a braid material that isn't detected by your detector when waved over the coil.

[mohandes]

I'm going to order some more litz wire in the next couple of weeks. Once i get it I'm going to try a modified version of the method from my first post, if it works I'll make another PDF so others can try it.

hi
my English not well . i see your PDF and read your post, you say do not increase depth or sens but remove ground cap ???
and i dont understand how shielding the coil use , have 3wires in PDf , black , and two yellow, where them connection ?
i want use use braid tinned copper , and now i see your new idea , so if you say us more explain more better.
regards