shield foil thickness

[simonbaker]

I have some 3M Scotch 3311 foil to use for shielding coils.

It is 2 mil thick.

Seems like more thick than needed for capacitive shield.

What thickness do people recommend for shield foil?

Does too thick foil make problems?

Regards,

-SB

[mikebg]

Simon, the problem of thick shield is only one - you can not adjust exact induction balance. With bad balance, you should operate at increased minimum of AIR signal, that means the gain of RF amplifier is more limited because always there is signal in its output.
Test with your machine if it detects as target a piece of shielding foil. Watch signal in output of RFA and try to adjust balance with two cores: a ferrite and a piece aluminium foil placed on coil housing. If adjustment with cores is succesful, then your shielding is not so bad.

[simonbaker]

Simon, the problem of thick shield is only one - you can not adjust exact induction balance. With bad balance, you should operate at increased minimum of AIR signal, that means the gain of RF amplifier is more limited because always there is signal in its output.
Test with your machine if it detects as target a piece of shielding foil. Watch signal in output of RFA and try to adjust balance with two cores: a ferrite and a piece aluminium foil placed on coil housing. If adjustment with cores is succesful, then your shielding is not so bad.

Thanks, I'll try that.

-SB