Hi,

I would like to know when they say in this website (http://wiki.backyardbrains.com/Exper...e_Faraday_Cage)
One rule of thumb often used for Faraday cages to prevent transmission is that the holes need to be no larger than 1/10 of the wavelength of the signal

I would like to know what does it really mean out of these 5 options?

a) we need a hole smaller that a square hole whose sides =1/10 of the wavelength to prevent propagation
b) we need a hole smaller than a rectanglar hole which has one side = 1/10 of the wavelength to prevent propagation
c) we need a hole smaller than a square hole whose diameter = 1/10 of the wavelength to prevent propagation
d) we need a hole smaller than a circle hole whose diameter = 1/10 of the wavelength to prevent propagation
e) the perimeter of the hole has to be smaller than 1/10 of the wavelength to prevent propagation

Thank you

 

I would take it to indicate the largest dimension needs to be less that 1/10th wavelength, and that applies to any shape hole, round, square or slot.

 

The hole hase to be less than 1/10 of the wavelength signal,

so like the Example given for a mobile phone signal of 14cm, in a square hole the diagonal has to be less than 14cm,

which give the sides length of 9.8cm.

Most Faraday cages are made from multiple layers of shielding.

 

Does it matter how much of the area is hole and how much of it is metal? I'm thinking of 1/2" mesh wire netting where the hole size is small but most of it is hole not metal.

 

It means the area (square mm) needs to be less than.... The shape does not matter but its best if its synchronized with the shape of the electro magnetic field probably.

The bigger.the holes, the smaller.the efficiency.

 

The hole hase to be less than 1/10 of the wavelength signal,

so like the Example given for a mobile phone signal of 14cm, in a square hole the diagonal has to be less than 14cm,

which give the sides length of 9.8cm.

Wouldn't the diagonal need to be less that 1.4cm?

Does it matter how much of the area is hole and how much of it is metal? I'm thinking of 1/2" mesh wire netting where the hole size is small but most of it is hole not metal.

Obviously the more metal, the better the attenuation.
But if the wire netting has a 1/2" maximum diagonal opening then it will significantly attenuate any signal wavelengths of 5" or greater.