I keep hearing that for Faraday cages but its not clear to me why.
Why should it be grounded?
The cell signal in the Faraday cage causes a mirror signal on the cages inner surface and the cage’s conductivity ensures that the potential is zero elsewhere in the cage.
Why do I need the ground? Is it a consequence of not having a perfect conductor?
Does it though? At what frequency? In the limit of f=DC this is trivially not true.
Also, if that were the case, an airplane couldn't be made into a Faraday cage.
Also, the cage+Earth system would itself be an antenna.
If you need ground for a topologically imperfect cage, maybe… but I doubt it.
I think (but I don't know!) this is like the legends surrounding engine torque car guys believe. Electrical engineers putting everything to ground because they got burned
Why should it be grounded?
The cell signal in the Faraday cage causes a mirror signal on the cages inner surface and the cage’s conductivity ensures that the potential is zero elsewhere in the cage.
Why do I need the ground? Is it a consequence of not having a perfect conductor?