Thanks for your responses. The link I posted was an example of all I could find on the web, not my personal preferences, but you get the idea.
I tried calling my cell phone in my microwave and had no signal; interesting, perhaps the 'tyre kickers' way to shop for a safer microwave!
This is part of a larger experiment and I'm only loosely drafting the framework. Current considerations are does it work or would it be possible, and how would you measure it?
It's really to see how much of the surrounding environment is saturated by modern radio waves (since the first broadcast on December 24, 1906 from Brant Rock), and look at how much effort is required to shield it. Whether it's pointless or redundant isn't the point in this instance, it's a controlled experiment to see if it's possible and measure the difference between them.
Disappointingly, a frequency is a measurable dimension and depending on wave frequency and mesh size, some will fit through larger meshes and be stopped by smaller ones accordingly. Besides a metal box, the alternative is to stop all radio waves above and below the visible range of the Electromagnetic Spectrum.
Or click here for a more enjoyable version.
With emphasis on the modern waves, it would be interesting to better understand the frequencies in use above, from 1900 to 2010.