Faraday cage

[John Fenna]

It would appear that the OP only wants to block phone and walkie Talkie signals to avoid unwanted calls: I just switch my comms off with the integral switch ..... it works a treat!

 

[SCOMAN]

Much more impressive is watching some devil getting the b@llocking of his life from a Warrant Officer who until then I had thought so benign! Topped off with a senior Navel officer heard to say "What the 7uck do you fly boys do in there!!!"

A fair question likely. ;-)