Lead... Does lead (atomic element #82) block all electromagnetic/radio/x-ray/microwave/etc signals? All frequencies or only a certain range? What doesn't it block? Is there any type of transmitter that when put into a lead box will still be able to transmit and receive signals? Is the thickness of the lead a factor? Is there anything else i need to know about lead and radio waves? If anyone studied this subject or knows about it, can you please enlighten me? Also, if anyone knows where i can get one, please post a link.