How to make a cell phone dead zone box?

To test an application under conditions where the carrier's signal drops (someone driving into a tunnel for instance), I'm curious if there's some sort of box available (or easy enough to make) that I could put the phone into and close it, effectively blocking out the carrier's signal and dropping the call.

Thoughts anyone? Thanks! -Chris

NachoMahma6 years ago
(Otherwise known as a switched-off microwave oven...)
bennett468 (author)  NachoMahma6 years ago
You're awesome. Thank you!
bertus52x116 years ago
A box with Alluminium foil inside.