Comment The FCC prohibits such devices (Score 1) 1065
Here is an excerpt from the FCC website:
In response to multiple inquiries concerning the sale and use of transmitters designed to prevent, jam or interfere with the operation of cellular and personal communications service (PCS) telephones, the Federal Communications Commission (FCC) is issuing this Public Notice to make clear that the marketing, sale, or operation of this type of equipment is unlawful. Anyone involved with such activities may be subject to forfeitures, fines or even criminal prosecution.
http://www.fcc.gov/eb/Public_Notices/DA-05-1776A1.html
In response to multiple inquiries concerning the sale and use of transmitters designed to prevent, jam or interfere with the operation of cellular and personal communications service (PCS) telephones, the Federal Communications Commission (FCC) is issuing this Public Notice to make clear that the marketing, sale, or operation of this type of equipment is unlawful. Anyone involved with such activities may be subject to forfeitures, fines or even criminal prosecution.
http://www.fcc.gov/eb/Public_Notices/DA-05-1776A1.html