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Emission Measurements of a Contraband Wireless Device Jammer at a Federal Prison

Sanders, Frank H., Johnk, Robert T., Drocella, Edward F.

This report describes emission spectrum and time domain measurements of a contraband wireless device micro-jammer that was operated temporarily in four Commercial Mobile Radio Service (CMRS) bands at a Federal Correctional Institution (FCI) at Cumberland, Maryland. The four jammed CMRS bands were between 730 MHz and 2.155 GHz. The micro-jammer targeted CMRS service indoors, in a single medium-security prison cell. Spectrum measurements of the jammer emissions were performed at two places inside the targeted prison cell and at two non-targeted nearby locations outdoors. Jammer emission measurements were performed at each location with multiple measurement bandwidths and detectors across a frequency range of 300 MHz to 4.34 GHz. Measurements at each location were performed twice, with the jammer device on versus off, so as to show the relative power levels of the jamming signal versus the ambient CMRS signals at each location. Aggregate emissions from multiple micro-jammer devices such as would be required to cover an entire prison facility were not measured. Jammer emissions are presented in units of power per unit bandwidth in measurement system circuitry; a table for conversion of those data to units of incident field strength in space is provided.

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