NCJ Number
101845
Date Published
1986
Length
12 pages
Annotation
This document reports on an exploratory study to determine the susceptibility of electronic sirens to interference from typical communications equipment such as the transmitters and antennas of a law enforcement vehicle.
Abstract
Tests were performed using five sirens and communications equipment at frequencies representing the frequency bands of 25 to 50, 150 to 174, 400 to 512, and 806 to 866 MHz. The sirens were mounted on top of a vehicle equipped with transmitters and roof-mounted antennas and subjected to levels of field strength generated by mobile transmitting equipment having output levels up to 100 W. The control units of the sirens were also subjected to various levels of field strength inside a transverse electromagnetic cell or an anechoic chamber to determine their susceptibility to electromagnetic fields. Test results indicated that variation in siren output was not due primarily to the susceptibility of the control unit. Photographs, tables, and 8 references. (Author abstract modified)