NCJ Number
19454
Date Published
1973
Length
36 pages
Annotation
THIS STUDY EVALUATES THE EFFICACY OF AN AUTOMATIC DIRECTION FINDER (ADF), TUNED TO COMMERCIAL AM BROADCAST STATIONS, TO LOCATE A HIJACKED TRUCK IN AN URBAN ENVIRONMENT.
Abstract
THE MEASUREMENTS TAKEN WITH THE ADF IN A TEST TRUCK INDICATED THAT THE ERRORS WERE GREATER THAN AN ACCEPTABLE LEVEL. MEASUREMENTS WERE MADE AT SEVENTEEN SITES, WHICH RANGED IN CHARACTER FROM DOWNTOWN, WITH HIGH-RISE BUILDINGS, TO SOME RELATIVELY UNCLUTTERED FLAT AREAS. THE LEVEL OF ERRORS CORRELATED WITH THE COMPLEXITY OF THE ENVIRONMENT AND INDICATED THAT BUILDINGS, POWER LINES, AND OTHER POTENTIAL RERADIATORS STRONGLY INFLUENCE THE ELECTROMAGNETIC FIELD, EVEN AT WAVELENGTHS AS LONG AS 500 METERS. ON THE BASIS OF THESE TESTS, IT IS RECOMMENDED THAT THE USE OF A TRUCK-INSTALLED ADF BE ELIMINATED AS A CANDIDATE FOR HIJACKED TRUCK LOCATION. (AUTHOR ABSTRACT)