Spectrum Engineering

The possibility of allowing shipborne navigation radars within the 9300-9320 MHz band is being considered within Study Group 8 of the International Radio Consultative Committee (CCIR) and within the United States preparation for the 1987 Mobile World Administrative Radio Conference. The impact this would have upon beacon systems used within the aeronautical radionavigation service is of concern. The report provides the background, equipment characteristics, and an analysis of the potential interaction between the shipborne radars and the aeronautical beacon systems.

Before 1987 no commercial trunking systems were available in any Govenment or non Government band below 800 MHz. This study examined the application of trunking to the Government band 406-420 MHz. As a result of this study and subsequent discussions with industry, commercial trunking systems were developed for the Government.

This report documents an effort to measure the operational and performance characteristics of radios equipped with the Data Encryption Standard (DES), as applied to government land-mobile operations. The purpose of these tests was to compare selected operational and performance characteristics of the digital (or guarded) mode of operation with those of the analog (or clear) mode of operation for each radio under test. The measurement results are discussed relative to spectrum management issues involving the use of spectrum allocated to the Federal Government fixed and mobile services and the corresponding rules of use. This measurement effort is the first phase of an on-going program to investigate the effect of using digital modulation schemes in a predominantly analog land-mobile environment.