Navigation and Communications Equipment

INSTRUMENT FLIGHT RULES WORKBOOK

CHAPTER ONE

102. NAVIGATION AND COMMUNICATIONS EQUIPMENT

The military has developed a nomenclature system to identify the various types of electronic

equipment in the military inventory. The Joint Communication Electronic Nomenclature System

("AN" system), formerly known as the Joint Army Navy Nomenclature System, was designed so

a designation indicates information pertinent to the equipment. The designation indicates the

designed installation of the gear, the type of equipment, and its purpose. Civilian equipment

designations, however, do not conform to the "AN" system.

A designation that follows the "AN" system begins with the letters AN. This is followed by a

slash and then a three-letter group. The three letters indicate the general nature of the

installation, type of equipment, and purpose, respectively. Following the three-letter group is a

number and possibly a letter which indicates the specific model. An example of a designation

code is AN/ARC-159V. This code indicates that this piece of gear would be a piloted aircraft

radio for communication (receiving and transmitting) (Figure 1-1).

Figure 1-1 Joint Communication Electronic Nomenclature System

Air navigation and communications radios operate over a wide range of radio frequencies which

are measured in cycles per second or Hertz (Hz). A Hertz frequency number can extend into the

billions, so to simplify the writing of such large numbers, a prefix is used. The two prefixes used

to identify the frequency ranges most commonly used in aviation are kilo (k) for 1000 Hz and

INTRODUCTION TO AIRBORNE NAVIGATION AND COMMUNICATIONS

EQUIPMENT AND PRINCIPLES OF OPERATION 1-3