Chapter 7 — COMMUNICATIONS EQUIPMENT AND OPERATIONAL PROCEDURES 



civil aviation. The FAA also provides and op- 

 erates a communications system for the col- 

 lection and dissemination of meteorological 

 information required by the National Weather 

 Service. The National Weather Service, which 

 serves the general public, determines the form 

 and content of meteorological information to be 

 scheduled on the FAA fixed weather communi- 

 cations circuits, and the extent of distribution 

 required. The civil weather communications sys- 

 tems serving the various U.S. meteorological 

 agencies are the FAA Weather Teletype Serv- 

 ices A, C, and O. In addition, the National 

 Facsimile Network and the High Altitude Fac- 

 simile Service are under the control of the 

 National Weather Service. 



The Modernized Weather Teletypewriter Com- 

 munications System (MWTCS) consolidates the 

 circuit control and relay functions of Services 

 A, C, and O into a single Weather Message 

 Switching Center (WMSC) at Kansas City, Mis- 

 souri. These functions are performed auto- 

 matically by a group of electronic computers, 

 which are combined to operate as a real-time, 

 store-and-forward communications switch. All 

 Service A and C circuits extend directly into 

 the WMSC. Certain of the Service O circuits 

 also extend directly into the computer switch, 

 while others, from overseas points, pass through 

 the Aeronautical Fixed Telecommunications 

 switch which is collocated and interconnected 

 with the WMSC. Computer-to-computer links 

 provide for the exchange of data between the 

 WMSC and the National Meteorological Center 

 at Suitland, Maryland, and between the WMSC 

 and the USAF Automated Network at Carswell 

 AFB, Texas. For a more complete description 

 of the highly modernized circuitry used in this 

 system, refer to the Federal Aviation Adminis- 

 tration Flight Service Manual 7110.10( ) chapter 

 4. 



WEATHERVISION SYSTEMS 



station. Additional weather briefing information 

 is obtained by pilots via two-way radio com- 

 munications. 



At the present time there are two primary 

 weathervision systems in operation throughout 

 the Naval Weather Service. The first and oldest 

 is the AN/GMQ-19A(V) and the newest is the 

 AN/GMQ-27(V). Both sets are designed as a 

 closed circuit television system and two-way 

 audio system. These two systems are briefly 

 discussed in the following paragraphs. 



AN/GMQ-19A(V) AND AN/GMQ-27(V) 

 WEATHERVISIONS 



The consoles of the Weather Television Sys- 

 tem AN/GMQ-19( ) currently in use and its 

 replacement, Weather Television System AN/ 

 GMQ-27( ), are illustrated in figures 7-18 (A) 

 and (B). 



There are a number of modifications which 

 have been incorporated into the newer AN/ 

 GMQ-27. These changes however are primarily 

 improvements in solid state circuitry, camera 

 design, etc. Maintenance procedures performed 

 by contract or station electronic personnel have 

 changed to some degree. The minor preventive 

 maintenance required of the Aerographer's Mate 

 remains relatively unchanged and will be dis- 

 cussed later in this section. The system ar- 

 rangement and related functions have remained 

 relatively stable. 



All components of the central weather sta- 

 tion are mounted within or on the metal cabinet 

 assembly. Two rear access doors are provided 

 which are hinged and will lift off. The light 

 table on the right side of the console contains 

 six fluorescent lamps beneath a glass plate 

 and diffusion glass cover. Two 150-watt flood- 

 lights are provided for opaque illumination when 

 not using the light table for transparent illumina- 

 tion. 



A great development in communications- 

 meteorology with which the Aerographer's Mate 

 should be familiar is the weathervision system. 

 This is a closed circuit wire transmission 

 television system for transmitting weather in- 

 formation instantaneously to several remote lo- 

 cations simultaneously. A television camera in 

 the station's weather office transmits weather 

 maps and other meteorological information to 

 receivers placed at various locations on the 



The camera assembly, with its component 

 parts, is mounted rigidly to the top of the 

 cabinet over the light table. A covered housing 

 protects the lens zoom and focus motors. 



The recorder is located just above the video 

 screen. It is a single channel, 24 hour, magnetic 

 tape recording and reproducing unit designed 

 to record from either a microphone, a telephone, 

 or a direct line. It will record continuously 



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