Chapter 5 — CLOUDS AND VISIBILITY 



8. BRIGHTNESS control. Adjust the bright- 

 ness of the RVR display. 



Make sure that all cables are connected 

 properly. Turn the BRIGHTNESS knob fully 

 clockwise. The display screen should now be 

 illuminated. The observer should wait 2 minutes 

 before observing the displayed digits. 



The power requirements for the Converter- 

 Indicator Group are 115 + 10 volts ac, 60 

 hertz, with a three-prong outlet providing 1.0 

 amps for the Signal Converter and a two-prong 

 outlet providing 0.2 amps for the digital Display 

 Indicator. 



Test Equipment 



Maintenance specialists who have been 

 trained and are familiar with this equipment will 



perform the necessary tests and operational 

 and field maintenance on this equipment. More 

 details concerning operation and maintenance of 

 this equipment are contained in the equipment 

 manual which should accompany the equipment. 



Office Installation 



The Transmissometer AN/GMQ-10 ( ) and 

 Converter-Indicator OA-7900A/GMQ-10 ( ) 

 readout units are generally mounted in a stand- 

 ard 19-inch communications rack in any 

 combination. This installation may also combine 

 the Cloud Height Set Recorder RO-121/GMQ- 

 13 ( ) without its stand in order to conserve 

 space. (See figure 5-22.) 



NOTE: Changes to all column numbers and 

 entries on NWSC Form 3140/8 were received too 

 late for inclusion in this manual. Where errors 

 in column numbers appear, refer to the U.S. 

 Navy Supplement to FMH #1, Chapter 13, Marine 

 Aviation Observations for the most recent ampli- 

 fying instructions. 



101 



