3. EQUIPMENT AND INSTRUMENTS 



75 



Figure 24.— Installation of EDO 185 (AN/UQN) 

 echo sounder. 



Complete instructions for operation and 

 servicing the equipment are contained in a 

 manual furnished by the manufacturer. 



A single phase power source of the 500 

 watts at 110 volts, 60 cycles is required to 

 operate the EDO-185. The sounder draws 

 only 330 watts when operating, but addi- 

 tional power is required to start the motors. 

 The instrument is calibrated for a sound 

 velocity of 800 fathoms per second at 60 

 cycles. A constant frequency must be main- 

 tained to provide accurate soundings. The 

 drift from 60 cycles should not exceed 0.2 

 cycle at any time. 



In order that a constant frequency power 

 source may be assured, the Coast and Geo- 

 detic Survey provides for each installation 

 of the EDO-185 a 60-cycle frequency stand- 

 ard which drives a power amplifier of suffi- 

 cient size to operate the scanning motor. 

 On early models it was necessary to make 

 some changes in the wiring to use the 

 constant frequency power source, but later 



models provide connecting posts and a two- 

 position switch for easy adaptation. The 

 motor is started on the uncontrolled ship's 

 power and is switched to the controlled power 

 for operation. Failure to folloiv this proce- 

 dure in starting the recorder can result in 

 damage to the equipment. 



3-78 Operating characteristics. — The 



EDO 185 records soundings on Type L 

 Teledeltos paper which has a scale width 

 of approximately 8 14 inches. The paper is 

 supplied in 100-foot rolls. The equipment 

 was designed to provide a paper speed of one 

 inch per minute on the 600-foot scale; 10 

 inches per hour on the 600-fathom scale, and 

 1 inch per hour on the 6,000-fathom scale. 

 As used on Coast and Geodetic Survey ships, 

 the gears have been changed to double this 

 paper speed. 



The accuracy of recorded soundings is a 

 function of the constant frequency (3-77) 

 and the speed of the stylus. At the cali- 

 brated speed of sound, 800 fathoms per sec- 

 ond, the stylus should travel from the zero 

 line to the 600-fathom line in 1.5 seconds on 

 the fast speed, or from the zero to 6,000 

 fathoms in 15 seconds. The stylus speed 

 should be checked at the beginning of the 

 season and once or twice during the season. 

 This speed is a function of the diameter and 

 speed of the drive pulley and should always 

 be checked if a new pulley is installed. 



The stylus belt speed can be measured by 

 the following method: Release the fatho- 

 gram paper drive so that the paper will re- 

 main stationary. Cut two small slits in the 

 paper, one at the zero line and the other at 

 the bottom line of the graph. Apply a small 

 voltage to the chart plate and stylus needle 

 in such a manner that electrical contact 

 will be made as the needle crosses each 

 slit. The system should be hooked to a 

 chronograph and the period between con- 

 tacts measured against time as marked from 

 a mean time break-circuit chronometer. The 

 speed of travel can be measured on either 

 the 600- or 6,000-fathom scale. 



If desired, the recording mechanism can 

 be turned off and the depth viewed on a 

 3-inch cathode-ray tube. The timing circuits 



