364 



DIRECT MEASUREMENT TECHNIQUES 



TRANSDUCER 



AMPLIFIER 



TRAINING 

 GEAR 



RELAY 



AMPLIFIER 



OSCILLATOR 



TRAINING 

 CONTROL 



-► REPEATER 



MODULATOR 



OSCILLOSCOPE 



PELORUS 



---♦ REPEATER 



LOUD SPEAKER 



CHEMICAL 

 RECORDER 



GYRO COMFWSS 



REPEATER 



■*- ELECTRICAL CONNECTIONS 



•- ELECTROMECHANICAL CONNECTIONS 



Figure 1. Experimental arrangement. 



Division of War Research at the U. S. Navy Elec- 

 tronics Laboratory, formerly the U. S. Navy Radio 

 and Sound Laboratory, San Diego, California 

 [UCDWR]; Columbia University Division of War 

 Research at the U. S. Navy Underwater Sound 

 Laboratory, New London, Connecticut [CUDWR- 

 NLL]; Woods Hole Oceanographic Institution, 

 Woods Hole, Massachusetts [WHOI]; and the 

 Underwater Sound Laboratory, Harvard University, 

 Cambridge, Massachusetts [HUSL]. In addition, 

 various groups at Fort Lauderdale, Florida, have 

 also made measurements of this nature. Widely vary- 

 ing procedures and techniques have been employed 

 by these groups. 



21.2.1 



San Diego 



Most of the direct measurements by UCDWR 

 have been made off the coast of California aboard the 

 USS Jas'per (PYcl3), a converted 135-ft yacht built 

 in 1938, which echo ranged on various S-boats or 

 occasionally on new fleet-type submarines. Square- 

 topped signals from 0.5 to 200 msec long were sent 

 out, usually at a frequency of 24 kc and sometimes 

 at 45 or 60 kc. Early trials used a QCH-3 magneto- 



strictive transceiver driven at a frequency of about 

 24 kc ; ^ a few measurements were also made with an 

 experimental model of frequency-modulated sonar 

 gear.' Later runs employed standard JK or QC trans- 

 ducers * or specially designed equipment.' 



Most of the echo-ranging equipment was installed 

 in the wardroom of the Jasper; a schematic diagram 

 of the installation is shown in Figure 1. A pelorus, an 

 open sighting device attached to a dial and employed 

 in determining bearings, was mounted topside on the 

 flying bridge. An observer visually trained this pe- 

 lorus on a float towed by the submarine, and the rela- 

 tive bearing of the pelorus was relayed to a repeater 

 dial in the wardroom below. Here, another observer 

 followed the relative bearings of the pelorus and 

 trained the transducer on them; obviousl}^, the beai- 

 ing accuracj' obtainable in this manner was not very 

 high. Then the echoes received by the transducer 

 were amplified and fed into a cathode-ray oscilloscope 

 to be photographed on continuou.sly mo^'ing film by 

 a high-speed camera. The echoes were also usually 

 heterodyned and monitored over a loud speaker, and 

 supplementarj' records were made on the sound- 

 range recorder, where the keying interval was con- 

 trolled manually as the range changed. 



