MINTEMNCE MANUAL FOR THE EXPERIMENTAL 

 LONG DISTANCE' sbu^iD^NGJNCrmUIBffiTsOFAR) 



SCOPE 



1 Thi3 report provides detailed instructions for performance tests and 

 maintenance work on the receiving, recording^ and timing equipment of a 

 station in an Air-Sea Rescue network,, It supplements USL Report No, 55* 

 "Experimental Long Distance Sound Ranging Equipment (SOFAR) - Installation 

 and Operating Notes „"_ In addition, it provides technical data on the station 

 components , 



INITIAL ALICE 



2, Before the SOFAR equipment vd.ll operate reliably a number of performance 

 tests must be made (see USL Report No s 55 j> paragraphs 26 and 27) „ These 

 tests are described in the following sections, each one of which also pro- 

 vides the technical and maintenance data required for its part of the equip- 

 ment. It may be necessary to repeat these tests during daily operation 

 when servicing of the station components is required or when a defective 

 unit is replaced* The Maintenance Manual, together with electronic test 

 equipment, should therefore be available to station personnel at all times, 



3° Before undertaking the preliminary alignment, operating personnel should 

 study Figs o 50 and 38 to familiarise themselves with the location and function 

 of the station component s. They should carefully note the system layout and 

 the path of an incoming signal through. the receiver-amplifier to the recording 

 and timing equipment „ 



AMPLIFIER CHANNELS 



Description 



4, Amplifier channels numbers 1 and 2 are located on the two. upper shelves 

 of Rack 1 (Fig, 2), They are identical and each consists of a WoE„ 120B 

 preamplifier (Fig, 39) working into a 40-db attenuator. The attenuators 

 are controlled by knobs on the left sides of the two upper front panels, 

 one knob labeled and the ether labeled 



„ Each attenuator is followed by a W.E. 121A line amplifier (Fig, 

 40) o The amplifiers are shock-mounted and should float freely '„ In opera- 

 tion, one of the channels amplifies the signal from the hydrophone before 

 it is applied to the recorders and the other channel is in stand-by. 



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