® 
of the SENSITIVITY control and labelled PUSH TO RES To reset, hold 
the reset switch down for about ten seconds. If the automatic switching 
unit fails to reset, reduce the SENSITIVITY control very slightly (counter- 
clockwise) end repest the resetting. 
38. For routine operation, pull the sliding drawers in racks two and three 
out to the stopo Turn the SPEEDS clutch adjustment marked WRITING on the 
PL recorder in the second panel from the top of Rack 2 to the FAST position, 
and turn the pApre iai/suc, clutch adjustment beside it to the 5/1 position. 
These adjustments will give a paper tape speed of Smm/sec, 
39. Turn the "Mirroyhone"™ magnetic tapes recorder SELECTION switch on the 
upper right of the bottom panel of rack two to the RECORD position. Turn 
the sig. vy. ¢, switch just to the left of the magnetic tape recorder switch 
about two thirds mactimum clockwise, ‘Turn the 3%G V.C, switeh just below the 
mapnetic tape recorder switch as far as it will go clockwise. 
40. Rack 3: It is assumed’ that the chronometer has already been placed in 
operation. Adjust the 77 ; ¢lutch on the PL graphic level recorder to 
the SLOW position and the PAPER Mu/S5h0. clutch to the 50/10 position. 
These adjustments will provide a paper speed of 10 mm/sec, 
41, Even though the magnetic tape recorder in Rack 3 may be in stand-by 
operation and not running, adjustments should be made to ready it for 
operation the moment it is needed, Turn the SHLECTOR switch on Mirrophone 
#1 in Rack 3 to the PEGoRp position. If it is a Caltron recorder turn the 
3KC VG, completely clockwise; if it is a Western Electric Mirrophone, 
adjust the SiG, ¥. ¢.to about two-thirds maximum (clockwise). The Caltron 
recorder is then placed in operation by turning its SiG, ¥, ¢,to about two- 
thirds maximum, and the Mirrophone is started by turning its 3KC V0, come 
pletely clockwise, 
42; The station is now ready to receive, record, and time the arrival of 
a ptenel.. 
OPERATING THE SCFAR MUTPMENT WHEN A SIGNAL IS RECEIVED 
43, All volume controls snd variable pads have numbered dials, It is very 
Smportant that a complete log of all settings be kept for each signal that 
is received, together with the name of the operator in charge at the time. 
This dnformatdon is necessary for the evaluation of SOFAR data and will 
facilitate the making of circuit adjustments. Fig. III gives the headings 
which should be used, Data sheets drawn up according to the pattern of Fig, 
III should be on hand at all times, 
4k, As soon as the signal strength on the arrival of @ sound channel signal 
rises above the background noise the Automatic switching unit will fire. 
(aoe 
