at 
= 5,3 
Sensitivity and camera magnification, a capacitance bridge for measuring 
cable capacitance when the Q=-step was not used, standard frequency sources 
for the time calibration of the sweep or film speed depending on whether 
still~film or rotating-drum cameras were used, electronic sweeps for still- 
film cameras, and the necessary cameraSe 
All of this equipment was efficiently housed in the electronics cabin 
built into the hold of the RELIANCE, the plan for which is show in Fig. 2. 
The arrangement of the various electronic components is shown in Figs. 12, 
13, and 1. The panels forming the cabin bulkhead behind this equipment 
were removable to allow minor servicing and the changing of patch-cord 
connections (Fige 15). 
(i) Master control, For routine shooting, where many channels are 
used, the length of time and large chance for error involved in connecting 
and disconnecting gauge lines, steppers, frequency sources, sweeps and 
tripping devices into the oscilloscopes make it imperative that some form 
of master control panel be used [17]. With this master control panel all 
switching operations were made by turning a single knob. Positions were 
available for voltage step, Qe-step, time calibration, and firing, as well 
as for resistance and capacitance tests of cablss. The circuits were inter- 
locked so that it was not possible to fire the charge wnless the master con— 
trol panel was in the firing position. A meter was available on the master 
control panel by which the various cable resistances could be measured by 
turning a selector switch. There was also space in the back of the panel to 
provide for the plug-in cable compensation uetwork. 
Ga) Oscilloscope and amplifiers, The Dumont 208 oscilloscopes were 
used as the recording equipment with certain modifications, A low-impedance, 
compensated, step attenuator was inserted to give reproducible amplification 
settings. The frequency-compensation circuits were modified so that the 
oscilloscope had a frequency response flat to within ae percent from about 
5 eycle/sec up to 300 ke/sec, with no rise at 00 ke/sec, The accelerating 
voltage of the cathode-ray tuhe was increased enough tc allow writing speeds 
up to 3 in./msec. Beam brightening and positioning could be controlled ex= 
ternally, and a single, repeating single, or continuous sweep was provided 
externally. The sensitivity range was from 5 v/in, deflection minimum up 
to 50 mv/in. deflection, The deflection-voltage ratio agreed to within 1 
percent up to 1-1/2 in, deflection. Type 5LP5 tubes were used originally 
and later 5CPS tubes were used, These tubes had short enough persistance 
so that they could be used successfully with rotating-drum cameras. 
(iii) Voltage stepper. To calibrate the amplifier sensitivity and the 
magnification factor of the camera, it was necessary to place a known volt= 
age on the plates of the oscilloscope and measure the resultant deflection 
recorded by the camera. This was done by changing the voltage level on the 
vertical plates when the trace was part way across the tube (in the case of 
the still-—film camera) which resulted in a step. The use of Q-stcp net- 
wor allowed an estimate of both the high— and low-frequency response of 
7 SU PRUE EEEEEEEEEEEEEEEEREEEEEEEEEEEiEEeE 
—See Sec. 7(cv)e 
