Introduction - Racal Instruments RA-117 User Manual

4. Introduction

General Description
1. The Communications Receiver Type RA.117 has been designed for use as a general
purpose receiver which will provide a high order of selectivity and stability. The re-
ceiver covers a frequency range from 1.0 to 30.0 Mc/s.
2. A built-in crystal-controlled calibrator provides reference signals at each 100 kc/s
division to permit exact alignment of the scale pointer. Two independent I.F. outputs,
in parallel, at 100 kc/s are provided for external use if required. A number of audio
outputs are available providing flexibility during operation; a small loudspeaker is
fitted for monitoring purposes.
3. The receiver is designed to operate from 100-125 volts and 200-250 volts, 45-65 c/s
main supply. The power consumtion is approximately 100 watts.
Constructional Details
4. The receiver is designed for both bench (table) and rack mounting. The front panel is
painted Light Battleship Grey (British Standard Specification 381C, colour 697) and
has been carefully designed to minimize operator fatigue.
5. The dimensions of the 1/8 in. thick front panel conform with the requirements for
mounting in a standard 19 in. rack.
6. For bench mounting, the receiver is fitted in a robust steel cabinet which has a rear
opening to enable the operator to gain easy access to the fuses and the termination
strips.
7. A dust cover is provided with both models. This may be removed from cabinet-
mounted receivers in conditions of high ambient temperature.
8. The chassis and major modules are of cast construction thus ensuring maximum rigid-
ity and effective electrical screening. Each receiver is supplied with three keys to facil-
itate removal of the control knobs, insulated trimming tool and coaxial terminations
for aerial and I.F. connections. Extra sleeves can be provided with the terminations
for alternative coaxial cable sizes.
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