|SWL since 1980 - OM since 1990|
Racal RA 1792 technical specifications
|Frequency Range||150 kHz to 30 MHz|
|Modes of Reception||
USB/LSB (R3E, H3E, J3E, R2A, H2A, J2A)
ISB (B8E) optional
Auxiliary - provides demodulated signal centered on optional fixed BFO offset frequency
|Tuning||Continuously tunable synthesizer in 10 Hz steps over the entire frequency range. Frequency setting either by numerical keypad or by single tuning knob with continuously variable tuning rate from 1 kHz per turn to approximately 20 kHz per turn, depending on the speed of rotation.|
|Pre-programmed Channels||EAROM memory unit may be programmed with up to 100 channel frequencies and mode which may be recalled by keypad or tuning control.|
|Channel Scanning||Automatic scanning of up to ten channels in any decade of the 100 stored channels. Dwell time on each channel variable in ten steps from 0.1 to 10 seconds; pre-selected by numeric keypad.|
Dependent upon frequency standard used:
|Cross Modulation||With a wanted signal of 1 mV EMF in a 3 kHz bandwidth, an unwanted signal 30% modulated removed not less than 20 kHz, must be greater than 500 mV EMF to produce an output 20 dB below the output produced by the wanted signal.|
|Reciprocal Mixing||With wanted signal of less than 100µV EMF in a 3 kHz bandwidth, an unwanted signal more than 20 kHz removed is generally greater than 65 dB above the wanted signal level to give a noise level 20 dB below the output produced by the wanted signal.|
|Blocking||With a wanted signal of 1 mV EMF, an unwanted signal more than 20 kHz removed must be greater than 1 V EMF to reduce the output by 3 dB.|
Two 100 mV EMF signals within the IF passband will produce third order intermodulation products not greater than -50 dB relative to the level of either tone at the IF output.
Out of band:
With two 30 mV EMF signals, separated and removed from the wanted signal by not less than 25 kHz, the third order intermodulation products are not less than 90 dB below either of the interfering signals.
External (including image and IF rejection):
External signals, removed more than 20 kHz from the wanted frequency, must be greater than +80 dB relative to 1 µV EMF to produce an output equal to that produced by a 1 µV EMF signal at the wanted frequency.
The presence of an internally generated spurious response generally will not degrade the specified receiver sensitivity by more than 3 dB.
An increase in input level of 110 dB above 2 µV EMF will produce an output change of less than 2 dB.
Short, medium and long - preset to be automatically selected by mode switching, but can be set indipendently by pushin-bottons. AGC lines are available at rear of receiver to permit remote control.
|IF Gain Control||
Control range 110 dB:
Gain control may be switched either to manually set receiver gain or AGC threshold.
|Pre-set Operating Conditions||
Bandwidth, AGC time constant and BFO offset may be preset for each mode so that they are automatically recalled when the mode is selected.
'Auxiliary' mode may be set up for any mode, bandwidth, AGC constant and BFO offset. In the ISB mode, diferent AGC time constants may be stored for the two sidebands.
|1st LO Output||10 dBm ±3 dBm into 50 ohm load, on read panel.|
|IF Output||455 kHz, nominal 100 mV into 50 ohms.|
|Muting||60 dB minimum by grounding rear panel connection.|
|Metering||Front panel display switched to indicate RF level or AF level output to line|
All measured supply voltages to be within ±20%
Varactor line voltage: -
20 MHz Reference Loop: 6 to 11 V DC
BFO Synthesizer: 8 V ±0.5 V DC
LO Synthesizer: 3.5 to 15 V
AC: Selections for 110, 120, 220 oer 240 V operation; +10% -15%. 45 to 65 Hz
DC: Receiver may also be operated from an 18 to 32 V DC source when receiver is equipped with optional DC power supply.
|Power Consumption||Approximately 60 VA for AC operation; approximately 40 Watts for DC operation.|
Height - 133 mm (5.29 in)
Width - 483 mm (19 in.)
Depth - 458 mm (18 in.)
|Weight||14 kg (31 lbs.)|
Radio Emission Codes
Radio Emission Codes are specified using three symbols as shown below:
First symbol - Type of modulation of main carrier
Second symbol - Nature of modulating signal
Third symbol - Nature of transmitted signal
The principal symbols are listed below:
|First Symbol||Type of Modulation|
Double sideband, AM
Indipendent sideband, AM
Vestigial sideband, AM
Single sideband full carrier
Single sideband suppressed carrier
Pulses, amplitude modulated
Pulses, width or duration modulated
Pulses, phase or position modulated
Single side band reduced or variable carrier
|Second Symbol||Nature of Modulating Signal|
No modulation signal
On/Off modulation (keyed CW)
Modulation sub carrier (keyed MCW)
Analogue modulation (voice)
Two or more channels on one frequency offering keyed telegraphy
Two or more channels on one frequency offering telephony (voice)
|Third Symbol||Type of Information Being Transmitted|
Telegraphy for aural reception
Telegraphy for automatic reception