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ISB Adaptor RA-121B US version

Country:  Great Britain (UK)
Manufacturer / Brand:  Racal Engineering (Racal Instruments) Ltd., Bracknell
Year: 1965 ?? Category: Miscellaneous (Other, Various) - see notes
Valves / Tubes 12: 6AS6 6AU6 6U8 12AX7 12AT7 12AT7 6AS6 6AS6 6X4 EF91 EF91 DG7-32
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 100-125 Volt
Loudspeaker - - No sound reproduction output.
Power out
from Model: ISB Adaptor RA-121B [US version] - Racal Engineering Racal
Material Metal case
Shape Rack
Dimensions (WHD) 19 x 5.25 x 0 inch / 483 x 133 x 0 mm
Notes US variant of Independent Side Band Adaptor RA-121 matching the RA-17 family receivers, allows reception of USB, LSB and ISB signals.
The 100 kHz 3rd IF of the RA-17 is mixed with a 118 kHz oscillator signal for a new IF of 18 kHz. 18 kHz +/- 6 kHz bandpass filters separate the audio signal of the two sidebands, which are fed to separate audio frequency amplifiers.
A switch allows correct setting of USB / LSB for RA-17 and RA-117 receivers.
A CRT tube which produces a Lissajou figure is used for indication of correct tuning of receiver and adaptor tuning.
Variants: RA-121A with European tubes and connectors, RA-121D with more stable crystal controlled 118 kHz oscillator.
Mentioned in Racal Handbook, Rinus Jansen

Model page created by Martin Bösch. See "Data change" for further contributors.

All listed radios etc. from Racal Engineering (Racal Instruments) Ltd., Bracknell
Here you find 105 models, 50 with images and 11 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.