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ISB Adaptor RA-98

Country:  Great Britain (UK)
Manufacturer / Brand:  Racal Engineering (Racal Instruments) Ltd., Bracknell
Year: 1960 ?? Category: Miscellaneous (Other, Various) - see notes
Valves / Tubes 16: 6AS6 12AU7 6AU6 EB91 12AX7 6BA6 6BA6 6BA6 12AT7 6AU6 EB91 6AU6 6AS6 12AT7 6AS6 EF91 EF91
Main principle ZF/IF 100/18 kHz
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 100-125 / 200-250 Volt
Loudspeaker - - No sound reproduction output.
Power out
from Model: ISB Adaptor RA-98 - Racal Engineering Racal
Material Metal case
Shape Rack
Dimensions (WHD) 483 x 133 x 355 mm / 19 x 5.2 x 14 inch
Notes Independent Side Band Adaptor matching the RA-17 family receivers, allows reception of USB, LSB and ISB signals.
This adaptor is equipped with a motor driven AFC system locking on pilot carrier for ISB / ECSS reception. The AFC must kept switched off for SSB signals without any carrier.
The 100 kHz 3rd IF of the RA-17 is mixed with an LC (only in variant RA-98D crystal controlled) 118 kHz oscillator signal for a new IF of 18 kHz. By mixing with another 18 kHz oscillator signal, the audio information of both sidebands is extracted.
Variants: RA-98A / B similar with different connectors, RA-98C with extended low frequency audio response to 150 Hz for receiving commercial broadcast transmissions (ISB feeders), RA-98D with internal crystal controlled 118 kHz oscillator for reception of SSB signals without carrier, RA-98E with an additional transistorized coupling circuit for use with transistorized receivers (as RA-1217).
Net weight (2.2 lb = 1 kg) 17.3 kg / 38 lb 1.7 oz (38.106 lb)
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.


Forum contributions about this model
Racal Engineering: ISB Adaptor RA-98
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racal: RA-98 (RA98) ISB Adaptor: variants
Martin Bösch
  1 Variants of the RA-98 SSB Adaptor:
RA-98A: British type coaxial connectors, no internal crystal controlled 188 kHz oscillator,
       need external 118 kHz source for hich stability ECSS operation.
RA-98B: US typ coaxial connectors and Monitor jack socket, no internal crystal controlled 188 kHz         oscillator
RA-98C: broadcast version of R-98B
RA-98D: with internyl crystal controlled 118 kHc oscillator with crystal oven
       switched by AGC - control knob.
RA-98E: with transistorized coupling circuit for use with transistorized receivers as RA-217 and             RA-1217
RA-98F: RA-98A modified for use with RA-317.
Racal Engineering: ISB Adaptor RA-98
End of forum contributions about this model