Operation
12
PRELIMINARY SETTING-UP.
4. The instructions given below are concerned with tuning the receiver to a signal of
known frequency. These instructions (1) to (8) apply with the V.F.O. switch in either
position.
(1) Set the power switch to ON. Allow a few minutes for the receiver to warm-up.
(2) Set the R.F. RANGE MC/S switch to WIDEBAND.
(3) Set R.F. ATTENUATOR to MIN.
(4) Set A.F. GAIN control to its mid-position.
(5) Set SYSTEM switch to MAN.
(6) Set LIMITER and B.F.O. switch to OFF.
(7) Select bandwidth of 3 or 6.5 kc/s.
(8) Rotate the R.F./I.F. GAIN control to three-quarters of fully clockwise.
FILM SCALE CALIBRATION
5.
(1) Set the SYSTEM switch to CAL.
(2) Select BANDWIDTH of 3 kc/s.
(3) Set the KILOCYCLES scale to that of the 100 kc/s point which is nearest to
the frequency required and adjust the control accurately until a zero-beat note is
obtained. Move the milled cursor slide on the dial escutheon so that the pointer
coincides exactly with the selected 100 kc/s division.
(4) Restore all other controls to the preliminary setting shown in para.4. above.
B.F.O. CALIBRATION
6.
(1) Set the B.F.O. to on.
(2) Set the SYSTEM switch to CHECK B.F.O.
(3) Adjust the B.F.O. NOTE KC/S control to zero-beat.
(4) Restore all other controls to the preliminary setting shown in para.4. above.
TUNING
7.
(1) Set R.F. RANGE MC/S to the desired frequency band.
(2) Set R.F. ATTENUATOR to MIN.
(3) Set MEGACYCLES dial to the required integer (1 to 29). The position of maxi-
mum receiver noise will indicate the correct setting.
(4) Set SYSTEM switch to CAL.
(5) Set Bandwidth to 3 kc/s.
(6) Set A.F. GAIN to mid-position.
(7) Adjust KILOCYCLES scale to zero beat at the 100 kc/s point nearest to the
desired frequency.
(8) Adjust the milled cursor slide to coincide with this point.
(9) Switch B.F.O. on.
(10) Set SYSTEM switch to CHECK B.F.O.
(11) Adjust B.F.O. NOTE KC/S control to zero beat.
Summary of Contents for RA-117
Page 1: ...Racal RA 117 Radio Receiver...
Page 24: ...Detailed Circuit Description 24 at maximum is the correct calibration maintained...
Page 32: ...32...
Page 70: ...Illustrations 70...
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