Table of Contents
Advertisement
OCUBIC
COMMUNICATIONS
SI/IIAIfI
DIVISION
AF GAIN control ' should vary the audio output from inaudible to
3.SV
RMS
before clipping occurs, with 0.5 uV of input signal.
Turning the IF GAIN control fully counterclockwise
should increase the
S meter reading to full scale
and decrease the
units sensitivity.
Set the
IF GAIN contra1 back to its fully clockwise setting.
Turning the
RF GAIN control counterclockwise should decrease the units
input sensitivity and the S meter reading should decrease.
With the RF GAIN
fully counterclockwise, input sensitivity should be reduced approximately 50
dB.
Set the RF GAIN control back to its fully clockwise position.
With the AGC DECAY control fully counterclockwise, the unit should have
no AGC delay time.
This is indicated by the S meter reading increasing and
decreasing instantly as the PTO
is tuned across a signal.
As the AGC DECAY
control is advanced clockwise,
the amount of time
required for
the AGC to
decay should increase
to approximately 15 seconds at fully
clockwise. This
is indicated by the slow drop in S meter readings after tuning off of a sig-
nal.
Set the AGC DECAY control back to its fully counterclockwise position.
Adjust the RF generator
so that the speaker audio tone is 1650 Hz
±
20
Hz.
Adjust the
NOTCH FILTER
control for
minimum speaker audio. The audio
signal should decrease approximately 25 dB.
Adjust the RF generator so that
the speaker audio tone
is 2500 Hz
±
20 Hz.
Adjust the
NOTCH FILT control
for minimum speaker
audio.
The audio
signal should
decrease aoout 25 dB.
Repeat the foregoing at 400 Hz
±
10 Hz audio tone.
The audio signal
should
decrease by aoout
25 dB.
Set the
NOTCH FILT control back to its fully co-
unterclockwise position.
NorSE BLANKER OPERATION
To check the noise blanker circuit,
connect a pulse type of noise gen-
erator to the
antenna connector
along with the
signal generator using the
"T" connector.
If a
noise generator is not available,
see the "Servicing
Hints" sec'tion of this manual for the schematic diagram of a simple inexpen-
sive set that may be constructed and kept for future use.
Tune in a 0.5 uV signal fr om the generator; turn on the noise generator
and set the noise level
to S
3 to S8 with the NOISE BLANKER switch
off.
Turn the NOISE BLANKER switch on; the signal should now be audible aoove the
residual noise.
Check on all bands.
Tune the signal generator to another frequency at least 1 MHz away from
the set frequency and modulate the signal generator at 100% modulation.
In-
crease the generator output to about 100,000 uV and at this point the noise
level should come back up to S4 to S8;
switching the
NOISE BLANKER switch
from on to off should have no effect.
PASSl3AND TUNING OPERATION
With the
PASSBAND control set at
12 o'clock,
all eight PASSl3AND KHZ
lights should be on
in LSB,
USB,
and CW modes.
In CWN mode, only the
1.
5
and 1.8 lights
should be on.
In LSB, USB and CW mode, as the PASSBAND con-
trol is turned clockwise, the PASSl3AND KHZ lights should go off sequentially
proceeding from left to right.
At aoout the 4 o'clock position
of the con-
trol, alllights
should be out.
As the PASSBAND control is turned counter-
clockwise from the 12 o'clock position,
the
PASSBAND KHZ
lights should go
off sequentially proceeding from right to left.
At aoout the 8 o'clock pos-
8-6
Advertisement
Chapters
Table of Contents
Troubleshooting
