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the setting of the RIT contro! knob.
When the RIT circuit is ON, if the tuning knob is moved by
one increment, the RIT circuit is automatically pulsed OFF.
However, this function
can be eliminated by changing the
connecting
pins in the driver
unit as shown
below, in
case you would
like the RIT to remain operational when
you turn the tuning knob.
Or, by continuously depressing
the RIT switch with your finger while turning the tuning
knob, the RIT circuit will remain operational while tuning.
Other things to remember
are:
The RIT circuit is ope-
rational
when the frequency
is locked with the dial lock
button.
The frequency shifted by turning the RIT control
is not
indicated
on
the frequency
display.
When
the
transmitting and receiving frequencies differ by more than
800Hz, use "A" and "'B'' VFQs as outlined previously.
»
5-2
SSB OPERATION
5-2-1
RECEIVING:
After connecting an antenna, microphone, etc., set knobs
and switches as follows.
POWER SWITCH
OFF
T/R SWITCH
RECEIVE (UP)
VOX SWITCH
OFF (UP)
ATT SWITCH
OFF (UP)
AGC SWITCH
SLOW (UP)
NOISE BLANKER
(NB) SWITCH
OFF (UP)
MODE SELECT SWITCH
USB or LSB
VFO SWITCH
BAND SELECT SWITCH
AF GAIN CONTROL
RF GAIN CONTROL
P.B. TUNE CONTROL
RIT CONTROL
"AO or "BY"
Desired Band
Completely Counter-clockwise
Completely Clockwise
Center (12 o'clock) position
Center (12 o'clock) position
The other knobs are unrelated to receiving and need not
be set at this time.
In SSB operation there is both an USB (upper side band)
and an LSB (lower side band).
LSB is usually used on the
1.8, 3.5 and 7MHz bands, while USB is usually used on the
14, 21 and 28MHz
bands.
Select the mode according to
the band in which you wish to operate.
Now turn ON the power switch.
The meter lamp will be
illuminated
and the lowest frequency of the selected band
will be shown on the LED readout.
Slowly turn the AF
gain contro! clockwise to a comfortable level.
Rotate the
tuning knob until a signal is received.
The multi-function
meter needle will move according to the signal strength, so
tune for the highest possible meter reading and the clearest
audio.
If you cannot get a clear signal, you may be receiv-
ing in the opposite sideband.
{f so, change the mode switch
to the proper sideband.
The VFOs in the IC-701 change in 100Hz steps. Therefore
the
maximum
possible
difference
in your
receiving fre-
quency and the received signal frequency is 50Hz.
However,
for normal voice signal reception, a difference of 50Hz is
negligible and indeed may be hard to distinguish.
Since the
frequency is changed
in 100Hz steps with the IC-701, as
opposed to continuous
variable frequency systems, tuning
is simplified and more accurate.
5-2-2
NB (NOISE
BLANKER)
Turn the noise blanker ON (down) when there is pulse type
noise,
such
as
ignition
noise
from
automobile
motors.
Noise
will
be suppressed
and even
weak signals will be
received comfortably.
The noise blanker may not work as
effectively when there is a strong signal on a nearby fre-
quency or when there is continuous (not pulse type) noise.
5-2-3
AGC
(AUTOMATIC
GAIN
CONTROL)
The IC-701 has a ''hang'' AGC system which holds the peak
voltage of rectified AF signals from the detector circuit for
a certain period.
Therefore, during the pauses in normal
speech of the received signal, uncomfortable noises will not
be heard.
The multi-function
meter
indicates the peak
value for a certain period, facilitating reading of the meter
"S" function.
For normal
SSB reception, set the AGC switch in the UP
(slow) position.
Set the AGC switch in the FAST (down)
position, when tuning or receiving signals with short interval
fading. When in the FAST position, the hang AGC circuit is
turned OFF
and the time constant is shortened.
Use the
FAST position for RTTY reception.
5-2-4
ATT (ATTENUATOR)
SWITCH
Turn
the ATT
switch
ON
(down)
when strong nearby
signals disturb signal reception
or make "S'' reading dif-
ficult.
In the ON
position a 10dB
attenuator
is inserted
into
the
receiving
antenna
circuit,
reducing
interfering
signals
and
giving
more
stable
reception.
In normal
operation the ATT switch is left in the OFF (up) position.
5-2-5
P.B. (PASS BAND) TUNING
Pass Band Tuning is a system in the receive mode to narrow
the band width (selectivity) of the frequencies that will pass
through the crystal filter electrically from either the upper
or flower side continuously by up to 1.5KHz.
This is very
secre
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