How To Tune; Tuning Knob - Icom IC-701 Instruction Manual

5-1 HOW TO TUNE
The following instructions are for tuning in any mode.
Please read carefully and understand fully before turning
on your unit. Proper tuning is necessary for optimum
operation.
5-1-1 TUNING KNOB
The transmit or receive frequency is displayed on 7 segment
LEDs down to 100Hz digits. Rotating the tuning knob
clockwise increases the frequency, while turning counter-
clockwise decreases the frequency in 100Hz steps. The
smaller vernier marks on the knob represent 100Hz and the
larger marks represent 1KHz. One complete rotation of
the tuning knob results in a 5KHz frequency increase or
decrease. When you receive your set, calibration of the
tuning knob may be desirable, as the large increments may
not correspond exactly to a change of 1KHz displayed on
the LEDs. Exact calibration is not necessary as the
displayed LED frequency will always be correct, but you
may calibrate the scale on the tuning knob for use as an
analog type frequency display. To calibrate, set a large
increment on the tuning scale to line up with the indicator
arrow directly above the scale and then turn ON the power.
To calibrate the scale during operation, if desired, set a
large increment on the tuning scale to line up with the
indicator arrow and then push the tuning speed button
TWICE. By doing so, the 1KHz and 100Hz digits are
cleared on the display to show "0.0".
The tuning knob scale may require recalibration if you:
1. Turn the knob while the frequency is locked by use
of the Dial Lock Button.
2. Use the tuning speed button when a large increment is
not lined up with the indicator.
3. Turn the knob beyond the band edge.
If the knob is too loose or too stiff for comforatble use,
you can adjust the torque by tightening or loosening the
brake adjustment screw accessable from underneath the set.
Brake adjustment screw
Brake Adjustment
The following instructions should be used to adjust the
tension of the Tuning Knob.
1. Remove the bottom cover of the IC-701.
2. The Tuning knob tension will become tighter by turning
the brake adjustment screw clockwise, and will become
looser by turning the screw counterclockwise.
3. While performing this adjustment, the Tuning knob must
be turned continuously as the screw is adjusted in order
to set the tension for a comfortable touch.
4. After the adjustment has been made, replace the bottom
cover.
On all but the 28MHz band, the displayed frequency will
not go beyond the highest band edge even by turning the
tuning knob clockwise, or beyond the lowest band edge by
turning the knob counter-clockwise. On the 28MHz band,
since this band width is much wider than the others, the
IC-701 provides "'automatic revert'' for operating con-
venience. When the frequency display shows 29.999.9MHz
and the tuning knob is turned clockwise, the displayed
frequency jumps down to 28.000.0MHz and continues up
from there. Likewise, by continuing to turn counter-clock-
wise beyond the bottom edge of the band, the frequency
jumps up from 28.000.0MHz to 29.999.9MHz and goes
down from that point.
The displayed frequency shows the carrier frequency in the
USB, LSB and CW modes, and the SPACE frequency in the
RTTY mode. Therefore recalibration of the frequency is
unnecessary when the mode is changed.
5-1-2 DIAL LOCK BUTTON
After the IC-701 is set at a certain frequency for rag chew-
ing, mobile operation, etc., pushing the Dial Lock button
will illuminate the Dial Lock LED and the VFO is locked at
the displayed frequency, thus inactivating the operation of
the tuning knob. To change the frequency, the Dial Lock
must first be disengaged by pushing the dial lock button
again. The Dial Lock display LED will go OFF, and the
frequency will change with the direction of the tuning Knob
rotation. Turning OFF the power will release the Dial Lock
and clear the displayed frequency.
5-1-3 TUNING SPEED BUTTON
Pushing the Tuning Speed Button will illuminate the dial
fast LED and the small vernier marks on the Tuning Knob
is changed to correspond to 10KHz steps. At the same time,
the 1KHz and 100Hz digits are cleared on the display to
show '0.0'... When the Tuning Speed Button is depressed
again, the dial fast display LED goes OFF and the small
vernier marks will again correspond to 100Hz steps. This
button will allow you to quickly OSY over a great
frequency range.
5-1-4 VFO SELECT SWITCH
The LSI in the IC-701 contains two ''VFO's" for both
receiving and transmitting. The VFO's are labeled "A".
VFO and "'B" VFO and are selectable with the VFO Select
Switch. This dual VFO system gives the IC-701 many very
convenient features. Please read this section very carefully
and perform the operation several times until you are
comfortable with the system.
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