Icom IC-551D Instruction Manual page 11

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VFO SWITCH
Selects an operating VFO from "A" VFO and "B" VFO, and selects the other various
operations.
О
Аэ В Instantly sets the frequency of "В" VFO to the same as that of "A" VFO.
MS Sets the MEMORY SCAN function. Push the MS/MW Button to start scanning the
three programmed frequencies in Memory Channels 1, [2] and [3].
A Selects "A" VFO for both transmit and receive. "А" Scan is started by pushing the
MS/MW Button while at this setting. |
B Selects "B" VFO for both transmit and receive. "В" Scan is started by pushing the
MS/MW Button while at this setting. —
RA-TB Selects "А" VFO for receive and "B" VFO for transmit.
RB-TA Selects "B" VFO for receive and "А" VFO for transmit.
1, [2], [3] Selects the three Memory Channels. [2] and [3] are. also used for Programmed Scan
operation. For details of this operation, refer to MEMORY CHANNEL OPE-
RATION on page 19.
In addition, when the VFO is switched from "A" VFO to "B" VFO, the frequency indicated
on the frequency display just prior to switching goes into a memory inside the CPU chip.
Thus, even if "B" VFO is being used, switching to "А" again will enable you to operate at the
initial frequency. Switching from "А" to "B" results in the same operation.
RIT CONTROL
Shifts the receiver frequency +800Hz either side of the transmit frequency. When the RIT is.
ON, the RIT LED is illuminated. The LED also represents the "0" position. Rotating the
control to the (+) side raises the receiver frequency, and rotating to the (—) side lowers the
receiver frequency. With the RIT ON, if the Tuning Control Knob @ is moved one increment,
the RIT circuit is automatically pulsed OFF. Therefore it is not necessary to manually turn `
OFF the RIT when changing operating frequency. The frequency shift by tuning the RIT
Control is not indicated on the frequency display.
RIT SWITCH . | |
This is a spring-loaded switch for the RIT Control. To turn ОМ the RIT, push down опсе. |
the OFF position is desired, push down again. When the RIT is ON, the LED above the RIT
control knob is lit. This LED also indicates the center position of the RIT control. When the
RIT circuit is OFF, the LED is also OFF.. Also, if the RIT is ON, rotating the Tuning Knob
by one increment will pulse the RIT OFF. The remains ON even after the power is
turned OFF.
NOISE BLANKER SWITCH
When pulse-type noise such as automobile ignition noise is present, set this switch to the ON
(down) position. The noise will be reduced орош comfortable reception.
AGC (AUTOMATIC GAIN CONTROL) SWITCH
With this switch you can select the time constant of the AGC circuit. With the switch in the
AGC (up) position, the AGC voltage is released slowly, and thus is suitable for SSB reception.
With the switch in the FAST (down) position, the AGC voltage is released faster, and the AGC
is suitable for stations suffering from fast fading or when operating in the CW mode.