Icom IC-251A Instruction Manual page 22

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When you want to change to the SIMPLEX mode from DUPLEX operation, set the VFO/
MEMORY Switch to the A or B position. The transmit and receive frequency will now be cont-
rolled by ""A'' VFO or "'B" VFO, but the other VFO will not follow the selected VFO.
RIT (RECEIVE INCREMENTAL TUNING)
By using the RIT circuit, you can shift the receive frequency +800Hz either side of the transmit
frequency without moving the transmit frequency itself. Therefore, when you get a call slightly
off frequency, or when the other station's frequency has shifted, you can tune in the receiving
frequency without disturbing the transmitting frequency. By pushing the RIT switch down once
(it's a spring loaded switch) the RIT circuit is turned ON and the RIT LED is lit. The receive fre-
quency is shifted with the RIT knob.
When the RIT knob is in the "0" position, the transmitting and receiving frequencies are the same.
Rotating the control to the (+) side raises the receiving frequency, and rotating to the (—) side
lowers the frequency. To turn OFF the RIT control, again push the RIT switch once and the RIT
LED will go OFF. When the RIT circuit is OFF, the transmit and receive frequencies are the same
regardless of the setting of the RIT control 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 continuously depressing
the RIT switch with your finger, while turning the tuning knob, the RIT circuit will remain opera-
tional while tuning.
Other things to remember are: The RIT circuit is operational when the frequency is locked with
the dial lock switch. 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" VFOs as outlined previously.
MEMORY CHANNEL OPERATION
MEMORY-WRITE (PROGRAMMING THE MEMORY CHANNELS)
Only "A" VFO can be used for memory-writing.
1. Set the Tuning Control to the desired frequency, using '""A'' VFO. For example, set it for
145.700.0 on the display.
2. Set the VFO/MEMORY Switch to the channel to be programmed (1, !2], or (3]). For example,
set it at Memory Channel 1. If no frequency has been programmed since turning the power of
the unit ON, 145.000.0 will be shown on_the display and the unit will receive on this fre-
quency.
3. One push of the MS/MW Button erases the previous programmed frequency (145.000.0) and.
programs the new frequency (145.700.0) into Memory Channel 1.
4. Program any desired frequencies in Memory Channels [2] and [3] in the same manner. Memory
Channels [2] and [3] are used also for the Programmed Scan. For Programmed Scan operation,
refer to SCANNING OPERATION.
MEMORY READING
Set the VFO/MEMORY Switch to the desired Memory Channel 1, [2], or (3). At whichever fre-
quency the "'A" or "B" VFO was set, that previously programmed frequency is recalled. When the
VFO/MEMORY Switch is set back to."A" or "B" VFO, the previous operating frequency of that
VFO will again be shown on the display.