Receive And Transmit; Mode Selection; Twin Pbt Operation; Rtty - Icom IC-756 Instruction Manual

4

RECEIVE AND TRANSMIT

Mode selection

The following modes are available in the IC-756:
SSB (LSB/USB), CW, CW-R (CW reverse), RTTY,
RTTY-R (RTTY reverse), AM, FM and FM-T (FM with
subaudible tone). Narrow modes of each of these are
also available.
To select a mode of operation, push the desired mode
switch momentarily. Push the switch again to toggle
between normal and narrow mode. Push the switch
for 2 sec. to toggle between USB and LSB, CW and
CW-R, RTTY and RTTY-R, FM and FM-T, if neces-
sary.
See the diagram at right for the order of selection.

Twin PBT operation

The twin PBT (Passband Tuning) function electronically
narrows the receiver's IF passband widths to reduce
interference. Moving both [TWIN PBT] controls to the
same position shifts the IF.
- The LCD shows the passband width graphically.
Variable range depends on the filter selection. ± 1.29
kHz in 15 Hz steps and ± 258 kHz in 3 Hz steps are
available.
PBT OPERATION EXAMPLE
Both controls at
center position
TWIN PBT
IF center frequency
25
USB
CW

RTTY

FM
Push mode switch
for 2 sec.
• [TWIN PBT] should normally be set to the center
positions when there is no interference.
• When PBT is used, the audio tone may be
changed.
• PBT may not function with some IF filter combina-
tions.
• Not available for FM mode.
Cutting a lower
passband
TWIN PBT
Passband
Interference Desired signal
SSB
LSB USB-N
CW
CW-R CW-N
RTTY
RTTY-R RTTY-N
AM
AM
FM
FM-T FM-N
Cutting both higher and
lower passbands
TWIN PBT
Interference
Desired signal
LSB-N
CW-RN
RTTY-RN
AM-N
FM-TN
Push mode switch
momentarily.
Passband
Interference