30
Interference Rejection
FT-891 Advance Manual
WIDTH (IF DSP Bandwidth) Tuning (SSB/CW/RTTY/DATA Modes)
The IF WIDTH tuning system allows the width of the DSP IF passband to be varied, this
may reduce or eliminate interference.
Moreover, the bandwidth may actually be
expanded
from the default setting, this may
enhance incoming signal fidelity when interference on the band is low.
1. Press the [
F
] key repeatedly, to find the
“FUNCTION-1” list screen.
2. Rotate the
MULTI
function knob to select
“WDH”.
3. Press the
MULTI
function knob, and then
rotate it counter-clockwise to narrow the
bandwidth and reduce interference.
r
To increase the bandwidth, rotate the
knob clockwise.
4. When the adjustment is completed, press
the
MULTI
function knob.
5. Press and hold the [
F
] key for one second
to exit the “FUNCTION-1” list screen and re-
sume normal operation.
r
To set the IF WIDTH Operation to “OFF”:
1. Press the [
F
] key repeatedly, to find the “FUNCTION-1” list screen.
2. Rotate the
MULTI
function knob to select “WDH”, and then press the
MULTI
function
knob.
3. Press and hold the [
F
] key for one second to exit the “FUNCTION-1” list screen
and resume normal operation.
r
WIDTH function may be assigned to the [A], [B] or [C] key. Refer to “Changing the
function assigned to the [A]/[B]/[C] keys” in the FT-891 Operating Manual.
Referring to Figure (B), the default bandwidth
of the SSB mode is illustrated.
By rotating the
MULTI
function knob to the
left, the bandwidth will narrow (see Figure
(A)), while rotation of the
MULTI
function
knob to the right, will increase the bandwidth
as depicted in Figure (C).
The default bandwidths, and total bandwidth
adjustment range, will vary according to the
operating mode:
(A)
(B)
(C)
IF BANDWIDTH IF BANDWIDTH IF BANDWIDTH
MULTI
MULTI
MULTI
SSB Mode: 1.8 kHz - 3.2 kHz (default: 2.4 kHz).
CW Mode: 500 Hz - 3 kHz (default: 2.4 kHz)
RTTY/DATA (LSB, USB) Modes: 500 Hz - 3 kHz (default: 500 Hz)
AM Mode: Fixed at 9 kHz
FM/DATA-FM Modes: Fixed at 16 kHz
