Noise Blanker; Ipo (Intercept Point Optimization); Att (Front End Attenuator); Dsp Bandpass Filter - Yaesu FT-897D Operating Manual

R A
ECEIVER
N
OISE
The IF Noise Blanker may be useful in reducing or elimi-
nating some types of impulse noise, especially noise gener-
ated by automotive ignition systems.
1. Press the [ F ] key momentarily, then rotate the MEM/
VFO CH knob, as needed, until Multi Function Row "l"
[ NB, AGC, OFF ] appears on the display.
2. Press the [ A ]( NB ) key to activate the Noise Blanker. Pa-
rentheses will appear on both sides of the "NB" selec-
tion, indicating that the Noise Blanker is now on.
3. To adjust the blanking level, press and hold in the
[ A ]( NB ) key for one second. This instantly activates
Menu Mode No-063 [ NB LEVEL ] , which allows adjust-
ment of Noise Blanking Level. Rotate the DIAL knob to
set a higher or lower blanking level (on a scale of 0 to
100). When done, press and hold in the [ F ] key for one
second to save the new setting and return to normal op-
eration.
4. Press the [ A ]( NB ) key again to turn the Noise Blanker
off.
IPO
( I
The IPO feature bypasses the receiver RF preamplifier,
thereby eliminating the preamp's gain. This feature is not
available on the 144 MHz and 430 MHz bands.
1. Press the [ F ] key momentarily, then rotate the MEM/
VFO CH knob, as needed, until Multi Function Row
"m" [ IPO, ATT, NAR ] appears on the display.
2. Press the [ A ]( IPO ) key to bypass the receiver input pream-
plifier. Parentheses will appear on both sides of the "IPO"
selection, and the " " icon will appear on the display.
indicating that the preamp is now disengaged from the
receiver circuit.
3. Press the [ A ]( IPO ) key once more to re-activate the
preamp.
On the bands below 14 MHz, the input pream-
plifier is rarely necessary, and activation of the
IPO feature will provide substantial protection
against intermodulation and other problems associated
with strong signal input to the receiver. Rule of thumb: so
long as the S-meter is moving on background noise, addi-
tional front-end gain is not necessary.
Page 26
CCESSORIES
B
LANKER
)
P O
ATT
( F
The Attenuator will reduce all signals (and noise) by 10 dB,
and it may be used to make reception more pleasant under
extremely noisy conditions. This feature is not available on
the 144 MHz and 430 MHz bands.
1. Press the [ F ] key momentarily, then rotate the MEM/
VFO CH knob, as needed, until Multi Function Row
"m" [ IPO, ATT, NAR ] appears on the display.
2. Press the [ B ]( ATT ) key to activate the Attenuator. Pa-
rentheses will appear on both sides of the "ATT" selec-
tion, and the " " icon will appear on the display.
3. Press the [ B ]( ATT ) key once more to switch the Attenu-
ator out of the receiver front end circuit. Signals will
again be received at a level 10 dB louder than was the
case when the Attenuator was engaged.
DSP B
ANDPASS
In the SSB mode, the receiver's selectivity may be enhanced
via the DSP Bandpass Filter.
1. Press the [ DSP ] key momentarily. This instantly acti-
vates Multi Function Row "p" [ DNR, DNF, DBF ] .
2. Press the [ C ]( DBF ) key to activate the DSP Bandpass
Filter. Parentheses will appear on both sides of the "DBF"
selection, and the "DSP" will appear at the center top
on the display. You will notice a decrease in both back-
ground noise and interference, if any is present.
3. The bandwidth of the DSP filter may be modified, to
customize the bandwidth to your operating needs. To
adjust the Low-Cut and High-Cut characteristics of the

DSP Bandpass Filter:

• Press and hold in the [ C ]( DBF ) key for one second.
This instantly activates Menu Mode No-047 [ DSP
LPF CUTOFF ] , which allows adjustment of the High-
Cut (Low-Pass) filter.
• Turn the DIAL, as desired, to adjust the high-fre-
quency cutoff of the DSP Bandpass Filter.
• Now rotate the MEM/VFO CH knob one click
counter-clockwise to select Menu Mode No-047
[ DSP HPF CUTOFF ] , which allows adjustment of the
Low-Cut (High-Pass) filter.
• Turn the DIAL, as desired, to adjust the low-frequency
cutoff of the DSP Bandpass Filter.
• When done, press and hold the [ F ] key for one sec-
ond to save the new setting(s) and return to normal
operation.
4. Press the [ C ]( DBF ) key once more to disable the DSP
Bandpass Filter.
HPF
100 Hz~1000 Hz
FT-897D O
)
E A
F
ILTER
LPF
1000 Hz~6000 Hz
M