Noise Blanker; If Filter (Bandwidth) Selection - Yaesu Mark-V FT-1000MP Operating Manual

O
PERATION
N B
OISE LANKER
Press the [ NB ] button to activate the IF Noise
Blanker.
The two noise blanker circuits in the MARK-
V FT-1000MP are provided for two different types of
pulse noise; (A) a narrow-pulse blanker for short pulse
noise such as from switching transients, automobile
ignitions, and power lines, and (B) a wide pulse blanker
for longer duration man-made pulse noise. This noise
blanker can sometimes also reduce the level of static
crashes from electrical storms You can select the de-
sired noise blanker circuit ("narrow" or "wide") and its
blanking level via menu selection 2-8.
In urban environments, there may be several or
even dozens of local noise sources; these may com-
bine in such a way as to make detection of a clear
"impulse" impossible. The IF noise blanker may, how-
ever, reduce the noise level significantly, allowing the
EDSP Noise Reduction feature to reduce the noise
even further.
If the blanker seems to distort a signal you're lis-
tening to, reduce the setting for optimum readability, or
turn it off. During periods of extreme signal density
(such as a contest), the noise blanker is best left off.
( B
IF F
ILTER ANDWIDTH
There are two banks of select-
able filters, one each for both the
8.215 MHz 2nd IF and 455 kHz
3rd IF in the Main Receiver. Filter
selections can be cascaded for versatility in combat-
ting QRM and tailoring received audio. From the fac-
tory, 2nd IF 500 Hz and 2.4 kHz filters and 3rd IF 2.4
kHz filter are provided. Other filters can be ordered
from your Yaesu dealer. Installation instructions are cov-
ered on page 113 and filter menu selections (5-0 through
5-7) on pages 101 and 102. The illustration at the bot-
tom of the page provides a representation of filter se-
lection in the MARK-V FT-1000MP.
Main receiver (VFO-A) IF Bandwidth Filter Selection
2nd IF
MODE
( 8.2MHz )
SSB 2.4 kHz/ATT
CW 2.0/2.4 kHz
AM
RTTY/PKT/USER 2.4 kHz
ø 1: You can select the bandwidth via menu selections 5-0 . The forward value (bandwidth) is factory default.
ø 2: You can select the bandwidth via menu selections 5-2 . The forward value (bandwidth) is factory default.
ø 3: You can select the bandwidth via menu selections 5-4 . The forward value (bandwidth) is factory default.
page 46
D
EALING WITH
) S
ELECTION
NOR
3rd IF
( 455 kHz )
ø 1 ø 1
2.4/6.0 kHz
ø 2 ø 2
2.0/2.4 kHz
ATT 6.0 kHz
2.4 kHz
I
NTERFERENCE
Select the desired bandwidth by pressing one of
the [ BANDWIDTH ] buttons. The LEDs inside each but-
ton glow red while selected.
In the AM mode, the [NOR] (6-kHz) AM-wide band-
width is typically selected for both the 2nd & 3rd IF
(labeled THRU on the bottom of the 2nd IF column).
This gives the highest fidelity, and is best on strong AM
signals (and particularly music). The effects of the
SHIFT and WIDTH controls in this wide bandwidth are
subtle, but they can be helpful in fine tuning the audio
characteristics. For weaker AM signals, or where adja-
cent channel interference is present, the [NAR 1] (2.4
kHz bandwidth) offers a compromise between inter-
ference rejection and fidelity. In this case, the SHIFT
and WIDTH controls can be used quite effectively to
improve fidelity (see the illustrations).
However, even better reception of AM signals un-
der difficult conditions can usually be had by switching
to an SSB mode (whichever gives the clearest recep-
tion), and superb reception of weak signals is often
possible using diversity reception, described on page
46.
In SSB modes, the [ NAR 2 ] (2.0 kHz bandwidth)
button can sharply cut interference from unwanted sig-
nals on either side of the desired signal (although with
some necessary loss of fidelity). In CW, the [ NOR ] (2.0
kHz or 2.4 kHz bandwidth) is often convenient to give
"a wide view" of the band when tuning around, but once
a signal of interest has been found and centered in the
passband, the [ NAR 1 ] (500 Hz bandwidth) or [ NAR 2 ]
(250 Hz bandwidth) selections are much better.
In addition to selecting various filter combinations,
you have several features that can be used singly, or
in combination to eliminate or reduce the interference
to an acceptable level. Although their use requires little
more than rotating a control, it is good to have knowl-
edge on how each function works and the effect on the
QRM encountered.
NAR 1
2nd IF 3rd IF
( 8.2MHz ) ( 455 kHz )
2.0 ( 2.4 ) kHz 2.0 ( 2.4 ) kHz
500 Hz 500 Hz
2.4 kHz 2.4 kHz
2.0 kHz 2.0 kHz
MARK-V FT-1000MP Operating Manual
NAR 2
2nd IF 3rd IF
( 8.2MHz ) ( 455 kHz )
N/A ( 2.0 kHz ) N/A ( 2.0 kHz )
250 Hz 250 Hz
2.0 kHz 2.0 kHz
ø 3
250/500 Hz 250/500 Hz
ø 3