Page 62 FTDX5000 OPERATING MANUAL
I
NTERFERENCE
R
EJECTION
(
S
IGNALS
WITHIN
3
KHZ
)
USING IF SHIFT AND WIDTH TOGETHER
(
SSB/CW/RTTY/PKT/AM MODES
)
The IF Shift and Variable IF Width features, together, form a very effective interference-fighting filter system.
IF
BANDWIDTH
IF
BANDWIDTH
IF
BANDWIDTH
Desired Signal Desired Signal Desired Signal
QRM
QRMQRMQRM
QRMQRM
For example, in Figure “A” you can see how interference
has appeared both on the high and low sides of the desired
signal. By pressing the
[
WIDTH
]
button (the button will
glow red) and then rotating the
[
SELECT
](
width
)
knob,
as shown in Figure “B”, the interference from one side
can be eliminated, then press the
[
SHIFT
]
button to change
the function of the
[
SELECT
]
knob to the SHIFT knob
(the
[
SHIFT
]
button glows red. However, the IF Width
adjustment is not changed). Now, by re-positioning the
[
SELECT
](
shift
)
knob (Figure “C”), the interference on
the opposite side can be removed, without re-introducing
the interference previously eliminated in Figure “B”.
ADVICE:
The Width and Shift features are the primary tools you
should use for best interference reduction. After narrow-
ing the bandwidth (width) and/or adjusting the center of
the passband (shift), the Contour control may also yield
further signal-enhancement benefits on the net residual
bandwidth. Additionally, the IF Notch Filter (see the next
section) may be utilized, in conjunction with the three other
filter systems, to significant advantage.
ABC
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