45

REJECTING INTERFERENCE

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■FM
In FM mode, you cannot change the reception IF filter
bandwidth. The bandwidth is fixed at 12 kHz.

IF SHIFT (SSB/ CW/ FSK)

Shifting the center frequency of the filter pass band is
an additional method of removing adjacent frequency
interference. Shifting this center frequency does not
change the current reception frequency.
To remove interference that is higher in frequency
than the desired signal, turn the IF SHIFT control
counterclockwise. To remove interference that is
lower in frequency than the desired signal, turn the IF
SHIFT control clockwise.
MULTI IF
SHIFT
Desired
signal Interfering
signal
IF pass band

IF FILTER

The IF filters are designed for selecting the exact
range of intermediate frequencies that are sent to the
next stage in the receive circuit. Interference
adjacent to the desired signal can be reduced by
selecting a narrow bandwidth filter and/ or shifting the
center frequency of the filter.
To more effectively remove interference, combine the
IF filtering and the DSP filtering (AF) described on
pages 46 and 47.

CHANGING THE IF FILTER BANDWIDTH

When adjacent frequency interference is present at
both sides of the desired signal, narrowing IF filter
bandwidth may be the best way to remove the
interference. Changing the filter bandwidth will not
effect the current reception frequency.
You can install 2 optional IF filters for SSB, CW, and
FSK modes. After installing the optional filters
{page 81}, the transceiver automatically recognizes
what type of optional filters are installed.
■SSB/ AM
When you operate the transceiver in SSB or AM
mode, you can manually select the wide or narrow
filter.
Press [FIL/ NAR] (1 s) to select another IF filter.
•Each press of [FIL/ NAR] (1 s) changes “ ”
(Normal) / “NAR”, then back to “ ” (Normal).
•If Menu No. 17 is ON (default is OFF) and 2 IF
filters have been installed, you can select
secondary IF filter. In this case, each press of
[FIL/ NAR] (1 s) changes “ ” (Normal) / “NAR”
/ “NAR 2”, then back to “ ” (Normal).
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Optional YF-107SN filter must be installed.
2
Optional YF-107C filter must be installed and Menu No. 17 must
be set to ON.
3
Optional YF-107CN filter must be installed and Menu No. 17
must be set to ON.
■CW/ FSK
When you operate in CW or FSK mode, the wide filter
or narrow filter is automatically selected according to
the DSP filter bandwidth that you select.
The following table describes how the optional filter is
selected as you change the bandwidth of DSP filter.
You cannot manually select the IF filter. To change
the DSP filter bandwidth, refer to “CHANGING THE
DSP FILTER BANDWIDTH” {page 46}.