Kenwood TS-990S - Manual (Page 139)

6-1
6 REJECTING INTERFERENCE
Index Contents
ATTENUATOR (ATT)
An attenuator is a function that attenuates or reduces
the received signal level. When there is a strong signal
present near the target signal, attenuating the adjacent
signals can reduce or eliminate the interference.
The target signal will also be attenuated; however, this will
facilitate you distinguishing the weak signal.
This will help a very strong signal from being distorted.
The transceiver is equipped with three levels of
attenuation, -6 dB, -12 dB, and -18 dB.
F[ATT]
1 [ATT] (F) to select the attenuation level of the received
signal.
• The attenuation level appears on the key guide displayed
on the right side of the main screen.
• Each time you press [ATT] (F), the level cycles as follows:
OFF > -6 dB > -12 dB > -18 dB > +10 dB > OFF. Each time
you press and hold [ATT] (F), the attenuation level cycles
in the reversed sequence.
PRESELECTOR
Selecting the narrow bandwidth tunable filter attenuates
the interfering signal which has 2 to 3 MHz separation
from the target frequency, instead of the strong interfering
signal in the adjacent frequencies.
[F1] [F7]
[ESC] [MULTI/CH] F [P.SEL]
1 Select the main band.
2 Press [P.SEL] (F) to enable or disable the Preselector.
The default is "OFF".
In the key guide [P.SEL] (F), the status of attenuator is
indicated on the lower line.
While the Preselector is active, the status indicators below
show how the operating band is shifted from the center
frequency.
◀ON:
The filter bandwidth has been shifted to below the center
frequency.
On
The filter bandwidth has been positioned at the center
frequency.
ON▶:
The filter bandwidth has been shifted to above the center
frequency.
Note:
◆ The Preselector can only be used for the main band.
◆ Preselector can be used in the 1.8 MHz band, 3.5 MHz band, 7
MHz band, 10 MHz band, 14 MHz band, 18 MHz band, 24 MHz
band, and 28 MHz band.
◆ Preamplifier and Preselector cannot be enabled at the same time.
Enabling the Preselector while the Preamplifier is active temporarily
disables the Preamplifier. The Preamplifier will be enabled again
when the Preselector is disabled.