D Apf (Audio Peak Filter) Operation; D About 137 Khz Band Operation (Europe, Uk, Italy, Spain, France Versions Only) - Icom IC-7800 Instruction Manual

4
RECEIVE AND TRANSMIT
D D APF (Audio Peak Filter) operation
D D About 137 kHz band operation (Europe, UK, Italy, Spain, France versions only)
• Connection diagram for 137 kHz band operation
[APF/TPF] [APF/TPF]
(MAIN) (SUB)
[DIGI-SEL] [DIGI-SEL]
(MAIN) (SUB)
to [ACC2] pin 6*
to [RELAY] (for transmit/receive control)
*Transverter ON/OFF control signal related to the power amplifier
unit main power, if desired.
• ON: 2–13.8 V DC input (more than 10 kΩ impedance)
• OFF: Less than 2 V DC
The APF changes the audio frequency response by
boosting a particular frequency to enhance a desired
CW signal.
The peak frequency can be adjusted with [DIGI-SEL]
control when "APF" is selected for "DIGI-SEL VR Op-
eration" in miscellaneous (others) set mode (p. 12-18).
q During CW mode, push [APF/TPF] to turn the audio
peak filter ON and OFF.
• " " appears in the display and [APF/TPF] indicator
APF
above this switch lights green.
w Push [APF/TPF] for 1 sec. several times to select
the desired audio filter width.
• 320, 160 and 80 Hz filters are available.
e If "APF" is selected for "DIGI-SEL VR Operation,"
rotate [DIGI-SEL] control to suit your preference.
137 kHz band, within the 135.7 kHz to 137.8 kHz
range, operation in CW mode is optionally available
with the IC-7800.
The RF signal from [X-VERTER] is used for the
137 kHz band operation, and an external amplifier unit
is necessary.
See the connection diagram below for reference.
Power amplifier with T/R switching unit
for 137 kHz
to [X-VERTER]
4-6
BPF
PA
or
LPF