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3)
Tune
in
an
RTTY
signal
using the
tuning
indicator of the terminal
unit or the
cross pattern
of
an
oscilloscope to center
the
receiver
on
the
signal.
Mark
frequency
is
2125Hz
and
space frequency
is
2295Hz.
Adjust the
PBT
CONTROL
as
required
for
the
best reception.
4)
If
an
optional
narrow
CW
filter
is
installed,
push
the
FUNCTION
SWITCH,
then the
RTTY
SWITCH
to
select
the
narrow
filter.
The
receiver selectivity
will
be narrowed.
•
OPTIONAL
FILTERS
FILTER
CENTER
FREQUENCY
CHARACTERISTICS
(BANDWIDTH)
-6dB
-60dB
FL-52A
455kHz
500Hz
1.0kHz
FL-53A
455kHz
250Hz
480Hz
5)
To
tune
RTTY
signals
with
a
wider
shift,
such
as
425Hz
or
850Hz,
obtain
a
demodulator
suitable for
the
desired
shift
and
use the
normal
RTTY
mode.
(3)
RTTY TRANSMITTING
1)
To
key
the
FSK
circuit, insert a
high
speed
relay
coil
into
the
loop current
circuit
of the
teletypewriter,
and connect
the
relay
contacts to
pins
8 and 9
of the
ACC SOCKET
on
the
rear panel.
2)
The
relay
contacts
make
during the
SPACE
and
break during the
MARK.
3)
Fine
adjustment
of the
MARK
and
SPACE
frequencies can be
made
by
adjusting the
trimmer
capacitors
in
the
MAIN
unit.
Refer
to
SECTION 13-4
ADJUSTMENT
LOCATIONS.
•
USING
A
LEVEL
CONVERTER
1)
When
a
level
converter
for
TTL
levels
is
used,
connect
th6
output
of
the converter to
pin
8
(ground)
and
pin
9 on
the
ACC
SOCKET.
2)
Apply
HIGH
level
(5V)
signals
for
MARK,
and
LOW
level
(OV)
for
SPACE.
If
your equipment
supplies reverse polarity
signals
(i.e.,
MARK:
OV,
SPACE:
5V),
slide
S2 on
the
MAIN
unit to the
REVERSE
position.
See
SECTION
13-4
ADJUSTMENT
LOCATIONS
for
the
S2
location.
•
USING
AN
AFSK
GENERATOR
1)
When
using
an
AFSK
generator
with
a
2125Hz
MARK
frequency
and
2295Hz
SPACE
frequency,
connect
the
output
signals
from
the
AFSK
generator to the
MIC
CONNECTOR
on
the front
panel or
ACC
socket
on
the
rear
panel.
2)
Push
the
LSB SWITCH.
6-8
GENERAL COVERAGE
RECEIVER
3)
VOX
T/R
switching
may
be used while operating
AFSK
for easier
operation.
NOTE:
-When
in
the
GENERAL COVERAGE
mode,
it
is
not
possible to
transmit
on any
frequency,
including the
Amateur
band
frequencies.
-
30
-
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