Page 72
FT-450 O
PERATION
M
ANUAL
RTTY (R
ADIO
T
ELETYPE
) O
PERATION
Most RTTY operation today is accomplished using a TNC or other computer-based system that utilizes AFSK
tones. For RTTY operation using a Terminal Unit (TU) or the “FSK” output from a TNC, please see the discus-
sion below. See also the illustration for details regarding connection to your TU.
S
ETTING
U
P
FOR
RTTY O
PERATION
Before commencing RTTY operation, please direct
your attention to the setup steps shown in the chart
to the right.
B
ASIC
S
ETUP
1. Press the [
MODE
]/[
MODE
] buttons several
times to indicate both the “
” and “
” icons
on the display. Engage the RTTY operation us-
ing “LSB” injection, which is generally used in the
Amateur service.
2. When you begin typing on your TU or computer
keyboard, the command to transmit should auto-
matically be sent to the transceiver, causing it to
enter the transmit mode.
N
OTE
:
If you anticipate making data transmissions of longer
than a few minutes, we recommend that you reduce
the transmitter power to 1/2 ~ 1/3 of its normal maxi-
mum via Menu Item “
RFPOWER
”.
Q
UICK
P
OINT
:
In the
FT-450
, “RTTY” is a mode defined as being an
“FSK” mode, whereby the closing and opening of a
keying line (to ground) causes the Mark/Space tones
to alternate. The RTTY mode is not an AFSK based
mode in this transceiver, and the AFSK output tones
from a TNC will not cause Mark/Space shifting to oc-
cur. Use the “Packet” mode for AFSK-based Baudot
and other data modes.
M
ENU
I
TEM
RTY SFT (RTTY SHIFT)
RTY TON (RTTY TONE)
RTYRPOL (RTTY RX POLARITY)
RTYTPOL (RTTY TX POLARITY)
A
VAILABLE
V
ALUES
170 / 200 / 425 / 850 Hz
1275 / 2125 Hz
NOR / REV
NOR / REV
A
DVICE
:
There is no adjustment of the FSK input level
(FSK IN of the
DATA
jack) on the rear panel;
please make any needed level adjustments at the
TU side.
The Mark/Space Shift utilized in most Amateur
RTTY operation is 170 Hz. Other shifts may be
configured, however, using Menu Item “
RTY SFT
”.
The
FT-450
is set up for “high tone” operation
(centered on 2125 Hz) by default, but you may
configure it for low tone (1275 Hz) operation us-
ing Menu Item “
RTY TON
”.
You may find that you are unable to decode some
RTTY stations, even if they are of sufficient sig-
nal strength. If this is observed, there may be a
Mark/Space polarity problem between your sta-
tion and the other station. If so, try setting Menu
Item “
RTYRPOL
” to “REV” (“Reverse”) to see if
that permits copy. A separate Menu Item permits
reversal of your transmitter’s Mark/Space polar-
ity: “
RTYTPOL
.”
AF
IN
PTT
FSK
OUT
FS
K
IN
D
AT
A
O
U
T
D
AT
A
P
TT
G
N
D
INPUT
DC 13.8V
22A
ANT
GND
EXT
SPKR
CAT
LINEAR
TUNER
DATA
TU
N.C.
GND
PTT
FSK OUT
AF IN
N.C.
DATA JACK
DATA IN (Pin 1)
Pin 6
GND (Pin 2)
DATA PTT (Pin 3)
FSK IN (Pin 4)
DATA OUT (Pin 5)
SQL OUT(
)
