66
FT-857 Operating Manual
ating on 1200 bps, try now to connect to another station or node; you may well find that the
drive level needs no further adjustment. If, however, you are having trouble connecting due
to insufficient or excessive drive from the TNC to the
FT-857
, use Menu Mode
No-071
[
PKT 1200
]
(for 1200 bps Packet) or
No-072
[
PKT 9600
]
(for 9600 bps Packet) to set the
drive. Use your terminal software’s “test” protocol to send out test tones, and adjust the
deviation by rotating the
DIAL
knob, which will vary the data input level to the
FT-857
’s
modulator. Remember to press and hold in the [
FUNC
] key for one second when adjust-
ments are completed, so as to save the new setting for Menu Mode
No-071
[
PKT 1200
]
or
No-072
[
PKT 9600
]
.
The 9600 bps Packet deviation setting is very critical to successful operation, and
it can only be accomplished using a calibrated deviation meter; the optimum set-
ting is usually ±2.75 kHz (±0.25 kHz). For 1200 bps, the optimum level is much less
critical, with the optimum deviation being between ±2.5 kHz and ±3.5 kHz.
W
EATHER
F
AX
M
ONITORING
Monitoring of HF WeatherFax broadcasts is easily accomplished using the
FT-857
.
Before proceeding, be certain that the WeatherFax demodulator is
properly connected to Pins 5 and 2 of the rear panel
DATA
jack.
1. Set the transceiver to the VFO mode, and set the operating mode
to “DIG,” setting Menu Mode
No-038 [DIG MODE
]
to “
PSK31-U
,” as described previ-
ously.
2. Now, select the operating frequency of the station transmitting the WeatherFax broad-
cast. Note that, in the USB mode, the frequency you should program onto the display is
typically 1.90 kHz below the station’s “assigned” frequency. Thus for a WeatherFax
station assigned to 8.682.0 MHz, tune to 8.680.1 MHz.
3. When the WeatherFax broadcast begins, no further operator intervention should be needed
from the transceiver standpoint. The audio level from the
DATA
jack on the rear of the
transceiver is fixed, and cannot be adjusted.
4. Fine adjustments in the gray-scale and the frame alignment are accomplished using the
computer and software connected to your WeatherFax demodulator.
P
ACKET
(
1200/9600
BPS
FM
)
O
PERATION
T
RANSMITTER
O
PERATION
DATA
DATA OUT
GND
