Yaesu FT-8800R Operating Manual page 13

Note that 9600 bps packet transmit-deviation adjustment is very critical to successful op-
eration, and can only be accomplished using a calibrated deviation meter (such as that
found on an FM Service Monitor used in a communications service center). In most cases,
the Packet Data Input level (set via a potentiometer inside the TNC) must be adjusted to
provide a deviation of ±2.75 kHz (±0.25 kHz). Check with your packet node's sysop if you
have any questions about the appropriate deviation level for your network. Note also that high
throughput on 9600 bps frequently requires strong signals, so you may wish to consider the use
of a directional antenna such as a Yagi for communication with high-speed packet nodes.
The setting of the 1200 bps Packet Data Input level is much less critical than it is at 9600 bps,
and satisfactory adjustment to the optimum (±2.5 ~ ±3.5 kHz) deviation can usually be done
"by ear" by adjusting the TNC's 1200 bps TX Audio Level potentiometer so that the outgo-
ing packets (as monitored on a separate VHF or UHF receiver) are approximately the same
level as (A) the DTMF tones or (B) the 1750 Hz Burst tone produced using the microphone.
Finally, note that the Menu ("Set") mode allows you to set the Packet data rate (1200 or
9600 bps) independently for each band, and set the Packet Receiving Band (Main band,
Right band, or Left band: Transmit band is fixed on Main band). If you have trouble getting
your FT-8800R to respond correctly during packet operation, check to be certain that you
do not have Menu #26 (PKT.SPD
set to the wrong operating band.
ANT
ANT
FT-8800R Operating Manual
B S
ASE TATION
PKT.SPD) set to the wrong data rate, and/or Menu #27 (PKT.RXB
PKT.SPD PKT.SPD PKT.SPD
13.8VDC
EXT SP
DATA
9600bps Packet Setup
13.8VDC
EXT SP
DATA
1200bps Packet Setup
I
NSTALLATION
I
NSTALLATION
DATA
OUT
DATA IN
GND
DATA OUT
(9600bps)
PTT
DATA
OUT
DATA IN
GND
DATA OUT
(1200bps)
PTT
PKT.RXB) PKT.RXB PKT.RXB PKT.RXB
DATA
IN PTT
DATA
IN PTT
11