Specifications
11.7.3 Operating PACTOR with Other Modem frequencies and Shifts
All PACTOR operation uses 200 Hz shift FSK modems. Modem 4 (default)
is therefore the best choice for ARQ or unproto PACTOR use. The
PK-900 allows other modems to be used in PACTOR should the need arise.
The following other modems may be selected with the MODEM command.
Radio Port 1 Modems
1: FSK 45 bps 170: 2125/2295 (not recommended)
2: FSK 100 bps 170: 2125/2295
3: FSK 45 bps 200: 2110/2310 (not recommended)
4: FSK 100 bps 200: 2110/2310 (default modem RECOMMENDED)
5: FSK 100 bps 425: 2125/2550
6: FSK 100 bps 850: 2125/2975
7: FSK 100 bps 850: 1275/2125
9: FSK 2400 bps 800: 1300/2100
10: FSK 300 bps 200: 2110/2310
11: FSK 1200 bps 1000: 1200/2200
11.7.4 Automatic Speed Change
If the command PT200 is set on, the linked PACTOR mode will
automatically change the transmitted data rate from 100 bps to 200 bps
if a certain number of error-free 100 bps packets are received in a
row. If the error rate at 200 bps is excessive, the data rate will
automatically revert to 100 bps. There may be some propagation
conditions that will cause the system to vacillate between the two
data rates. This may be prevented by setting PT200 to OFF, which will
force 100 bps operation. See the UCMD command to control these
thresholds.
11.7.5 Echoing Transmitted Characters As Sent (EAS)
EAS (Echo As Sent) operates the same as in ARQ AMTOR. If EAS is on,
you will see characters echoed to your screen only the first time your
PK-900 sends them. If the data is not acknowledged by the receiving
station and is re-transmitted, the characters are not echoed again.
With EAS OFF, characters are echoed to your screen as you type them.
With EAS ON:
o If the data scrolls across your monitor at an even rate, you can
assume that you have a good ARQ link.
o If the data hesitates or scrolls in "jerky" intermittent fashion,
that's generally a sign that the radio link is not very good.
o If the characters stop appearing on your monitor, the link is
failing or has failed. The Status display will tell you this
by showing ERROR or REQUEST nearly continuously.
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