300-Baud Packet - Yaesu FT-1000MP Operating Manual

Operation
300-Baud Packet
Construct a patch cable as required, and con-
nect your TNC to the rear-panel PACKET jack. Do
not connect the squelch line (pin 5) for 300-baud
packet operation.
Tuning is very critical for F1 packet: you should
tune the transmitter and receiver within 10 Hz of
a signal to minimize repeats. The FT-1000MP
includes a few custom features to make packet
operation more convenient.
Packet Tone Pair - This offsets the center of
the IF bandpass according to the packet tone pair
you are using. If set correctly, the receiver pass-
band will remain centered on a properly-tuned
packet station when switching between wide and
narrow IF filters, minimizing the need for re-tuning
or use of the SHIFT control for re-centering.
One of four standard tone pairs can be chosen
for operation from menu selection 6-5, as desired.
The menu display shows the center frequency of
the selected tone pair (see the table below for
actual mark/space tone combinations). Set the
Packet Tone Pair to match the tones generated by
your TNC (these are usually set via terminal soft-
ware or DIP switches—check in your TNC docu-
mentation).
Packet Tone information
TNC Tone Pair Tone Center Frequency
1070/1270 Hz 1170 Hz
1600/1800 Hz 1700 Hz
2025/2225 Hz* 2125 Hz*
2110/2310 Hz 2210 Hz
* indicates default setting (used by normal convention)
Important Note! - if changing packet tone pair to
other than 2025/2225 Hz, be sure to re-calibrate
the tuning meter as outlined on page 72. The
calibration routine is simple, and ensures your
center tuning indication matches the tone pair.
Packet Frequency Display Offset - You can
display the center frequency of the two transmit-
ted carriers, (that is, the packet tone pair used),
without any offset, instead of the actual carrier
frequency. Recall menu selection 6-4 and turn the
main knob to select the offset (+3.000 kHz).
Note - The default display offset is -2.125 kHz
(to match the default tone pair* in 6-5 above, and
assuming LSB operation). Ideally, the display off-
Display Offset for Packet Operation
200-Hz
Shift
> /
Space Mark
Tone Tone
9225Hz 2025 Hz Default Packet Offset
| (tone pair center)
i -«
(14.070MHz - 2125 Hz)
2125HZ 44.070 MHz
Carrier Frequency
(suppressed)
200-Hz
Shift
' a |
Space Mark
Tone Tone
2295Hz 2125 Hz Custom Packet Offset
(adjustable)
g u naff Aan
' ~utru.uu
offset = 0.000 kHz
(adj. +/-3000 Hz)
2125HZ 14.070 MHz
Carrier Frequency
(suppressed)
set should match the default tone pair, which in
turn should match those used by your TNC. If you
would rather have the actual carrier frequency
(without offset) displayed, set the display offset to
0.000 kHz.
Packet Operation
Select the 500-Hz BANDWIDTH filter for 300-
baud packet, and press the PKT mode button
on the front panel once or twice, so that the
green LSB LED indicator lights along with the
orange PKT LED.
Transmitter adjustment is similar to SSB:
O Preset the RF PWR control counterclockwise,
and set the METER selector to ALC.
J) Now set your TNC to its "calibrate" mode, pref-
erably with both tones alternating, and adjust
the MIC control so that the meter deflects to
mid-scale.
Switch the METER selector to PO and advance
the RF PWR control for the desired power output.
When tuning, be aware that some common HF
packet channels, such as "14.103" MHz, were
originally determined to correspond with an actual
IF center frequency 1700 Hz lower (in accordance
with an old TAPR convention). Therefore, if you
have the Packet Frequency Display Offset (6-4)
set to match your TNC's actual tones, the display
shows 14.101.30 when tuned to the above fre-
quency — which is the actual center of your re-
page 55