Timewave DSP-232, Руководство по эксплуатации

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Chapter 12 PACTOR Operation
2. Turn any IF-shift and passband-tuning controls to their center or “off” position.
3. Adjust the volume to a comfortable listening level.
4. Enter the command
PTLIST
to monitor both linked and unlinked (unproto) PACTOR transmissions. The
PHASE and MODE L lights on the DSPs front panel should glow; you can verify you’re in the PTLIST
mode by entering
OP —the DSP will respond with:
Opmode PTList PHAS RCVE
.
5. Tune your receiver carefully between 14.065 and 14.085 MHz (or elsewhere where there’s PACTOR
activity) and listen for the 960 mS data burst of ARQ PACTOR or the steady data of the unproto mode
stations. It sounds similar to an AMTOR “cricket chirp,” but longer.
6. When you find a station, Using either the
THRESHLD
or
AUTOTHR
command, adjust the Threshold so
the DCD light goes on when a PACTOR station is being received, but goes out when no signal is received.
7. Slowly vary the tuning control on your receiver while glancing at the DSPs turning indicator. Look for the
LED pattern below and adjust the frequency control accordingly.
Frequency too low Tuned in! Frequency too high
With a good signal and your radio properly tuned in, within seconds you should start seeing text on your screen.
While receiving text, the TFC and RQ lights will blink back and forth while the MODE L light remains lit. Every
few seconds, the IDLE light will quickly blink, too. When the other station sends a CTRL+D at the end of its
message, this will “drop” the link and the PHASE and MODE L lights will be the only ones glowing; if he remains
“idle”—his transmitter is on but nothing is being sent—the RQ and MODE L lights will remain on, accompanied by
an occasional blink from the IDLE light.
Use
PTL to monitor ARQ traffic flowing between two stations linked in a PACTOR ARQ contact. Your DSP will
try to synchronize with whichever of the two linked stations has the link.
Monitoring two linked PACTOR ARQ stations doesn’t provide the error correction enjoyed by the linked stations.
Since your DSP is not part of the “handshake,” you can’t generate the request for repeat, but it will check for the
correct CRC and won’t display messages with errors. Missing blocks will be designated with four error symbols—
the default error symbol is the underline ( _ ). (See
ERCHAR
if you want to change it.)
Also, you can only read copy from the ISS station that you originally synced on—you won’t be able to hear both
sides of the PACTOR QSO unless you re-sync with the ISS after each changeover.
The DSP won’t print a block of data if that block contains the same sequence number as the previous block. If the
transmitting station (ISS) repeats the same block, the DSP won’t print it twice.
Going On The Air
Note : Make sure your DSP is adjusted for your SSB transmitter as described in Chapter 3: Radio Installation under
the heading SSB Transceiver Final Adjustments . These are very critical adjustments. If your DSPs AFSK level
and transmitter’s mike gain aren’t adjusted properly, other stations won’t be able to copy your signals.
Finally, before you go ahead and transmit, here are some helpful hints:
♦
Don’t use the VOX control—use the PTT line from your DSP.
♦
Turn off the AGC circuit—use the RF gain control to prevent receiver blocking on stronger signals.
♦
Turn off all compression or other audio processing.
♦
If you’re using an AFSK audio input, keep the audio level to the microphone input circuit as low as
possible to avoid overdriving the audio input stages.
♦
Adjust the transmitter’s drive to prevent excessive ALC action; use more effective RF antenna loading to
adjust output power levels.
Make sure your transmitter and antenna are tuned and adjusted for the band and frequency you want to use. Before
you transmit, however, you have to decide if you’re going to “call CQ” or answer someone’s CQ call.
Roundtable QSOs
September, 05 12-3