SCS PTC-IIex, Manual

Page: 167 / 220

11 PSK31
frequency is thus not required. The transceiver connected to the PTC-IIex can operate
with the same settings as for PACTOR or AMTOR etc. The PSK31 carrier, when
correctly tuned, lies exactly in the middle of the IF filter passband. When the squelch is
open (Hot-key <Ctrl-F>), the PTC-IIex adjusts the receive carrier frequency slowly (max
approx.
±
1 Hz / 5 sec) automatically. to match that of the received signal. A manual drift
correction is not required. Refer also to chapter Hot-keys below.
11.4 Level Setting
The PSK31 output level (Transmit level) may be adjusted with the
FSKA
-command.
Normally however, the levels previously set for PACTOR/AMTOR operation can be
used, as the PSK31 peak power is the same as that produced for FSK operation. As
however the amplitude is not constant, the transmitter must on no account be over-driven!
otherwise an EXTREMELY wide spectrum is produced.
11.5 Prompt and Status
The usual Baudot-RTTY prompt is displayed, except that a P is used as an abbreviation:
**-P-** (SCSP):>
(here, SCSP is the AMTOR-selcal. This prompt addition is only
displayed for compatibility reasons). The expanded command prompt in terminal mode 5
(
TERM
command) has the code
cmd:
5, or binary 00100101. In the status-byte, refer to
Status
-command, chapter 6.91 , page 75 ), the PTC displays RTTY/CW as there are no
further free codes available here to be used.
11.6 Hot-keys
Control of the PSK31 terminal operation is done (as with the CW-terminal, refer to
chapter
6.30 , page 49 ) with so-called Hot-keys . These are specially defined control codes
produced with the <Ctrl>.
Ctrl-L: The Receive-carrier frequency is increased by 1 Hz. (Only in the receive
condition)
Ctrl - K: The Receive-carrier frequency is decreased by 1 Hz. (Only in the receive
condition)
Ctrl-X: Erases the Transmit (or type-ahead) buffer. (The PTC acknowledges the
command with "
*** CLR
".
Ctrl-C: Switches the squelch between normal operation and continuously open. In
normal operation, it is possible for even very weak PSK31 signals to open the squelch.
Switching to continuously open (
Garble on the screen, even when no PSK31 signal is
present) should only be necessary in exceptional circumstances.
When the Squelch is open, the tuning indicator displays in addition to the spectroscope
the actual demodulated PSK31 signal. In addition, the Idle, Traffic and Error LED´s
light up accordingly.
The PTC-IIex acknowledges the command with “
*** SQUELCH: ON
” or
“
*** SQUELCH: OFF
”. Default value: Squelch in normal condition (=ON).
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