PK-232 MBX Operating Manual - N3UJJ

PK-232 OPERATING MANUAL
SIAM AND TDM OPERATION
CHAPTER 10
SIGNAL IDENTIFICATION AND TDM OPERATION
10.1 Overview
As you tune across the High-Frequency bands these days you find an
ever increasing number of digital signals. These signals range from
the simple Murray Baudot code, to ASCII and even packetized data.
With the large number of speeds, formats and shifts now in use, it is
difficult to say the least, to determine what kind of signal you are
listening to. Even with a knowledge of digital communications, it is
still time consuming to set the communication parameters correctly.
SIAM stands for SIgnal Identification and Acquisition Mode, and allows
a wide variety of digital signals to be automatically analyzed so they
can be easily copied with the PK-232. SIAM will "listen" to a signal
for a few seconds and then display the type of signal and its speed
to the user. The user can then decide whether or not to copy the
signal, or simply go on to the next.
SIAM makes the PK-232 more useful to the radio amateur and the Short-
Wave Listener alike. Whether tuning across 20 meters, or searching
the Short-Wave bands, when you find a signal SIAM will help you decide
what it is, and tune it in without time consuming trial and error.
10.2 SIAM Operation
When preparing to tune in a digital signal, the only decision the
operator needs to make before entering the Signal analysis mode is
whether the signal is narrow or wide shift.
The command WIDESHFT determines whether or not the filters in the
PK-232 are set for copying signals with a frequency-shift of greater
than 200 Hz (WIDESHFT ON) or a shift of 200 Hz or less (WIDESHFT OFF).
Inside the Amateur bands most signals will be using 170 or 200 Hz
shift and so WIDESHFT should be OFF. Outside the Amateur bands most
stations will be using a frequency shift of more than 200 Hz and so
WIDESHFT should be set ON.
10.2.1 Tuning in FSK Narrow and Wide Stations
Tuning in the Frequency Shift Keying (FSK) signal properly is critical
to successful SIAM operation. SIAM can only decode a signal properly
if it is tuned correctly. Follow the tuning procedure below carefully
for the best results in tuning HF FSK stations.
o
o
o
Make certain your HF receiver is either in LSB or FSK depending
on your PK-232 setup.
Turn any IF-Shift and Passband-Tuning controls to the Center or
OFF position.
Tune your receiver carefully across the band looking for the
distinctive two tone sound of an FSK signal.
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