Hal Communications ST-6000, Инструкция по эксплуатации

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4-11
The "optimum" choice between the two tone sets will vary with the application intended and
the preferences of the user. It is hoped that the previous discussion will help alleviate some of the
confusion that exists concerning the use of "low-" vs. "high-tones".
4.13.2 Transmitting AFSK Signals
Transmitting AFSK RTTY signals is much simpler than FSK signals. It is usually only necessary to
connect the tone keyer output to the transmitter audio input, adjust the tone level and transmit.
Again, however, the duty-cycle rating of the transmitter should be considered. In particular, most
VHF-FM transmitters are designed for intermittent duty and may NOT permit extended RTTY trans-
missions without reducing the transmitter power.
4.13.3 Adjustment of the ST-6000 Tone Keyer
The tone frequencies generated by the tone keyer are all derived from crystal oscillators and
therefore do not require adjustment. The audio output voltage can be adjusted with an internal
potentiometer, as explained in section 4.12. When the tones are used with SSB transmitter, the
tone level should be adjusted to produce the desired transmitter output power. When used with an
AFSK transmitter system, the tone level should be adjusted to produce the desired modulation per-
centage (AM transmitter) or deviation (FM transmitter). In all cases, avoid over-driving the trans-
mitter audio stages as this will cause distortion and transmission of spurious signals.
NOTE: DO NOT ATTEMPT TO TRANSMIT UNLESS THE PRINT SWITCH IS IN LOCAL POSITION OR
THE KOS IS ACTIVATED AS DISCUSSED IN SECTION 4.8 AND 4.9 ABOVE.