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Sitor-auto, Sitor-fec, Sp-14 – Wavecom W-SPECTRA (Automatic Monitoring System) V1.1.0 User Manual

Page 183

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WAVECOM Monitoring System W-SPECTRA, W-SPEED Manual V1.1.0

Transmission Modes

173

SITOR-AUTO

Fully automatic tuning to signal center, shift and transmission modes SITOR-ARQ (Mode A) and SITOR-
FEC (Mode B) may be achieved by selecting SITOR-AUTO mode.

SITOR-FEC

The SITOR-FEC mode is used in broadcast applications where a return channel is not required or unavaila-
ble. Two sub-modes are in use: General broadcasting to a number of stations and selective addressing of
only one station.

Parameter

Value

Frequency range

HF

Operation modes

FSK, Broadcast/Simplex FEC

Modulation

FSK

Symbol rate

100.0 Bd

Receiver settings

DATA, CW, LSB or USB

Input format(s)

AF, IF

SITOR-FEC transmissions are used in maritime radio communication to distribute traffic lists, news, safety
and weather information. Amateurs also use the FEC mode for calls to all (CQ calls).

The selective FEC is used when the receiving station must operate under "radio silence" conditions and
hence cannot transmit.

In most cases SITOR-FEC transmissions uses a rate of 100 Baud using the standard shift of 170 Hz.

Each character is transmitted twice with an interval of 35 bits. In the case of error-free reception of both
characters, the character is displayed on the screen. The underscore (_) character is displayed if both
characters are received in error.

SP-14

SP-14 is an AM modulated sequential 14 tone mode, which is optimized for the transmission of numeric
codes.

Parameter

Value

Frequency range

HF

Operation modes

Broadcast/Simplex

Modulation

AM, SUB MFSK-14

Speed

133.3 ms

Receiver settings

AM

Input format(s)

AF, IF

Additional Info

14.891 MHz, 14.888 MHz, 15.791 MHz, 16.291 MHz.

The tone separation is 16 Hz. The center frequency is 409 Hz and the bandwidth is approximately 210 Hz.
Each tone has been assigned a character:

 10 tones are assigned to the numerals 0...9

 One tone is used as a start character

 One tone is used as a stop character

 One tone is used as a space character

 One tone is used as a repetition indicator