SITOR-A

General Information

Simplex Teletype over Radio (SITOR) is a mode for maritime communications to exchange teletype-data over a radio channel in a robust way.       
SITOR-A is the ARQ variant.

Usage:

§ Basic maritime data communication over HF.

Mode Details

 

Item

Value

Standard

Modulation

FSK

 

Number of tones

2

 

Shift (Hz)

170

 

Bandwidth (Hz)

350

 

Symbol rate (Bd)

100

 

Error correction

ARQ

 

Alphabet

ITA-2

Demodulator Settings

Demodulator

FSK 2 matched

 

Symbol rate (Bd)

100

 

SR tolerance (Bd)

5

 

Shift (Hz)

170

 

Shift tolerance (Hz)

10

 

Modem type

Synchronous

 

Min. burst length (s)

0.065

 

Max. burst length (s)

0.290

 

Min. pause length (s)

0.200

Features

Demodulation

yes

 

Recognition

yes

 

Decoding

yes

 

Automatic Polarity Adjustment

yes

 

Combination with other modems (modem list)

yes

Tuning

The tuning frequency is the center of the signal

Table 195: SITOR-A

Figure 67: SITOR-A Spectrogram