Sandbox:SITOR-B

SITOR-B is one of two modes of SITOR (Simplex Teletype Over Radio). NAVTEX and AMTOR-FEC/AMTOR-B uses the SITOR-B protocol. Based on CCIR 625

This mode is often used in broadcasts of navigational and other warnings from maritime stations. However, not all broadcasts are in English - for example, Istanbul Radio broadcasts in Turkish, while Olympia Radio may broadcast in Greek. This can confuse newcomers to think that their decoder is malfunctioning. See the frequencies section below for a website that lists some of these stations.

In addition, the Czech intelligence services, as well as the Egyptian diplomatic service has been known to use this mode.

Compared to SITOR-A, SITOR-B doesn't use ARQ (Automatic Repeat Request). Instead, it uses FEC (Forward Error Correction) by sending each character twice during transmission.

Sample

You may use this to fine tune your decoder:

<html5media>File:SITOR-B.mp3</html5media>

The output should be:

<source lang="bf"> ryryryryryryryryryryryryryryryryryryryryry

the quick brown fox jumps over the lazy dog

0 9 8 7 6 5 4 3 2 1

ryryryryryryryryryryryryryryryryryryryryry

ZCZC UA69 132320 UTC JAN 12 MONDOLFO RADIO

COASTAL WARNING 012/12 JAN 12 SOUTHERN ADRIATIC SEA - LECCE. DAY 13-14 JANUARY 2012 FROM 07.00 GMT TO 23.00 GMT, WILL CARRY OUT WEAPONS FIRING IN TORRE VENERIONE BOUNDED BY THE FOLLOWING POINTS:

A) 40 25 31N - 18 15 30E B) 40 30 20N - 18 16 30E C) 40 29 25N - 18 19 03E D) 40 27 45N - 18 20 58E E) 40 25 55N - 18 22 28E F) 40 23 05N - 18 23 18E G) 40 23 54N - 18 17 30E.

SAILING, ANCHORAGE AND FISHING ARE PROHIBITED. NNNN

ryryryryryryryryryryryryryryryryryryryryry </source>

Frequencies

• USCG HF SITOR broadcasts
• Worldwide HF Radio-Telex Broadcasts by William Hepburn
• Go to the very bottom of this page for additional links
• Shipcom LLC (stations WLO and KSM) have been known to send weather reports on 4214 and 8473 khz

Video Examples

• Sitor B weather broadcast from Boston
• Sitor B receiver and decoding
• Sitor B analysis and decoding

Decoding Software

Hobby Level Software

• CocoaModem (for Macs)
• MultiMode (for Macs)
• DSC Decoder
• Fldigi
• Frisnet NAVTEX Decoder
• JVComm32
• JNX
• Mscan
• MultiPSK
• SeaTTY
• Sigmira
• Sorcerer
• TrueTTY
• Yet Another NAVTEX Decoder (YAND) Scroll down to Downloads

Professional Equipment/Software

• Go2decode
• Go2Monitor
• Hoka 300-32
• Krypto500
• PC-NAVTEX
• Wavecom W-Code
• Wavecom W-Spectra
• WinRadio Advanced Digital Suite
• WinRadio Universal FSK Decoder
• Zorns Lemma German

Additional Links

• HF Digital "Tower of Babel"
• shoc Database: SITOR-B
• WAVECOM Database: SITOR-B