|RTTY & Facsimile Equipment|
NAVTEX (Navigational Telex) is the text transmission of navigational and weather information over radio. The primary frequency is 518 kHz, which is on the top end of the longwave band, but below the AM broadcast band. The alternate frequency of 490 kHz has also been approved for NAVTEX, and the Coast Guard is now even conducting experimental NAVTEX test on the shortwave frequency of 4209.5 kHz. These frequencies are tunable on most portable and tabletop shortwave radios. (A quality shortwave radio with CW/SSB capability is required). The information is sent in a form of radioteletype (SITOR B). Many radioteletype decoders such as the M-450 have a SITOR mode that can be used to decode and display (or print) NAVTEX.
Each transmission begins with ZCZC followed by four characters. The first character is the B1 location ID. The second character is the B2 Subject ID and characters 3 and 4 are simply the consecutive message number. The tables below will help you understand the B1 and B2 indicators.