Navtex DXing

Last year I briefly tried out Navtex DXing, but then didn't keep it up, despite the encouraging results of that first experience (for instance, receiving the first station I've ever heard from Greenland). Today (Oct. 6, 2010) I decided to come back to it. Here's what I found:

• 0420 - 0425 UTC, VCK ($04C), Sept-Iles-Riviere-au-Renard, Quebec, with navigation warnings. Good signal.
• 0426 - 0436 UTC, NMA ($04A), Miami FL, with navigational notices. Weak with garbled messages, but station identifier clear.
• 0445 UTC, NMF ($04F), Boston MA, with marine weather forecast for northeastern U.S. waters. Good signal.

All these stations were logged on 518 kHz, just below the bottom end of the AM broadcast band. VCK and NMF are relogs, but NMA from Miami is a new one for me.

Navtex is transmitted in a mode called SITOR-B. To receive Navtex, you need a receiver that supports SSB reception, and a computer to decode the signal. I use a software application called Frisnet Navtex Decoder to do the decoding.

Navtex stations on 518 kHz all broadcast in English. The world is divided into regions called Navareas. The stations within a Navarea take turns transmitting according to a predefined schedule. Each station in a Navarea identifies itself by a single letter (e.g., "A"). William Hepburn, at his DX Information Centre site, has a comprehensive list of the stations in each Navarea, with their identifiers and transmission schedules.

Navtex DXers identify stations using the format $NNI, where "$NN" is the Navarea number and "I" is the station's single letter identifier. For example, $04F is station "F" in Navarea 4, and from Hepburn's station list you can see this is station NMF in Boston, MA.

I also heard an aircraft navigation beacon on 516 kHz at the same time (0420 UTC): YWA in Petawawa, Ontario, with a fairly decent signal. This station is a regular visitor here in Toronto.