NMF Navtex on Shortwave

Today on shortwave I logged four utility broadcasts from two stations in the maritime service. All but one are relogs:

• WLO, Mobile, AL, USA on 17362 kHz at 1615-1630 UTC transmitting in SSB in English. Fair signal. Marine weather forecast. Female computer generated voice. ID for WLO and KLB at half hour, then off air.
• NMF, Boston, MA, USA on 12578 kHz at 1650-1710 UTC. Good signal. Loud and steady SITOR-B signal, which I decoded using MultiPSK. Surprised to find that it was a standard Navtex broadcast from NMF like those on 518 kHz - I didn't know Navtex was sent on shortwave as well. Meteorological conditions and navigation safety warnings. English. Good signal. New to log.
• WLO, Mobile, AL, USA on 12581.5 kHz at 1710 UTC with fair signal. Morse code/SITOR-A channel marker with WLO ID in Morse code.
• WLO, Mobile, AL, USA on 12584 kHz at 1715 UTC with fair to poor signal. Morse code/SITOR-A channel marker with WLO ID in Morse code.

Navtex on 490 kHz

In addition to 518 kHz, there are also Navtex broadcasts on 490. 518 is the main frequency and is used for English language broadcasts. 490 is used for other national languages. Today I heard a Navtex station on 490 for the first time ever. This was at 0435 UTC with a fairly good signal. Unfortunately I did not have the equipment with me to decode it so it remains unidentified.

Navtex DX Session

Results of an overnight DX session: 0310 to 1150 UTC Tues. Oct. 19, 2010. I left the receiver on overnight tuned to 518 kHz, hooked to the computer with Navtex Decoder running to see what would come in. Here's what came in. No new stations.

1. NMG ($04G), New Orleans, LA:

• 0310-0320: Navigation warnings.
• 0700-0740: Weather forecasts, two satnav messages, and some navigation warnings.

2. VCK ($04C), Sept-Iles-Riviere-au-Renard, QC, Canada:

• 0418-0425: Navigation warnings.
• 0523-0525: Meteorlogical warnings - gale warnings.
• 0610-0612: Meteorlogical warnings - gale warnings.
• 0655-0655: Meteorlogical warnings - gale warnings.
• 0818-0820: Weather forecast.

3. NMF ($04F), Boston, MA:

• 0510: Navigation warnings.
• 0844-0910: Navigation warnings and one satnav message.

And Even More Navtex DXing

I did an overnight Navtex DX session on Oct. 9. I left the computer on decoding what came in on 518 kHz and then checked it the next day. Here's what put in an appearance:

• NMF ($04F), Boston MA, 0447 - 0510 UTC, good signal with marine weather forecast for northeastern U.S. waters and four navigation warnings.
• VCK ($04C), Sept-Iles-Riviere-au-Renard QC Canada, 0601 UTC, good signal with meteorological warnings, reporting gale force winds in the Cabot Strait, Northumberland Strait, Gulf Magdalen, Chaleur-Miscou, Anticosti, etc.
• VCK ($04C), Sept-Iles-Riviere-au-Renard QC Canada, showing up again at 0654 UTC with more meteorlogical warnings.
• NMG ($04G), New Orleans LA, 0700 - 0735 UTC, fair signal with marine weather forecast and navigation warnings.
• NMF ($04F), Boston MA, 0854-0856 UTC, good signal with navigation warnings.
• XLJ895 ($04P), Thunder Bay ON Canada, 1032 UTC, good signal with marine weather forecast (for Great Lakes).
• NMG ($04G), New Orleans LA, 1102-1113 UTC, good signal with marine weather and navigation warnings.

All of these are relogs, except for XLJ895 in Thunder Bay, Ontario, which is a new station for me. As usual, I used Frisnet Navtex Decoder 2.1.5 to decode the signals.

More Navtex DXing

Another Navtex DX session and two stations received, both of them relogs. Frequency: 518 kHz, date: Oct. 7, 2010, decoding software: Frisnet Navtex Decoder 2.1.5.

• NMG ($04G), New Orleans LA, 0305 to 0315 UTC, fair signal with marine navigation warnings.
• VAR-9 ($04U), Saint John NB, 0321 to 0330 UTC, fair to good signal with marine navigation warnings.

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.

Year End Update

It's the end of 2009 so I figured I'd make one post to catch up on. Here is what I've been hearing lately:

• I added one more station to the ultralight log, bringing the count to 335. This was WORC 1310 from Worcester MA, which broadcasts in Spanish. Logged December 15.
• Did some mediumwave DXing while up in eastern Ontario over Christmas. Added four new stations to the overall log.
• I recently got interested in DXing Navtex stations on 518 kHz. These stations broadcast marine advisory information in a digital format. I set up an old laptop for decoding it and have caught a few new stations. The most noteworthy was OXI in Nuuk, Greenland. I think this is the first radio station I've ever received from that country.
• Did a bit of shortwave DXing too. Most noteworthy things logged: (a) the Royal Air Force Volmet (aviation weather) station on 5450 (SSB) from the U.K., (b) the AFRTS station on 5446.5 kHz (SSB) from Florida, and (c) several frequencies of the Saudi Arabian international broadcaster BKSKA.

And that's it for 2009.