February 28, 2007 10:55
Quote: SNIP http://www.wetterinfobox.com/english/index.htm
SNIP
The only disadvantage I can see with this device is that it doesn't output the standard serial stream of other Navtex decoders such as the Nasa engines which some charting programs use to integrate Navtex warnings into their systems (see my earlier post requesting this functionality in MacENC! Wink )
For those of you, like myself, who are clueless about Navtex may I recommend this link, and all of the PDF documents and further links on that site:
http://www.beaconworld.org.uk/navtex.htm
If that is too much information, I offer this from:
http://www.w3eee.com/navtex.html
What is Navtex?
"Navtex" is an informational data broadcast system for shipping; anything from weather warnings, missing or overdue boats, ice warnings, and anything which may be considered a hazard to shipping.
The transmissions are from fairly powerful stations dotted around the coastline, with largely overlapping coverage. The main transmission frequency is 518kHz, just off the end of the AM broadcast band, with a secondary LF frequency of 490kHz less used. Additionally, there is an HF channel at 4209.5kHz. The signals themselves are 170Hz Frequency Shift Keying (FSK) centered on the nominal frequency (i.e. one carrier is 85Hz below, the other 85Hz above) and at a rate of 100 bps. Data is sent 'Forward Error Corrected' (FEC), which means the same characters are sent twice, one a few characters before its repeat, interleaved with subsequent data. Tuned in with a receiver set to SSB, it sounds like a high-speed 'burbling'.