Receiving NAVTEX Maritime Safety Information Broadcasts With Your Macintosh
You can apparently use any radio
tuned to 518 / 490 kHz to connect to a laptop
using the audio jack. You then need a program to decode the weather fax / satellite images
for your computer. You don't need a Pactor modem
The link above describes the process for Macs - there are similar programmes for PC's. The beauty of the above is that you just need any old radio receiver which will tune to the Navtex frequency so it's pretty cheap
to set up (multimode is $89). It isn't free though!!!