[GreenKeys] NAVTEX Service/AEA Decoder Pakage

[Lawless, Loveless & Childress]

NAVTEX gear is a part of GMDSS and is required carriage equipment aboard 
vessels of countries signatory to the SOLAS Treaty.  It is another "Box 
of Diodes" designed to eliminate the  Radio Officer billet aboard ship. 
The receivers aboard ship are usually smaller than a cigar box and print 
their received text on roll paper like that of adding machines, and are 
mounted in the Wheelhouse.

In the Red Sea, Persian Gulf, Eastern Mediterranean and the waters 
around Korea, we usually turn it OFF because of the continual false 
and/or repetitive alerts.

Read all about it in NATIONAL GEOSPATIAL INTELLIGENCE AGENCY Publication 
117, available from your government, but not for free.

Or, find a Second Mate or Chief Mate on the beach, buy him two cold 
beers, and in 30 minutes you'll know as much about it as anyone else.

NAVTEX groundwave signals travel from the shoreside stations well 
inland. I copy the station in the LA area easily here in the Las Vegas 
Valley.

The PK-232 decodes it handily, treating it as an AMTOR FEC signal. In 
the business, SITOR is the working name for AMTOR. Same signals and 
logic, works the same way, invented by Peter Martinez, if I recall 
correctly. If using the PK-232, no special software is required, just a 
common terminal emulator fed by the PK-232. Even a dumb terminal would do.

All the "content" is text, FYI, and it is just the rehashing of the 
current Notices to Mariners for the area near the transmissing station 
and some regional marine weather forecasts. Most of this is about as 
exciting as watching grass grow, unless you're at sea and even then, the 
information comes aboard sooner via INMARSAT.

If reading NAVTEX broadcast content  thrills  you for more than ten 
days, AT  MOST, might I suggest Professional Counseling?  Even people 
who get paid to read this stuff hate it.

::::

AEA used to make a softare/hardware package, back about 1988 that 
consisted of a couple of diodes in a plastic D-series hood, a line to 
SPEAKER audio and a floppy. It could/would decode:

FEC AMTOR/SITOR (not really well)
RTTY (not really well)
CW (really poorly)
WEFAX MAPS (adequately, if one had a stable, Quality Receiver and a 
careful  touch).

The thing ran under DOS on a 286,  so it wasn't  crunching  Hawking 
numbers. These occasionally turn up on eBay. $25 would be my Top Price  
for one.

I used to carry one aboard ship in the pocket of my Laptop Bag. Plug it 
into the 600 ohm output of a MacKay/Dymek 3010 receiver and the FAX copy 
on HF was very clear and high-contrast on the laptop screen. Several 
Captains I saild with preferred it to the hard copy product from the 
ship's Weather  FAX gear because I could copy a series of maps off the 
air, SAVE them to a floppy, and they could gawk at them at their leisure 
in theor Day Rooms.

It was a real, "Wow the Whuffoes!!!" thing about 1994 or so.

RGDS DE BUCK,  W7LV   US Merchant Marine Radio/Electronics Officer