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Courtesy of the U.S. Coast Guard

Radio fax, also known as radio facsimile or weather fax, is a means of broadcasting graphic weather maps and other graphic images via HF or shortwave radio. Maps are received using a dedicated radio fax receiver. Pictures can also be received using a single sideband shortwave receiver connected to an external facsimile recorder or PC equipped with a radio fax interface and application software.

The National Weather Service (NWS) radio fax program prepares high seas weather maps for broadcast via four U.S. Coast Guard (Boston, New Orleans, Pt. Reyes, and Kodiak) and one DOD transmitter site (Honolulu). These broadcasts are prepared by the Marine Prediction Center, Tropical Prediction Center, Honolulu Forecast Office. and Anchorage Forecast Office. Limited satellite imagery, sea surface temperature maps and text forecasts are also available. The International Ice Patrol also broadcasts radio fax charts from Boston sharing the same transmitters.

The U.S. Navy terminated all regularly scheduled radio fax transmissions with the exception of the Mediterranean beginning January 1, 1998. The system is operated in a back-up mode for on-demand service by fleet units upon request. Previous plans to permanantly terminate the Navy radio fax program by January 1, 1999 were under review and no additional information is currently available on the status of that program. These transmissions are to meet the requirements of the U.S. military and have no direct connection to the National Weather Service's radio fax program.

Table 1 below is an abbreviated version of the NWS radio fax broadcast schedules. All radio fax broadcasts of National Weather Service products employ a radio fax signal of 120 lines-per-minute (LPM) and an Index-of Cooperation (IOC) of 576. These values must be entered into the users equipment or software program in order for the radio fax image to be displayed properly.

Radio Fax Broadcast
Boston, Massachusetts (NMF): 6340.5, 9110 and 12750 kHz 
Start Broadcast 0230Z   0800Z   1430Z   2005Z
Broadcast Schedule      0243Z   1903Z   
Ice (Seasonal, ~Feb- Sep)       1600Z1  1810Z1
1 International Ice Patrol, call letters NIK. 

New Orleans, Louisiana (NMG): 4317.9, 8503.9 and 12789.9 kHz 
Start Broadcast 0000Z   0600Z   1200Z   1800Z
Broadcast Schedule      0630Z   1830Z

Kodiak, Alaska (NOJ): 2054, 4298 and 8459 kHz
Start Broadcast 0400Z   1000Z   1800Z   2200Z
Broadcast Schedule (Mon, Fri)   1838Z

Point Reyes, California (NMC): 4346 (except 2300Z), 8682, 12730, 17151.2 and 22527(2300Z) kHz 
Start Broadcast 0245Z   0815Z   1100Z   1415Z   2015Z   2300Z
Broadcast Schedule      1104Z   2324Z

Honolulu, Hawaii (KVM70): 9982.5, 11090, 16135 and 23331.5 kHz 
Start Broadcast 0533Z   1150Z   1733Z   2350Z
Broadcast Schedule      0533Z   1150Z   1733Z   2350Z
(Note: National Weather Service station, not U.S. Coast Guard)

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