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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)