HF Maritime Communications
From The RadioReference Wiki
HF Maritime Communications
HF maritime communications can be found below 30 MHz. Here's a sample of what you can hear:
- Canadian Coast Guard-Radio Aids to Navigation
- HF Underground Maritime Weather Transmissions
- HF Underground Maritime FAX Transmissions
- United States Coast Guard Operations
- United States Coast Guard MF & HF Channel Information page has several frequency lists.
- Weather broadcasts, using voice, data or weather charts (FAX). The HFFAX.de website run by Marius Rensen with extensive HF and satellite FAX information
- Numerous ship-shore HF frequencies exist in the 2, 4, 6, 8, 12, 16, 18 and 22 Mhz bands. Some are simplex (ship and shore on the same frequency) while others are duplex (ship on one frequency, shore on another). See this website for a complete list. These frequencies are all but dead due to cell phone, satellite and other technologies, but remain on the books.
- Fishing Fleets (some using illegally modified ham HF gear)
- Dockside Radio Interesting place to find HF frequencies, both ham and marine for various support nets
- Hugh Stegman's Hurricane Frequency List
- When a hurricane (cyclone in the Pacific) is spotted, the Tropical Cyclone Plan of the Day will give you an idea of when the flights to track these storms will take place
What Equipment Will I Need to Hear these Stations?
- See our The HF Utility Receiver and Accessories article for a discussion of this topic.
How to Find Activity?
The spectrum for HF maritime communications is very wide. Unlike VHF/UHF scanning, it's challenging to automatically scan a segment of the band because HF noise will always be present. While some maritime stations are on a fixed schedule, others (such as fishing fleets) are much more difficult to detect due to their transient nature; thus, listening for maritime comms can be a game of patience. The more time passes, the harder it is to hear again. Mailing lists are one of the best ways to keep ahead of what is being heard, as traffic can be passed relatively quickly. The Utility DXers Forum is very active and is only one of many such lists; more are available on the Utility Monitoring page.
The Spectrum Monitor Electronic Magazine is the only remaining hobby level magazine that publishes logs from its subscribers. Most others have gone by the wayside, having been supplanted by many web-based sites - which may or may not have up to date information.
Digital and other modes
While many ships are now using encrypted digital signals for email and other traffic (often using modified versions of PACTOR-II or III), there is still a great deal of traffic in the clear. This includes SITOR-B weather broadcasts, FAX (Fascimile weather charts), GMDSS alerts and more. Fortunately there are numerous software packages - some ham related, others not - that can decode some or all of these modes. See the DXing Digital Utilities article for a list of these packages.
See the Testing Your New Setup article for links to scheduled SITOR-B (NAVTEX) and FAX schedules