HF Maritime Communications
HF Maritime Communications
HF maritime communications can be found below 30 MHz. Here's a sample of what you can hear:
- United States Coast Guard Operations
- Weather broadcasts, using voice, data or weather charts (FAX). The HFFAX.de website run by Marius Rensen with extensive HF and satellite FAX information
- NOAA Maritime Products The place to begin to find schedules for SITOR and FAX stations from the US and elsewhere
- 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. The use of these frequencies has gone down drastically over the years due to cell phone, satellite and other technologies
- 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
What Equipment Will I Need to Hear these Stations?
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.
A few magazine publications have columns devoted to HF logs (including maritime stations)
submitted by readers. This is a great way to discover to what other people are
listening. These logs will often include multiple entries for the same
frequency, which means that frequency has been active. However, keep in mind
that, due to publishing constraints, there is often a 60 or 90 day lag between
when the report is received and when it's actually published.
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 Utility Monitoring Central Software page for a list of these packages.