One common use of utility stations is disseminating weather information. Weather information is often broadcast using
RTTY and sending
synoptic codes, or
weather charts are sent using
radiofax, which are used by mariners and others. Airports make voice weather broadcasts on
HF, known as
VOLMET. Some examples include New York Radio, which broadcasts weather information for locations in the eastern United States, or Shanwick Radio, which does the same for Europe. HF frequencies are still often used for trans-oceanic air traffic control. News agencies previously used RTTY for news stories, and, less commonly, radiofax for the images, although this is no longer done. Satellite communications and the Internet have replaced HF for this application. Many maritime radio services are often known as utility stations, including as ship-to-shore and vice versa telephony and error-correcting radioteletype such as
SITOR. Military use of shortwave is also common, but nearly all transmissions are encrypted, with voice encrypted using modes such as
ANDVT. Data transmission may make use of encrypted RTTY, use
Link-11 for radar tracking data, or use of
Automatic Link Establishment (ALE) modes to set up communication links automatically. Some utility stations are on other frequency bands, including
NOAA Weather Radio,
traveler information stations, and the like; other utility-type signals are piggybacked on
FM broadcast subcarriers. == See also ==