A shortwave band is a frequency band within the radio spectrum. Many people are not readily familiar with this broadcast band, because it is not typically listened to or used for communication in most households. Advancements in technology in the area of cell phones and the Internet have also limited the use of shortwave broadcasting. The shortwave band does transmit a plethora of information, however, and it is a reliable means of communication, especially during hazardous situations and for areas that have limited technology.
The shortwave frequency travels in a range between 3 Mhz and 30 Mhz. This band is designed to travel long distances and transports news and entertainment, as well as government information. The radio band that most people are familiar with is the band that broadcasts on FM and television stations. These bands are intended to travel short distances, usually 50 to 75 miles (80 to 120.7 km), and can be picked up by regular radios and televisions.
The shortwave radio band is able to bounce off the ionosphere during all hours of the day. The lower end of the shortwave band transmits a stronger signal at night and the upper end of the band works better during the daylight hours. Shortwave broadcasters often adjust their frequencies depending on what time of the day they are broadcasting.
The way the shortwave radio band interacts with the ionosphere is what allows broadcasts to travel around the world. Shortwave bands are also picked up and relayed by different outposts on different continents. These relay stations transmit the broadcasts from point to point, and are able to boost shortwave signals.
The shortwave band frequency cannot be picked up by a regular FM/AM radio. Specialized shortwave radios are needed to pick up transmissions on the shortwave band. These radios can pick up amateur or ham radio signals; signals from the World Band Radio, which include the Voice of America and BBC; and signals from boats and aircraft. Weather broadcasts are also very popular via shortwave; these broadcasts inform listeners of local and regional forecasts and weather emergencies.
Within the shortwave band there are frequency ranges similar to those on the FM radio. Like a radio station that broadcasts on a certain station, each of these shortwave broadcasters operates on different radio frequencies. The shortwave radio band is regulated for use by governmental officials, and each broadcast frequency is determined by a country's government.
Anyone with a shortwave radio can monitor the shortwave band. For this reason, it is important that personal information is not broadcast across its waves. Only people who have been licensed are allowed to legally transmit information using the shortwave radio band.