A beacon is a type of device that draws attention to itself by emitting light or electric signals. It is often installed at places where visibility may be limited, such as airports or at sea. It can have different applications, but is most commonly used to warn of danger or signify an alarm.
Historically, beacons have been used for a very long time. Some of the first beacons were fires that were lit and scattered through forts and posts on mountain ranges. In many towns and villages, they were used to warn of incoming enemy attacks. At night these flames were easily spotted, while during the day the smoke from them was more visible. Beacons were also utilized to send coded messages through chain systems, where they were aligned in rows stretching long distances and lit one by one.
Today, aerodrome beacons are used at airports, and are often stationed above the control tower. These lights help airplanes find the airfield at night or during stormy weather. Many beacons use different color combinations to transmit messages to the pilots. They can also change their rate of flashing to warn of possible danger.
Another common and well known type of beacon is used at lighthouses. These buildings have been employed for centuries to aid marine navigation. They are often tall and send out bright beam of light, generated by a huge lamp at the very top of the tower. A lighthouse beacon not only helps sailors find destinations, but can also be used to mark dangerous spots covered by water, such as reefs and shallow water. In the past, many of these towers required a person inside to operate the beacon, but most today are automated.
Electric radio beacons are a different type of beacon that emits radio waves to signify location. Distress beacons like this can be sent out by ships and airplanes to call for help. They generally work on the same principle as light beacons, but send out invisible signals that can only be detected by another radio that is tuned to the right frequency or station. One of the main advantages of this type is that they can reach great distances.
While most beacons are used as alarms, they can also mark special occasions and events. For instance, light beacons can be lit on certain holidays, such as New Year's Day, to acknowledge the celebration. They can also be used to signify the beginning of a month or the start of a season.