WWV

WWV is a radio station run by the National Institute of Standards and Technology of the United States Department of Commerce. WWV broadcasts in the Shortwave, or High Frequency part of the radio spectrum, meaning that its broadcasts can be heard all around the world. It broadcasts at various frequencies, including 2.5, 5, 10, 15 and 20 MHz. Its broadcast consists of a station identification twice an hour, and then the time, repeated over and over again, along with a ticking tone. It broadcasts from near Fort Collins, Colorado, and has been broadcasting the time since 1950, although the NIST was operating the radio station in some form or another since 1919.

WWV has one of the strongest radio signals on the planet. Shortwave radios don't receive signals consistently, but WWV can be picked up by even a cheap shortwave radio. While its purpose of stating the universal time is not perhaps as important now as it was in pre-internet days, there is still something comforting and exciting to hear the time announced in a voice echoing off the ionosphere.