NIST radio station WWV - UTC Time

WWV is the call sign of the United States National Institute of Standards and Technology's (NIST) HF ("shortwave") radio station in Fort Collins, Colorado. 

The radio signals of WWV, WWVB and WWVH, along with the atomic clocks that their time signals derive from, are maintained by NIST's Time and Frequency Division, which is based in nearby Boulder, Colorado.[

You can hear WWV on Short-Wave Frequencies: 2.5, 5, 10, 15, 20 MHz.

WWV antenna coordinates (WGS84)
2.5 MHz 40°40′55.0″N 105°02′33.6″W
5 MHz 40°40′41.9″N 105°02′27.2″W
10 MHz 40°40′47.7″N 105°02′27.4″W
15 MHz 40°40′44.8″N 105°02′26.9″W
20 MHz 40°40′52.8″N 105°02′30.9″W

Want to check the time from your phone: 303-499-7111. This is the direct number to WWV.

Below is a clip of a short-wave recording of station WWV. 

More about WWV:

http://www.nist.gov/pml/div688/grp40/wwv.cfm

http://en.wikipedia.org/wiki/WWV_(radio_station)