NIST, the American National Institute of Standards and Technology are responsible for many things but one service which as radio amateurs we may associate to them is the broadcast of time and frequency information 24 hours a day from their radio station, callsign WWV, in Fort Collins, Colorado.

The information broadcast includes time announcements, standard time intervals, standard frequencies, UT1 time corrections, a BCD time code, geophysical alerts and marine storm warnings.  The transmissions are in the HF part of the radio spectrum and are powerful.  Transmissions on 5, 10 and 15MHz are at 10kW and 2.5kW on 2.5 and 20MHz.  Its worth noting that transmissions are DSB with AM modulation.

In the UK we can hear these transmissions depending upon time-of-day, ionospheric conditions and frequency.  They are RF frequency precise and thus can be used to check the alignment of a receiver amongst other things.

Recently WWV has started transmissions again on 25MHz radiating 1kW from a monopole.

For more information on WWV, including its history, images and a FAQ click here.

Have a listen on precisely 5, 10, 15, 20 or 25MHz and see what you hear 😉

Andrew
G0RVM