National Institute of Standards and Technology radio station WWVB(AM) plans to conduct more tests in an effort to improve its signal penetration.
The station near Fort Collins, Colo. will test a phase-modulated broadcast format beginning at noon Mountain time on Tuesday, Aug. 21 and ending at noon Mountain time on Friday, Aug. 24.
WWVB continuously broadcasts time and frequency signals at 60 kHz. The carrier frequency provides a stable frequency reference traceable to the national standard. WWVB is also used for high level applications such as network time synchronization and frequency calibrations.
During the test period the broadcast will randomly switch between the normal WWVB broadcast and the new phase-modulated broadcast format, according to station Broadcast Manager John Lowe.
Radio-controlled clocks and watches will not be affected by the test. However phase-locking 60 kHz timing and frequency standard receivers may lose lock during the test, but will restore during the normal broadcast period, according to Lowe.
The station conducted similar tests in June.