BPM (time service)


BPM is the call sign of the official short-wave time signal service of the People's Republic of China, operated by the Chinese Academy of Sciences, broadcasting from CAS's National Time Service Center in Pucheng County, Shaanxi at, roughly 70 km northeast of Lintong, along with NTSC's long-wave time signal BPL on 100 kHz.
BPM is broadcast at 2.5, 5.0, 10.0, and 15.0 MHz, the same frequencies as WWV and WWVH, following the schedule listed below:
MHzUTCCST
2.57:30-1:0015:30-9:00
50:00-24:000:00-24:00
100:00-24:000:00-24:00
151:00-9:009:00-17:00

Transmission format

BPM transmits different signals on a half-hour schedule, modulated with 1 kHz audio tones to provide second and minute ticks:
BPM is idiosyncratic in that it transmits UT1 time between minutes 25 through to 29 and 55 through to 59, which creates an odd click-beep effect when heard below a stronger time signal station such as WWV especially when UT1 seconds are halfway between UTC seconds, close to a leap-second event.