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 34°56′55.96″N 109°32′34.93″E / 34.9488778°N 109.5430361°ECoordinates: 34°56′55.96″N 109°32′34.93″E / 34.9488778°N 109.5430361°E, roughly 70 km northeast of Lintong,[1] 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:[2]
| MHz | UTC | CST |
|---|---|---|
| 2.5 | 7:30-1:00 | 15:30-9:00 |
| 5 | 0:00-24:00 | 0:00-24:00 |
| 10 | 0:00-24:00 | 0:00-24:00 |
| 15 | 1:00-9:00 | 9:00-17:00 |
Transmission format
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Sample of BPM time signal
 The BPM time signal, recorded at 2007-01-07 in Beijing |
| Problems playing this file? See media help. | |
BPM transmits different signals on a half-hour schedule, modulated with 1 kHz audio tones to provide second and minute ticks:
| Minute | Duration | Transmission | |
|---|---|---|---|
| 00 | 30 | 10 | UTC: 10 ms second ticks, 300 ms minute ticks. |
| 10 | 40 | 5 | Carrier (no time code) |
| 15 | 45 | 10 | UTC: 10 ms second ticks, 300 ms minute ticks. |
| 25 | 55 | 4 | UT1: 100 ms second ticks, 300 ms minute ticks. |
| 29 | 59 | 1 | Station identification: Morse call sign for 40 seconds, then voice announcement "BPM 标准时间标准频率发播台" ("BPM standard time, standard frequency transmission station") twice for 20 seconds. |
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.[4]
References
- ↑ "National Time Service Center: Facilities".
- 1 2 "短波授时台". National Time Service Center.
- ↑ Marco1971 (2007-01-23). "Re: A question about Wave Ceptor frequency reception". Retrieved 2011-04-29.
- ↑ "HF (SW) Radio - Time NZ & A".
External links
- National Time Service Center
- 短波授时台(Shortwave time signal station), from the National Time Service Center, Chinese Academy of Sciences
