CHU

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CHU
CHU.jpg
Frequencies 3330 kHzKiloHertz (kHz) 10^3 Hz3,330,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
3.33 MHzMegaHertz (MHz) 10^6 Hz
,7850 kHzKiloHertz (kHz) 10^3 Hz7,850,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
7.85 MHzMegaHertz (MHz) 10^6 Hz
,14670 kHzKiloHertz (kHz) 10^3 Hz14,670,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
14.67 MHzMegaHertz (MHz) 10^6 Hz
3,330 kHzKiloHertz (kHz) 10^3 Hz
3.33 MHzMegaHertz (MHz) 10^6 Hz
14,670 kHzKiloHertz (kHz) 10^3 Hz
14.67 MHzMegaHertz (MHz) 10^6 Hz
Frequency Range 3.33 MHzMegaHertz (MHz) 10^6 Hz3,330,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
3,330 kHzKiloHertz (kHz) 10^3 Hz
- 14.67 MHzMegaHertz (MHz) 10^6 Hz14,670,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
14,670 kHzKiloHertz (kHz) 10^3 Hz
Mode USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
Modulation OOKOn-Off Keying Modulation,FSKFrequency-Shift Keying
ACFAutoCorrelation Function
Bandwidth 2250 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).2.25 kHzKiloHertz (kHz) 10^3 Hz
0.00225 MHzMegaHertz (MHz) 10^6 Hz
2.25 kHzKiloHertz (kHz) 10^3 Hz
0.00225 MHzMegaHertz (MHz) 10^6 Hz
2.25 kHzKiloHertz (kHz) 10^3 Hz
0.00225 MHzMegaHertz (MHz) 10^6 Hz
Location Canada
Short Description CHU is a time signal radio station operated by the Institute for National Measurement Standards of the National Research Council of Canada.
I/Q Raw Recording
Audio Sample
CHU is a time signal radio station operated by the Institute for National Measurement Standards of the National Research Council of Canada.

This signal is broadcasted on three frequencies: 3 kW (3330, 14670 kHzKiloHertz (kHz) 10^3 Hz) and 10 kW (7850 kHzKiloHertz (kHz) 10^3 Hz). The transmitter is located just south of Ottawa, Canada. The signal follows a strict pattern of CWContinuous Wave beeps, along with 9 seconds where a digital time code is transmitted in a 300 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. FSKFrequency-Shift Keying mode using the Bell 103 standard, a 2225 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). tone to represent a mark (1 bit) and 2025 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). tone for a space (0 bit).

Click Here to Hear CHU Live at WebSDR in New Brunswick, Canada[edit]

Time Signal Format[edit]

Information taken from Wikipedia.

The primary time signal is a series of 300 msmilliseconds (.001 of a second) 1000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). tones, transmitted once per second, on the second. The following exceptions to the pattern provide additional information:

  • The top of the minute is marked by a half-second-long beep.
  • The top of the hour is marked with a one second-long beep, followed by nine seconds of silence.
  • The 29th second of a minute is always omitted (no beep).
  • Between one and sixteen seconds past the minute (except at the top of the hour), CHU transmits the difference between UT1 and Coordinated Universal Time (UTC) by using split tones. For positive DUT1 values from +0.1 to +0.8 s, seconds 1 through 8 are split. For negative DUT1 values from −0.1 to −0.8 s, seconds 9 through 16 are split.
  • Between 31 and 39 seconds past the minute inclusive, the once-per-second tones are reduced to 10-millisecond "ticks" while a digital time code is transmitted. The digital time code is formatted so that a Bell 103-compatible 300-baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. modem can decode it, and CHU is the only time signal station that uses this format for its time code transmissions.
  • For the last 10 seconds of each minute (seconds 50 to 59), the once-per-second tones are again cut to 10 milliseconds each, while CHU transmits a brief voice station identification, followed by voice announcements of the next minute in UTC, alternating between French and English. French announcements, using the voice of Radio-Canada news anchor Simon Durivage, are transmitted first on the odd minutes, while English announcements, voiced by late CBC Radio announcer Harry Mannis, come first on the even minutes.

Samples[edit]

One full cycle of CHU:

CHU on Leap Second, June 30th, 2016.

Frequencies[edit]

CHU currently operates on three frequencies:

  • 3330 kHzKiloHertz (kHz) 10^3 Hz (3kW)
  • 7850 kHzKiloHertz (kHz) 10^3 Hz (10kW)
  • 14670 kHzKiloHertz (kHz) 10^3 Hz (3kW)

Decoding Software[edit]

Hobby Level Software

Video Examples[edit]

Additional Links[edit]

Additional Images[edit]