Today, I received a QSL card from the National Time & Frequency Institute's BPM shortwave time signal station. Below is an introduction for HAMs on how to obtain their own QSL cards.
The Time Center relies on amateur radio enthusiasts around the world who monitor time signals and report their observations to the Time Center. This information helps the Time Center understand how radio waves propagate globally, and this activity is a favorite pastime for many HAM radio enthusiasts.
The National Time and Frequency Center (formerly the Shaanxi Astronomical Observatory) is located in Lintong, Shaanxi Province, a central region of China. It is responsible for establishing and maintaining China's standard time, and uses various methods to synchronize with international time standards. Established in 1966 with approval from the State Science Commission, and shortwave time signal broadcasting trial started in 1970 with approval from Zhou Enlai; officially broadcasted standard time and frequency signals in 1981 with approval from the State Council and Central Military Commission. In the early 1970s, to meet the needs of China's rocket launches, control, and space technology development, the State Council and Central Military Commission approved the construction of a longwave time signal station at the Shaanxi Astronomical Observatory.（BPL）In 1986, after passing a national-level technical assessment organized by the State Science Commission, it was officially broadcast at standard time and frequency.
National Time Center website QSL card content
A QSL card is a radio signal reception confirmation card that is created by a radio station according to international practice. After the National Time Center's BPM shortwave time signal broadcasting station was built and tested in 1970, it began printing the first version of the QSL card. For more than thirty years, it has provided confirmation for thousands of amateur radio enthusiasts around the world who listen to BPM, while the "receiving reports" from all over the world have played a good role in analyzing the broadcasting situation and promptly discovering problems of BPM signals. The National Time Center has always attached great importance to the collection and analysis of BPM shortwave "receiving reports," and according to international practice, it promptly sends QSL cards to amateur radio enthusiasts. Today, the 30-year-old lead-plate printed BPM shortwave receiving card is far behind the development of the times. The National Time Center has officially launched a new version of the QSL card.
Knowledge Tip: "QSL" is an abbreviation for "I have received your message" in the Q code used for communication. A QSL card is a certificate created by various radio stations internationally to confirm receipt of messages. There are many amateur radio enthusiasts worldwide who actively listen and record information such as call signs, frequencies, and communication modes of different radio stations, and then send reception reports to the stations. According to international conventions, radio stations should promptly send QSL cards to these enthusiasts to acknowledge their reception reports. Collecting QSL cards from various radio stations is like collecting stamps, attracting many amateur radio enthusiasts. All enthusiasts strive to collect as many cards as possible from different countries and regions.
Related information about the Time Tower
1. Shortwave time synchronization
Radio call sign: BPM
The shortwave band, which uses frequencies between 3 MHz and 30 MHz, corresponds to wavelengths ranging from 100 meters to 10 meters.
Broadcast frequency and time:
2.5 MHz AM mode, Beijing time 15:30 - 09:00
5 MHz AM mode, Beijing time 0:00 - 24:00
10 MHz AM mode, Beijing time 0:00 - 24:00
15 MHz AM mode, Beijing time 9:00 AM - 5:00 PM
Completion date: 1970
Launch location: Pucheng County, Shaanxi Province
Coverage radius: The coverage radius of shortwave time signals exceeds 3000 km. Different frequencies are broadcast alternately to cover the entire territory of China.
Starting approximately half an hour or a minute before the top of the hour, Morse code and female voice broadcasts begin, with content such as "--. -- (BPM)". This is usually repeated several times before a human voice announces the message. The female voice broadcast is very important, so please listen carefully and record it accurately.
Why do the "beeping" sounds of shortwave time signals sometimes have long durations and sometimes have short durations?
The BPM shortwave time signal synchronizes with UTC (Coordinated Universal Time) by modulating a carrier signal with 10 cycles of a 1 kHz sine wave, producing an audio signal that is 10 ms long. The UT1 second signal also produces a 100 ms audio signal in the same way. Both the full-scale signals of UTC and UT1 use 300 cycles of a 1 kHz sine wave to modulate the carrier signal, resulting in a 300 ms audio signal.（0）The starting points for the audio signal's first wave, as well as the shortwave and full-wave signals, are all at the beginning of the audio signal's first wave. Therefore, shortwave users can hear the "tick-tock" sound through their receivers, and the lengths of the short, full, and UT1 sounds are noticeably different due to the difference in the length of the audio signal.
Content broadcast at different times within 60 minutes
59:00 - 59:40, record power code call sign, BPM (duration 40 seconds)
59 seconds 40 seconds - 60 minutes 00 seconds, transmit call sign and voice content. (Duration: 20 seconds)
0 minutes 0 seconds - 5 minutes 0 seconds, send coordinated time.（UTC）The second signal
05:00 - 10:00, transmit Coordinated Universal Time (UTC)（UTI）The second signal
10:00 - 15:00, transmit an unmodulated carrier signal, with no audio.
15:00 - 25:00, transmit Coordinated Universal Time (UTC) seconds signal
2:50 - 3:00, transmit WWVB time signal
29:00 - 29:40, record power code call sign, BPM (duration 40 seconds)
29 minutes and 40 seconds - 30 minutes and 00 seconds: Send out the call sign and voice content. (Duration: 20 seconds)
2、 Long-wave time synchronization
Radio call sign: BPL
The kilometer band, which refers to the frequency range of 30 kHz to 300 kHz (wavelength: 10 km to 1 km), is a longwave band.
Construction date: Completed in 1979, timekeeping started in 1983.
Transmission frequency: 100 kHz
Radiation power: 800 kilowatts
Broadcast time: Daily, from 13:30 to 21:30 Beijing time (using the new time published by the Time Center as the standard)
Launch location: Pucheng County, Shaanxi Province
Coverage radius: The ground-based transmission range of longwave time signals is 1000-2000 km, and the skywave signal range is 3000 km. This covers most of mainland China and nearby coastal areas. The time synchronization accuracy is in the microsecond level.
3、 Time synchronization using low frequencies
Radio call sign: BPC
Low-frequency time transfer systems typically refer to longwave time transfer systems that operate in the fifth frequency band (frequency: 30-300 kHz). A low-frequency time transfer system is a wideband FM radio broadcasting system with a carrier frequency of 68.5 kHz.
Completion date: 2007
Transmission frequency: Uses a continuous wave pulse code timing system with a carrier frequency of 68.5 kHz.
Radiation power: 100 kilowatts;
Broadcast time: Broadcast for 21 hours every day, with a downtime of 5:00 AM to 8:00 AM Beijing time for maintenance (refer to the new broadcast schedule released by the Time Center).
Launch location: Yuyang County, Shangqiu City, Henan Province
Coverage radius: Terrestrial wave stable coverage radius of 1000 km, satellite wave coverage radius of 3000 km.
The common radio clocks and frequency counters we use can receive this signal and automatically perform time calibration. The accuracy can reach within 1 second of an error of 3 million years.
Reporting Content and Methods
Dear National Time Center BPM Shortwave Time Signal Station Administrator:
During the BPM short pulse time synchronization frequency, a successful time synchronization signal was received. The content of the signal report is as follows:
As of date received: 2021/3/6
Beijing time: 21:50 - 22:05
Receiving location: No. 888, Chang'an District, Shijiazhuang City, Hebei Province
Using the device: De Sheng BCL3000
Antenna to be used: 1.5m telescopic antenna (ground height, altitude 85 meters)
Operating frequency: 5000 KHz
Received content: BPM, XXXX, XXXX, XXX
Reception effect: Microphone to 9 levels, slight low noise, broadcaster's voice clear and intelligible.
Receiver operator (call sign): BD3OOX (or name)
Contact Information: The following is the address to which you can send your QSL card.
My address:
Name:
Phone:
Email:
Postal code:
I hope to receive your QSL card.
Reporting methods: Via email (recommended), regular mail, registered mail, express delivery, etc.
Please be sure to accurately report the signals and content you hear, without providing false information through other channels. This is the basis for the timing center to understand the spread situation. Especially when describing the reception effect in detail. If you have the ability to record audio or video, you can record the received signal and send it with a time-labeled filename (of course, if recording is not possible, you don't need to). For example, if the "Beijing Time" listening period is 15 minutes, then record for 15 minutes.
Shipping address
Address: PO Box 18, Lintong District, Shaanxi Province, China; National Time and Frequency Center, Chinese Academy of Sciences
Postal code: 710600
Contact person: Liu Changhong
Email address:
Email:ch117@ntsc.ac.cn
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