| 词条 | Beta (time signal) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 释义 |
Beta is a time signal service in the VLF range in Russia, operated by the Russian Navy.[1] It is controlled by All-Russian Scientific Research Institute for Physical-Engineering and Radiotechnical Metrology[2]. There are 6 transmitter stations, which take turns transmitting time signals and other communications. Although the transmitters are active 24 hours a day, each transmits the time code one hour per day. Beginning on the hour is 25 minutes of 25.0 kHz, including morse code station identification and time code. This is followed by 5-minute intervals of 25.1, 25.5, 23.0 and 20.5 kHz. No time code is sent during the last quarter of an hour. The Beta networkBeta consists of the following transmitters: [3]
Frequency usageThe time code consists of a series of signals on multiple frequencies. Transmission starts on the hour. Each time a new frequency is selected, there is 1 minute of low power while the transmitter is adjusted, then full-power transmissions begin. The transmitters are estimated to operate at 1000 kW, achieving 30–50 kW EIRP. (The difference is due to the low efficiency of antennas at this frequency, which must be much smaller than the 12 km wavelength.)
The time code consists of a series of carrier pulses:[6]
The hour or date is not coded. Most of the stations were built in the 1970s. RJH63 and RAB99, built later, has a different transmission:
See also
References1. ^C3 Systems of the CIS Navy {{webarchive |url=https://web.archive.org/web/20111005174016/http://www.astrosol.ch/networksofthecisforces/vlfmorsedigmodenetwork/5379039f1707a4601/index.html |date=October 5, 2011 }} 2. ^{{Citation|url=ftp://ftp.vniiftri.ru/BULLETINS/V/bull_b16_2018.pdf|format=PDF|title=Standard Time and Frequency Signals|accessdate=2018-07-15}} -- official signal specification, in russian. 3. ^{{cite book| author=Marten, Michael| title=Spezialfrequenzliste 2007/08, band 2| publisher=Siebel Verlag| language=German| isbn=978-3-88180-665-7| year=2007| page=36}} 4. ^in air RJH66 5. ^1 The Russian VLF time-signal stations, “Beta”, by Trond Jacobsen, with detailed transmission format information. 6. ^Meinberg radio clock glossary: R, see entries for RAB99, RJH69, RJH77, RJH86 and RJH90 7. ^Nils Schiffhauer's medium/long-wave signa samples. Particularly see the (frequency-shifted) transmission spectrum. Horizontal divisions at 200 Hz show 100 Hz between frequencies.. Further reading{{refbegin}}
6 : Time signal radio stations|Science and technology in the Soviet Union|Soviet inventions|Communications in the Soviet Union|Soviet Navy|Russian Navy |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 随便看 |
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。