Beta (time signal)

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.

Each transmitter has 1 or 2 scheduled sessions per day lasting 31–41 minutes, depending on transmitter, total 8 sessions in 24 hours. Beginning on the hour is 15–20 minutes of 25.0 kHz, including morse code station identification and time code. This is followed by 3- or 4-minute intervals of 25.1, 25.5, 23.0 and 20.5 kHz of unmodulated carrier precisely phase-locked to UTC(SU) time scale. No time code is sent during the last quarter of an hour.[2]

The Beta network

Beta consists of the following transmitters:[3][2]

Callsign Transmitter Location 20.5 kHz 23.0 kHz 25.0 kHz 25.1 kHz 25.5 kHz Coordinates
RJH63 Krasnodar x x x x x 44°46′25″N 39°32′50″E / 44.773537°N 39.547241°E / 44.773537; 39.547241 (RJH63)
RJH69 Vileyka VLF transmitter near Molodechno (Belarus) x x x x x 54°27′44″N 26°46′09″E / 54.462356°N 26.769218°E / 54.462356; 26.769218 (RJH69)
RJH77 Archangelsk x x x x x 64°21′38″N 41°34′07″E / 64.360491°N 41.568489°E / 64.360491; 41.568489 (RJH77)
RJH86[4] Bishkek (Kyrgyzstan) x x x x x 43°02′22″N 73°36′45″E / 43.039444°N 73.6125°E / 43.039444; 73.6125 (RJH86)
RJH90 Nizhny Novgorod (former German Goliath transmitter) x x x x x 56°10′19″N 43°55′54″E / 56.171945°N 43.931667°E / 56.171945; 43.931667 (RJH90)
RAB99 Khabarovsk x x x x x 48°29′08″N 134°49′24″E / 48.485550°N 134.823330°E / 48.485550; 134.823330 (RAB99)
Beta (time signal) is located in Russia
RJH63
RJH63
RJH69
RJH77
RJH77
RJH86
RJH86
RJH90
RJH90
RAB99
RAB99

Frequency usage

The 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.)

Beta hourly transmission schedule[5]
Frequency Minutes Signal
Start Duration
25.0 kHz :00 1 Transmitter tune-up, low-power unmodulated carrier
:01 5 Unmodulated carrier
:06 1 Morse code call sign, on-off keying
:07 3 Unmodulated carrier
:10 3 On-off modulated with 40 Hz square wave
:13 9 Time code, on-off modulation
:22 3 On-off modulated with 40 Hz square wave
25.1 kHz :25 1 Transmitter tune-up, low-power unmodulated carrier
:26 4 Unmodulated carrier
25.5 kHz :30 1 Transmitter tune-up, low-power unmodulated carrier
:31 4 Unmodulated carrier
23.0 kHz :35 1 Transmitter tune-up, low-power unmodulated carrier
:36 5 Unmodulated carrier
20.5 kHz :41 1 Transmitter tune-up, low-power unmodulated carrier
:42 5 Unmodulated carrier
Off :47 Transmission ends

The time code consists of a series of carrier pulses:[6]

  • Each 100 ms, a 25 ms burst of carrier is transmitted
  • Each second, a 100 ms burst of carrier is transmitted
  • Each 10 s, a 1 s burst of carrier is transmitted
  • Each minute, a 10 s burst of carrier is transmitted

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:

RJH63 and RAB99 hourly transmission schedule[5]
Frequency Minutes Signal
Start Duration
25.0 kHz :00 1 Transmitter tune-up, low-power unmodulated carrier
:01 5 Unmodulated carrier
:06 1 Morse code call sign, on-off keying
:07 2 Unmodulated carrier
:09 2 On-off modulated with 40 Hz square wave
:11 9 Time code, on-off modulation
25.1 kHz :20 2 Transmitter tune-up, low-power unmodulated carrier
:22 1 Unmodulated carrier
25.5 kHz :23 1 Transmitter tune-up, low-power unmodulated carrier
:24 2 Unmodulated carrier
23.0 kHz :26 1 Transmitter tune-up, low-power unmodulated carrier
:27 4 Unmodulated carrier
20.5 kHz :31 1 Transmitter tune-up, low-power unmodulated carrier
:32 4 Unmodulated carrier
:36 4 (RJH63 only) Digital data, ±50 Hz frequency-shift keying, 50 baud[7]
Off :40 Transmission ends

See also

References

  1. ^ C3 Systems of the CIS Navy Archived October 5, 2011, at the Wayback Machine
  2. ^ a b c Эталонные сигналы частоты и времени [Standard Time and Frequency Signals] (PDF) (in Russian), retrieved 2020-05-10. Official signal specification.
  3. ^ Marten, Michael (2007). Spezialfrequenzliste 2007/08, band 2 (in German). Siebel Verlag. p. 36. ISBN 978-3-88180-665-7.
  4. ^ in air RJH66
  5. ^ a b 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