callsign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigne ...
of a
high frequency
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...
(shortwave) standard frequency and
time signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.
Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, audi ...
radio station in Moscow, Russia. It is controlled by
Russian Television and Radio Broadcasting Network
Russian Television and Radio Broadcasting Network (RTRN) (russian: Российская телевизионная и радиовещательная сеть) is a unitary enterprise created on August 13, 2001, by decree of the president of the ...
. Transmitting frequencies are 4.996 MHz with 5 kW and on 9.996 and 14.996 MHz with 8 kW.
The frequencies are very close to those of WWV, and
WWVH
WWVH is the callsign of the U.S. National Institute of Standards and Technology's shortwave radio time signal station located at the Barking Sands Missile Range, in Kekaha, on the island of Kauai in the state of Hawaii.
WWVH is the Pacific s ...
. Because of this, RWM is very difficult to receive in North America with simple receivers of low selectivity, due to interference from these said stations.
The mode of transmission is N0N and
A1A
State Road A1A (SR A1A) is a major north–south Florida State Road that runs along the Atlantic Ocean, from Key West at the southern tip of Florida, to Fernandina Beach, just south of Georgia on Amelia Island. It is the main road throug ...
(CW). Between 0 and 8 minutes past the hour, RWM transmits a straight unmodulated
carrier wave
In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a ...
. At 9 minutes past, RWM identifies itself in
Morse code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of ...
. Between 10 and 20 minutes past the hour, RWM transmits a pulse of carrier every second, with the difference between
UT1
Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle with ...
and UTC in units of one-fiftieth of a second encoded onto the once-per-second pulses. Between 20 and 30 minutes past the hour, RWM transmits 10 carrier pulses each second. This transmission cycle is repeated every half-hour. -- official signal specification, in russian.
RWM does not transmit the time of day, only standard time intervals.
The 1 Hz pulses begin on the second, and are doubled (a second pulse transmitted from 200–300 ms past the second) to encode DUT1 and dUT1. Using these values, UT1 may be computed as:
: UT1 = UTC + DUT1 × 0.1 s + dUT1 × 0.02 s
DUT1 may vary between −8 and +8. The number of double pulses sent during seconds 1–8 of each minute encode positive values; if DUT1 = +5, then pulses 1 through 5 will be doubled. Doubling pulses 9–16 encodes negative values similarly.
dUT1 varies from −4 to +4. Positive values are encoded by double pulses during seconds 21–24 of each minute. Negative values are encoded during seconds 31–34.
The 10 Hz pulses are widened in a pattern similar to that of the Beta time signal: Most pulses are 20 ms, but ones sent on the second are 40 ms, and ones sent on the minute are 500 ms.
See also
*
Beta (time signal) Beta is a time signal service in the VLF range in Russia, operated by the Russian Navy.TDF time signal