RWM
Coordinates: 55°43′36.73″N 38°12′29.39″E / 55.7268694°N 38.2081639°E RWM is the callsign of a high frequency (shortwave) standard frequency and time signal radio station in Moscow, Russia. RWM transmits on 4996 kHz with 5 kW and on 9996 and 14996 kHz with 8 kW.
The frequencies are very close to those of WWV, and WWVH. 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 (CW). Between 0 and 8 minutes past the hour, RWM transmits a straight unmodulated carrier wave. At 9 minutes past, RWM identifies itself in Morse code. Between 10 and 20 minutes past the hour, RWM transmits a pulse of carrier every second, with the difference between UT1 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.
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:
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