RBU is a time code radio station located in Moscow (56°44′00″N 37°39′48″E / 56.73333°N 37.66333°E). It transmits a continuous 10 kW time code on 66⅔ kHz. This is commonly written as 66.66 or 66.666 kHz, but is actually 200/3 = 66.6̅ kHz. Until 2008, the transmitter site was near Kupavna 55°44′04″N 38°9′0″E / 55.73444°N 38.15000°E and used as antenna three T-antennas spun between three 150 metres tall grounded masts. In 2008, it has been transferred to the Taldom transmitter at 56°44′00″N 37°39′48″E / 56.73333°N 37.66333°E.