Russian National Time Scale Long-Term Stability

The Institute of Metrology for Time and Space NPO VNIIFTRI generates the National Time Scale (NTS) of Russia - one of the most stable time scales in the world. Its striking feature is that it is based on a free ensemble of H-masers only. During last two years the estimations of NTS longterm stability based only on H-masers intercomparison data gives a flicker floor of about (2 approx. 3) x lo-15 for averaging times from 1 day to 1 month. Perhaps the most significant feature for a time laboratory is an extremely low possible frequency drift - it is too difficult to estimate it reliably. The other estimations, free from possible inside the ensemble correlation phenomena, are available basing on the time comparison of NTS relative to the stable enough time scale of outer laboratories. The data on NTS comparison relative to time scale of secondary time and frequency standards at Golitzino and Irkutsk in Russia and relative to NIST, PTB and USNO using GLONASS and GPS time transfer links gives stability estimations which are close to that based on H-maser intercomparisons.