Hydrogen maser performance at the United States Naval Observatory and the Naval Research Laboratory

The United States Naval Observatory (USNO) has been using hydrogen masers for over six years as part of the USNO master clock. The Naval Research Laboratory (NRL) has also been using maser references as part of the NRL clock testing facility since September 1985. The masers discussed include the Smithsonian Astrophysical Observatory VLG-11, VLG-12, and masers from the Sigma Tau Standards Corporation. The authors describe the operation of the masers at USNO and NRL, including stability, aging rates, and reliability.<
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