Complex sentence: Until the end of the 1990ies, the station was controlled by the Naval Communications Station, Stockton, CA, today it is operated by Rome Research Corporation on a contract basis for the Department of Defense.
Split into simpler sentences: Until the end of the 1990s, the station was controlled by the Naval Communications Station, Stockton, California. It is currently operated by Rome Research Corporation on a contract basis for the Department of Defense.