HP 5060A Cesium Beam Frequency Standard
The U.S. standard was moved from the East coast to Colorado and was more a frequency standard than a clock. 1964 - The HP 5060A, a cesium-beam standard instrument, gains worldwide recognition as the "flying clock." International standards for time set by flying the HP 5060A around the world. Accuracy 2E-11, Precision 1E-11, uses 5 MHz Xtal ...