Abstract
Design and performance of the NRC 2.1 meter cesium beam frequency standard are discussed. Construction of the beam tube, microwave cavity, and the electronics providing the beam excitation signal are outlined. Sources of error are discussed, and a value of 1.9 × 10-11 is estimated as the upper limit. Comparisons via VLF transmissions over a 9 month period with similar standards at NPL, NBS, and LSRH are described in detail. Closest agreement exists between NRC and NBS with WWVB as the commonly measured signal. Maximum, mean, and r.m.s. deviations over a 7 month period were 18, 1.1 and 6.6 × 10-12 for 15 day averages.