overall: 7 in x 19 in x 17 1/8 in; 17.78 cm x 48.26 cm x 43.4975 cm
United States: California, Mojave Desert
Precision frequency standards provide crucial reference radio signals for deep space tracking and navigation. This instrument was installed in 1961 at NASA’s Goldstone tracking station in the Mojave Desert, approximately 45 miles from Barstow, California for the earliest Ranger missions exploring the moon. It provided reference radio frequencies between the station and the spacecraft. It became a secondary frequency standard (see strip of tape on object) when rubidium frequency standards, more precise than the quartz standard, were introduced in 1962 for the Mariner missions.
This frequency standard was made by Sulzer Laboratories Inc., Rockville, MD, about 1960. It contains two Model 5A oscillators, serial no. 410 and 482 in a standard electronics rack mount. The output signals are 5 MHz, 1 MHz and 500 kHz. Each oscillator uses the Bliley BG61AH-5, 5-MHz AT-cut resonator.
Peter Sulzer invented the first fully transistorized quartz oscillator. The Model 5A is a commercial standard patterned after the AN/URQ-10 developed for military use.
1. Norton, J., J. Cloeren and P. Sulzer, "Brief History of the Development of Ultra Precise Oscillators for Ground and Space Applications," <i>Proceedings of IEEE 50thFrequency Control Symposium</i> (1996), 47-57.