Beginning in 1947, Eimac operated FM radio station KSBR from their plant in San Bruno, California, one of only two FM stations in the United States to test the new Rangertone tape recorders (adapted from the German Magnetophon recorders). In need of more space, the company moved to San Carlos in 1959. Eimac's San Carlos plant was dedicated on April 16, 1959. By that time, the company had the following subsidiaries: National Electronics, Inc., Geneva, Illinois, and Eitel-McCullough, S.A., Geneva, Switzerland. During the Cold war era, Eimac supplied U.S. military with klystron power tubes and electron power tubes used in the defense communications network, navigation, detection, ranging and fire-control radars.