Jo Jennings’ History

Jo Emmett Jennings was born and raised in the San Jose area in an agricultural family. At the age of 12, he built his first radio receiver using an oatmeal container as a form for the coil and a "catwhisker" detector. He was issued a Ham Ticket (W6EGV) in 1929 and continued his active interest in radio transmission. Jo pioneered many developments in the field of radio transmission through his ham radio interest. During the period of 1931-32 he was hired as the night and Sunday operator of radio station KQW, which was one of the first commercial radio stations in America. He was also an accomplished musician and had his own dance band, "The Horned Toads," which helped to finance his college education.

Following college, he joined the Eitel-McCullough Company (EIMAC) and worked in the development of vacuum tubes. In 1940 when he struck out on his own and Jennings Radio Manufacturing Corporation was formed with operations beginning in a building (empty chicken coops) on the family farm property in San Jose. In 1942 a partnership with Fred Gillmeister, Calvin Townsend, and Arthur Neild was formed. Mr. Gillmeister later left the company and Mr. Townsend became President of the corporation with Jo as Vice President. "Cal" had the business expertise and Jo was the lead technical innovator and developer. Mr. K. V. King later joined as a silent partner and this group ran the company until its sale to ITT in 1961.

The first products Jo developed were the Vacuum dielectric Fixed Capacitors with glass envelopes. The Variable version was soon to follow. The first products were pumped with oil diffusion pumps, which used Triton motor oil since good vacuum oil was in limited supply due to the war effort (WW II). Jo could not obtain thin sheet nickel to fabricate the capacitor plates so he used the sheet metal from the Triton oil cans and produced his first successful capacitors. The first government contract hinged on a company that had more than three to four people working in chicken coops, so a 30' x 80' building was constructed and with the help of the Hallicrafters company, the first contract was issued. Fortunately, a convoy was to be passing through San Jose with a communications vehicle on display when Jo needed full field testing of his "Triton oil can" capacitor. He was able to have the capacitor successfully tested in the rig and got an allocation of nickel to build more products for test at the Signal Corps Labs.

Within a few years Jo had surrounded himself with a group of about 20 highly skilled key employees who were necessary for the rapid growth of the company at that time.

Jo kept his active interest in any form of radio transmission and developed numerous ham related product ideas through the years. Jennings marketed vacuum dielectric relays and high current interrupters in the 1950's to broaden the product offering.

Jo and Cal Townsend (his major partner) sold the company to ITT in 1961 to bring greater financial stability to the growing business of multi-million dollar proportions and a few hundred employees. Jo and Cal left the company in 1966 having set it in motion to continue successfully for many decades.