the San Francisco Bay area, employing vacuum-tube transmitters, began making regular entertainment broadcasts, most prominently the "California Theater" station, 6XC, set up by Lee de Forest, which began daily service around April 1920. After the war Herrold needed to become familiar with vacuum-tube equipment before he could return to the air. Although some of his co-workers later reported that he resumed regular broadcasts as early as 1919, the oldest documented report of his resumption of broadcasting, presumably over 6XF, dates to early May 1921, with the announcement that the school was inaugurating a Monday and Thursday night schedule consisting of records supplied by "J. A. Kerwin of 84 East Santa Clara street, dealer in phonographs". KQW (1921–1949) Effective December 1, 1921, the Department of Commerce issued a regulation that stations making broadcasts intended for the general public now had to hold a Limited Commercial license specifying operation on a wavelength of 360 or 485 meters, and, on December 9, 1921, a broadcasting station authorization with the randomly assigned call letters of KQW was issued in Herrold's name. This license specified operation on the common "entertainment" wavelength of 360 meters (833 kHz), so KQW initially broadcast only during the hours assigned to it under a time-sharing agreement made with the other local broadcasting stations. Classifying stations according to when they first received a broadcasting authorization under the provisions of the December 1, 1921, regulations, KQW was tied for 6th in the state of California and 16th in the United States. It is the eighth oldest surviving radio station in the United States and tied for 2nd oldest in California, one day behind KWG in Stockton, and tied with KNX in Los Angeles. It is also the oldest in the Bay Area; the next-oldest, KMKY in Oakland, was licensed as KLS on March 10, 1922. Operation of KQW was financed by the sale of radio equipment by the Herrold Radio Laboratory, but by 1925 the costs had grown. The station was transferred to the First Baptist Church of San Jose, with Herrold kept on as program director. In 1926, station manager Fred J. Hart bought KQW's license and facilities, eventually buying the station itself in 1930. From 1937 to 1941, KQW served as the San Jose network affiliate of the Don Lee Broadcasting System. During this time its owner was Julius Brunton & Sons, and the station's operations were co-located with KJBS