Welte-Mignon Corporation [Welte Organ Co.]
1927

KPO was a radio station that started small but was destined to become a giant. It all began in 1921, when Joe Martineau completed his tour of duty with the Navy and came back to San Francisco. He had done a lot of radio work in the Navy, and wanted to continue with it. He visited the Hale Brothers — Francis, Marshall and Reuben — owners of Hale Brothers Department Store, one of San Francisco’s largest.

Altogether, $60,000 was spent on refurbishing the station, quite an elaborate radio investment in 1923. The Western Electric 500-watt transmitter was mounted with its associated amplifiers and other equipment in what had been the original KPO studio, and a small room next door was converted to house the generators.

A new and larger studio was constructed adjacent to these rooms, and a pipe organ was installed. Two 125-foot steel towers were erected on the roof of the building, and a four-wire T-type antenna was strung between them. The new super-powered KPO was on the air.
-- information from The History of KPO Radio, San Francisco, By John F. Schneider (website)