From The Greatest Minor League: A History of the Pacific Coast League, 1903-1957, by Dennis Snelling (McFarland, 2011), Kindle Loc. 2224-2241:
Radio was becoming wildly popular, and in 1927 two important developments accelerated growth in the fledgling industry. First, radio manufacturers reached agreement with the Radio Corporation of America (RCA) to use company patents that were essential in mass production of radio sets. Second was the development of the alternating current radio tube, which made it possible to manufacture radios that could be plugged into a standard electrical outlet.
Mass broadcasting to the general public was on the horizon and sports were to be a major beneficiary of this new technology. Baseball had been broadcast on radio since 1921, and the New York Yankees had aired the World Series for several years, more or less in the same play-by-play fashion as today. However, most baseball coverage consisted of a simple recitation of wire accounts sent by telegraph to the local station, providing only the actual details of the game without commentary.
KHJ in Los Angeles broadcast play-by-play results of the World Series in 1925 to great fanfare, relaying results from three thousand miles away almost as they happened. By 1927 KPO radio in San Francisco was using a direct line from Recreation Park to provide play-by-play details of every game. In Oakland and Seattle, game accounts and scores were provided nearly every day except Sunday. William Wrigley, who had a direct telegraph wire into his home on Catalina Island so he could keep abreast of his Chicago Cubs, took notice of radio’s potential to promote the last-place Los Angeles Angels. Hoping broadcasts would drum up interest in an otherwise uninteresting team, Wrigley announced that KHJ would cover the Angels every day.
There would be lively debate about radio in the PCL [= Pacific Coast League] over the next few seasons – Bill Lane for one remained there was no turning back. At the league meeting following the 1928 season, a resolution was defeated that would have banned radio from the ballparks. Though yet in its infancy, radio would soon become as inseparable from baseball as newspapers were.
Ironically, at the same time radio was becoming established, a new invention was being developed on the second floor of a warehouse at 202 Green Street in San Francisco, near Telegraph Hill. This new all-electric technology would further revolutionize broadcasting and the world of sports. In January 1927, Philo T. Farnsworth, the twenty-year-old son of an Idaho farmer, met with Crocker Bank vice president James J. Fagan and pitched his idea. Fagan, whose son would later own the San Francisco Seals, was able to convince W.W. Crocker, president of the bank, to invest in it. Nine months later, Farnsworth completed the first successful demonstration of his new technology at the Green Street warehouse. On that day in San Francisco, modern television was born.