KPEN 101.3 FM Atherton, CA | Bay Area Radio Museum & Hall of Fame

Launched in 1957, KPEN would morph into one of the nation’s most influential FM radio stations.

The station began with the realization by a couple of Stanford students, James Gabbert and Gary Gielow, that FM frequencies were available. The two were involved with the Stanford campus station KZSU and thought having their own commercial station might be a fun thing to do after graduation.

KPEN cofounder John Wickett in 1958 Peninsula Times Tribune photo — John Wickett (Peninsula Times Tribune, 1958)

Gabbert and Gielow each borrowed $3,000, each pledged $2,000 worth of labor, and when young Peninsula real estate investor John Wickett tossed in $5,000, the two 21-year-olds were in the radio business. They called their new company Peninsula FM. The 101.3 FM frequency was available because KLX had abandoned the FM dial several years earlier, one of many “first-wave” FM broadcasters to give up before the FM band gained traction.

They made their first broadcast on October 27, 1957. The transmitter sat atop King’s Mountain, near Skyline Boulevard in San Mateo County. The studio and transmitter were housed in an old hut that had been trucked to the mountaintop.

Gielow would recall a few years later, “We had to succeed quickly because we’d forgotten about operating capital. We had nothing left to eat on. While Jim manned the station, I went out and sold.”

What Gielow was selling was a station unlike any other in the country. They programmed what they wanted to hear, taking advantage of a boom in high-fidelity sound recordings and the new stereo FM broadcast technology to deliver a sound that hadn’t been heard before. KPEN was the first multiplex stereophonic FM broadcaster in California.

Four years later, stereo FM was still a bit of a novelty, but KPEN was all-in. Peninsula Times-Tribune columnist George Willey would write, prophetically, in 1961: “KPEN is the best thing to ever happen to expand FM in the Bay Area and may well turn out to be the best thing to ever happened to multiplex in the United States.”

On August 25, 1959, KPEN’s power was increased to 35,000 watts from its new transmitter site on San Bruno Mountain, making its high-fidelity monaural signal available to a greater number of audio enthusiasts around the Bay Area. The station celebrated the move and its second anniversary with a large ad in the San Francisco Examiner.

By then, the station had survived a kerfuffle over its city of license. The Town of Atherton had an ordinance banning business activities within the town limits. Mayor Henry Kuechler dismayed of hearing “KPEN, Atherton” during station ID’s and huffed that the town should “lower the boom” and take the fledgling station to court. Nothing ever came of the threat.

One of the most popular programs on KPEN was James Gabbert’s nightly “Excursions In Sound,” which featured a broad variety of hi-fi recordings — music, comedy, sound effects — selected by the host in order to challenge the “fi” of the listener’s audio equipment. Included were submissions by the listeners themselves of sounds they recorded on their own machines.

KPEN became an early and enthusiastic stereo broadcaster, launching multiplex stereo programming in July 1961. Gabbert’s “Excursions In Sound” became “Excursions In Stereo” and now the fun really began: trains rumbling from left to right, ping-pong matches, and more.

In December 1968, KPEN changed its call letters to KIOI and began calling itself “K-101”, a legendary marketing decision that took advantage of its place on the FM dial.