A phenomenon colloquially understood as a “hot air sandwich” squeezed out an FM frequency hosted by KCBX.
Changes in atmospheric conditions due to climate change forced the radio news station to end service on 89.5 FM KSBX after almost 40 years of cultivating listenership in Santa Barbara County. KCBX also serves San Luis Obispo and southern Monterey counties.
“KCBX considers Santa Barbara an integral part of our listenership, and we have no plans to reduce or limit news coverage or reporting on local Santa Barbara events and happenings,” General Manager Frank Lanzone said in a press release dated Dec. 19. “As a Central Coast public radio station, we consider Santa Barbara residents part of our KCBX family.”
Called tropospheric ducting, the natural process created by warmer waters allows FM frequencies to cover larger distances over the ocean. WHRO Public Media explained it as a layer of warm air getting trapped between two layers of cool air—one close to the water surface, and the second close to outer space. This “hot air sandwich” makes the radio signal travel farther than usual.
“As a result, broadcasts on a frequency many miles away are able to reach new coastlines and interfere with the same frequency that would previously be shielded from that interference based on distance alone,” the KCBX press release said.
But the signal is in jeopardy when it gets to the boundary between warm and cool air, causing it to bend. The signal warps again when it travels below to the next boundary of warm and cool air.
“The KSBX frequency at 89.5 FM is an unfortunate victim of this phenomenon, being increasingly overrun by a station using the same frequency 200 miles away, creating an unintentional problem that that the other station cannot fix,” the press release stated.
Lanzone told New Times that the Federal Communications Commission doesn’t regulate environmentally caused interferences. The radio station encouraged Santa Barbara listeners to tune in using other forms of media like its website kcbx.org, the NPR mobile app, and the Apple Music app.
“Some areas on the outskirts of Santa Barbara, including most of the city of Goleta, will still be able to listen on the KCBX 90.9 FM signal,” the KCBX statement read. Δ
This article appears in Dec 22, 2022 – Jan 1, 2023.