Here's some of the "back story": Super 15 KBLA tried to compete with KHJ, KRLA and KFWB with a Top 40 format circa 1966-67, and it was a good station - good DJs more befitting a higher power station, and some alternative programming. But the signal was so poor that it reportedly went null in the station's parking lot. Growing up in nearby Tujunga - less than 10 miles away, I could get KBLA in the daytime - but at night, forget it.
After a couple of years, it flipped to country as KBBQ ("K-Barbeque" if you can believe that), and did rather well for a few years. I moved out of the LA area, but I know that some years later, 1500 became the original KROQ, which didn't acquire 106.7 FM until a couple of years later, but I am less familiar with that part of the story.
Filling in some of the gaps from what Llew wrote:
KBLA actually was a daytimer at 1490 on the dial with 250 watts from June of 1952 until February, 1965, when it moved to 1500 AM with 10,000 watts daytime and 1,000 watts directional at night to protect KSTP, Minneapolis, which had protested the move.
But before the move, on the old frequency, with the old power, KBLA moved to Top 40 in August of '64 (apart from mornings, where a Lawrence Welk radio show carried over from the old block programming) and a jock lineup that included local legend Huggy Boy, as well as Rosko, Tom Clay, Jim Wood and a kid name Vic Gee, who would grow up to become Jim Carson (KGB, KFRC, K-100, KRTH and others).
The switch was flipped on the new transmitter on February 12, 1965---two and a half months
before KHJ went Boss Radio.
But then, in July, GM Mel Leeds shot the station in the foot, firing all the jocks except for Vic Gee and automating.
Owner George Cameron (who also owned KDES in Palm Springs, as well as The Palm Springs Desert Sun newspaper and had oil investments dating back to the late 1930s) figured it out by December of '65, fired Leeds, kept Vic and hired Roger Christian and Dave Diamond (who'd both been blown out of KHJ in its first six months) Harry Newman from New Jersey, William F. Williams from KLIV, San Jose and Humble Harve from WIBG, Philadelphia.
But there was still the signal. 10kw at 1500 AM was adequate (barely) to cover the L.A. metro in 1965 (remember, Riverside-San Bernardino, Orange County and Ventura County were their own separate markets at the time), but that night signal was going nowhere. And night signal is critical, because for part of the year, part of your morning drive and part of your afternoon drive is on night pattern.
So, despite some solid talent, it wasn't working. KHJ stole Harve in February of '67. That blew a hole in more than KBLA's air talent---Harve was Program Director. Cameron hired Bill Ward from KBOX in Dallas, where he had changed the format from Top 40 to Country just a month before
On June 16, 1967, about a year and a half after George Cameron re-staffed the station, Ward did the same to KBLA. Dave Diamond, who arguably was doing underground/freeform/album rock before Tom Donahue, was the last jock and all three hours, unscoped, of that show exist.
At midnight, they went Country as KBBQ (the format change, which had a couple of hiccups---and is also exactly how Ward kicked off the Country format at KBOX---with Buck Owens' "I've Got A Tiger By The Tail", is also part of the Diamond aircheck). Harry Newman and Vic Gee stayed on.
The approach during the Country run was actually pretty savvy. Cameron understood the signal limitations and marketed KBBQ to San Fernando Valley listeners, not unlike KGIL. At the time, there were one-and-a-half million people living in the Valley, so there was an ad base. And since there were two other radio stations doing Country at the time (KGBS, a daytimer at 1020 with an FM at 97.1 and KFOX at 1280 in Long Beach)---neither of whom could blanket the entire metro 24-7, KBBQ had Country fans in the SFV largely to themselves. A Billboard story from June of 1968 says KBBQ and KFOX formed a sales alliance, allowing advertisers to buy time on both stations.
Basically, it was working.
Then, George Cameron died of a heart attack on May 22, 1970. The family (and Ward) kept things running smoothly (Ward was GM and PD by this point) for a while, but Metromedia stole Ward away to program KLAC in 1971. He'd be GM there within a year.
The Cameron estate sold 1500 to Gary Bookasta's Burbank Broadcasting for $2.2 million in 1972. Bookasta made a big splash, hiring name personalities in L.A. (Charlie Tuna, Sam Riddle, Jay Stevens, Johnnie Darin, Jim Wood, Jimmy Rabbitt) and making a point of letting the world know he was paying them all equally---$100,000 a year. He planned a six-hour concert at the Los Angeles Coliseum for Thanksgiving weekend, promising Sly and the Family Stone, Chuck Berry, Stevie Wonder, the Bee Gees, the Eagles and more in a six-hour concert benefitting the Southern California council of free clinics. Tickets were $3.00. 32,848 fans showed up...which meant a gross of $98,544. Trouble is, Bookasta borrowed $200,000 to promote it.
Paychecks started bouncing in 1973 and jocks headed for the exits. First Jay Stevens, then Charlie Tuna. Bookasta offered Rabbitt a Porsche to stay. Rabbitt said yes, only to find out that a Porsche won't pay the rent or buy you food. An FCC report later found that KROQ was $800,000 in debt in October of 1973---13 months after launch---and had defaulted on its principal loan from Bank of America.
At least $150,000 of that debt was to concert promoter Ken Roberts, who ultimately would gain control of the station and it was on his watch that the KROQ of legend was born.
In researching the facts for this post, I ran across an FCC filing that details the twisted tale---including some shennanigans under which, after buying the station from the Cameron Estate, Burbank Broadcasting owned an entity called George E. Cameron, Jr. Communications (GECC), which was supposedly responsible for the license, but abdicated that responsibility in spectacular fashion (they're described as "investors" and "spectators").
https://books.google.com/books?id=8N0kX81DVgQC&pg=PA877&lpg=PA877&dq=KROQ+1972+concert&source=bl&ots=_grrggcbUp&sig=ACfU3U06YoTtZj9PsVp9M4e81XUWO7Q6yg&hl=en&sa=X&ved=2ahUKEwi93tTu0snnAhXsN30KHbQRCaUQ6AEwB3oECAoQAQ#v=onepage&q=KROQ%201972%20concert&f=false
You'll need to scroll up about eight pages to get to the beginning from where the link lands you.
It's too early in the morning. If someone else can do Cliff's Notes on that whole mess, I'll be thrilled to read it.