Adjacent FM in SF

[MR5229]

Can anyone explain why 98.9 KSOL and 99.1 KSQL are spaced as adjacent channels? I can't think of any other San Francisco FMs that have an adjacent channel in San Jose. It seems strange to have those 2 stations so close together on the FM dial. It doesn't seem to matter though about those 2 stations interfering with each other, as KSQL is a simulcast of the San Francisco station.

 

[DeadAudicy]

I think you answered your own question.

 

[DaveBayArea]

It has to do with history and grandfathering. A long time ago, the FCC only required that FM stations don't interfere with each other. There were no mileage separation restrictions. 99.1 used to be KSCO-FM in Santa Cruz, transmitting from a low-elevation tower with significant shielding from the Bay Area due to the Santa Cruz mountains. Sometime around 1987 (not sure of the exact timetable, but close) that transmitter was moved to Loma Prieta. The only requirement was that the "predicted" contours at the higher elevation match the previous short-spaced contours when the transmitter was at negative HAAT. So the Loma Prieta transmitter was installed with a directional antenna to achieve this.

I can't remember, but I think the ERP on 99.1 towards San Francisco is quite low - like on the order of 160 watts. But it's 4000 feet above sea level. When 99.1 first moved to Loma they were not co-owned. 99.1 was KLRS, a pre-NAC NewAge station, and 98.9 was KKCY, with an eclectic format. I had many friends in San Jose who were quite upset at the loss of KKCY when KLRS signed on from Loma Prieta. Both stations went through a couple of format changes & owners, until Viacom bought them both & they became "double 99". From that point on, the two have been co-owned and simulcasted, so the interference issues are less significant.

Interestingly enough, the old rules regarding short-spacing and interference are still in place in the non-comm band. The other 1st adjacent spacing in the SF Bay Area is KALW and KKUP (91.5 and 91.7). KKUP is on the exact same tower as KSQL and KALW is on Twin Peaks, less than a mile away from KSOL.

Dave B.

 

[LKellerIII]

Great explanation, even for those of us who are technologically challenged...though I'll admit I don't know what "negative HAAT" is.

One historical correction though: Since Viacom, the 2 frequencies have been co-owned, but following Viacom's "Double 99" and "Star FM" simulcasts (early 90s, if I remember correctly), the company that owned Wild 107 (pre-Clear Channel) purchased 98.9 and 99.1. They moved the KSOL call letters to 98.9 for a Classic Soul format. They then used 99.1 to simulcast 107.7. This lasted until the sale to Clear Channel...a couple of years, perhaps.

My kid (now grown) stuck a "Wild 107...now on 99.1" bumper sticker on the desk in her room. The desk now holds tools in my garage, but the sticker is still there.

 

[DaveBayArea]

You're right. I forgot about the Wild simulcast period. Oh - and HAAT means "Height Above Average Terrain". Part of the formula the FCC uses to predict coverage. Negative numbers are rare, but not unheard of.

Dave B.

 

[kenrayc]

Another example is when KSJO had 3 stations 92.3 San Jose, 92.1 Walnut Creek and 92.7 in San Francisco.

 

[jprg]

I worked at KLRS 99.1 in 1988 and me and the CE Bill Brooks went up to Loma Prieta a few times and he showed me how the directional antenna worked. KLRS had a killer signal south towards King City. The San Jose coverage was "okay" but there were a lot of drop outs there. By the way 99.1 broadcasts at 1100 watts at least they did when I was there in 1988. Great view of the Santa Clara Valley and Monterey Bay

 

[Madmansam]

the company that owned Wild 107 (pre-Clear Channel) purchased 98.9 and 99.1.

I think that company was Crescent Communications, though I might be wrong.

 

[deano_61]

Another example is when KSJO had 3 stations 92.3 San Jose, 92.1 Walnut Creek and 92.7 in San Francisco.

Let's not forget 92.7 as well in Marina (Monterey-Salinas). The calls were KMJO from KRQC