Thoughts on the KRTH / KATY interference
Docket 80-90 was controversial at the time, with many engineers referring to it as “the AM-ization of FM.” The premise was that modern receivers were better than the ones available when the FM rules were drawn up.
Grandfathered super powers are only granted protection to their “on paper” class B contours. KRTH does not enjoy any protection in the inland empire, even though it has a signal that is useable there. Thus KATY went on the air with degraded interference protection from KRTH because of KRTH’s grandfathered status.
I think the claim that KATY causes a degradation of KRTH’s LA coverage is a stretch. They probably do bother them in the inland empire, but that is beyond KRTH’s “on paper” class B contour. I suppose there could be pockets of interference where KRTH’s signal has terrain blockage and KATY doesn’t, but I would expect those areas to be few, and to have poor KRTH coverage even without KATY.
However, HD radio wasn’t even a gleam in anyone’s eye at the time 80-90came along. With IBOC “In Band Off Channel” operation, the situation gets worse very quickly. One thing everyone seems to forget is that the -20 db of IBOC power is 20 db below the grandfathered power level, not the “on paper” class B power level.
This seems to be a case of two bad decisions the FCC made (IBOC and 80-90) colliding big time in a crowded major market. This “give them anything they want” approach that started with the Fowler commission in the Reagan administration is finally coming home to roost in a big way. I doubt seriously that the FCC would ever take responsibility for this mess, as politicians will never admit that they made a mistake. It will be interesting to see how this plays out. I think the real winners here will be the lawyers.
Chris Hays