Managers at 760 kHz KFMB-AM say their signal is covered by hash in northern San Diego and throughout Orange County from the digital sidebands of alternate channel 740 kHz KBRT in Avalon on Catalina Island. Radio World’s Leslie Stimson recently filed a report about the battle. KBRT says KFMB has no right to interference protection in these areas since KFMB moved to the alternate channel in 1959 from 540kHz with the proviso of accepting interference outside its metro area of San Diego. KBRT also says it has reduced its IBOC sideband power by 6dB. Southern California has a few alternate channel combos that require stiff NRSC filters and cooperation–think 690 XETRA and 710 KSPN or 1070 KNX and 1090 XEPRS. But KBRT wants the Ibiquity IBOC system on the air, which by definition is “in-band” but not really “on channel”, typically spilling well into alternate channel territory. This one could become a national test case.