Fresno-based Pappas Telecasting, a privately-held operator of 30 TV stations including KTNC Channel 42 in San Francisco, filed for Chapter 11 bankruptcy protection on Saturday.

The filing does not apply to the Pappas family’s two radio stations, KTRB-AM 860 San Francisco and KMPH-AM 840 Modesto.

The filing only applies to 13 of the company’s TV stations, including Channel 42, a TuVisión affliate. Of the 13, five are CW affiliates, three are Fox, three are TuVisión and two are CBS.

Pappas cited “the extremely difficult business climate for television stations across the country” in papers filed with the U.S. Bankruptcy Court in Wilmington, Del. The company reported more than $536 million in debt and assets of $460 million.

Pappas blamed the “poor ratings of the CW Network” for some of its problems along with the cost of converting from analog to digital TV.