4:30 PM -- Oof! Ovum RHK Inc. says that mobile operator's capital expenditures in North America fell 18 percent in the third quarter even as wireless revenues grew nearly 10 percent year-on-year.

Mobile capex for the quarter was $4.7 billion, down 18.2 percent year-on-year, even as revenues grew 9.6 percent to $37.9 billion. Wireless revenues are quickly catching wireline revenues, which hit $43.8 billion over the summer.

So why the rapid drop in capex? Ovum says that the overall decline in capital expenditure in the U.S. was due in part to the problems at Sprint Corp. (NYSE: S). (See Sprint Stumbles Again.)

"Mobile capex hit a real pothole, led by Sprint Nextel," says John Lively, VP of forecasting at Ovum RHK. "With mobile capital intensity at a seven-year low, however, there is room for a rebound in 4Q07."

Ericsson AB (Nasdaq: ERIC), Motorola Inc. (NYSE: MOT), Nortel Networks Ltd. and others must be hoping that's the case.

— Dan Jones, Site Editor, Unstrung