21. WSKY-DT started broadcasting a test pattern on November 24, 2007. 22. At 5 : 59PM, the test pattern gave way to a solid black screen. 23. Clogged nozzles can be detected by printing a standard test pattern on the page. 24. About 24 hours after the attack, the program was replaced with a test pattern . 25. It's the night that networks other than NBC would just as well run test patterns . 26. Monoscopes were used beginning in the 1950s to generate TV test patterns and station logos. 27. The station eventually began broadcasting a test pattern on 19 June 1999 on UHF 41. 28. However, functional test patterns don't discover common fabrication faults. 29. By September 4, 2009, it was broadcasting a color test pattern with its call sign. 30. Since then, Simpson's face has shown up on TV more often than a test pattern .
