If you receive HD Net (HiDef), they broadcast a set of HD test patterns for 10 minutes every Tuesday morning at 8am ET.
Also, sometimes HBO broadcasts test patterns, but they're never announced in any schedules that I've seen.
If you receive your local channels via DirecTV, check them after "signoff" time and they may be broadcasting a test patter.
Also, sometimes HBO broadcasts test patterns, but they're never announced in any schedules that I've seen.
If you receive your local channels via DirecTV, check them after "signoff" time and they may be broadcasting a test patter.