The red line going across the screen is the device notifying you that it is trying to receive a signal. The antennas may have gotten damaged over time and the device is not able to pick up a signal. I had an older watchman like this several years ago, and the red line is the device seeking reception and not finding a strong signal.

*edit* Forgot to mention that the US has discontinued analog television signals since 2009, so you most likely will never again receive reception.