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