The TV reception and the picture quality have suddenly deteriorated?
The solution is very simple if the TV reception and the picture quality suddenly deteriorate.
1. If possible, test the picture on the same connection with another TV set.
2. Check the antenna cable for any kinks or other damage.
3. In the case of satellite dishes, these should possibly be realigned.
It is not that uncommon for the antenna (coaxial) cable to be damaged and if, for example, many cell phones or other radio devices (WLAN, telephone, ...) have been added in the vicinity, picture interference and poor reception can subsequently occur comes, even if the cable has been damaged for years.