The picture will bob up and down seasickwise if your lead in wire gets loose and flaps against some metal such as the TV mast or rain guttering. The cure, snug down with new standoffs till the wire is tight and won’t move in the wind.
The TV screen will receive excessive interference if youhave a simple type antenna in a bad signal area. The weak aerial permits all of the unwanted signal to enter the TV along with the desired signal.
The best way to reduce interference is install a stacked, motorized, high gain, highly directional antenna, in place of the simpler types.
Loss of Fine Detail
Loss of fine detail is actually ghost images almost but not quite correctly on top of normal signal. You lose the picture detail because of incorrect lead in wire installation. The lead in wire is too near or mounted right on top of some metal causing impedance bumps or standing waves. The cure, reroute such lead in wire and liberally use standoffs at any possible impedance bump or area.
There is such a thing as the TV signal being too strong. That occurs by use of high gain antenna systems in strong signal areas. For instance, the faraway stations come in excellently but the nearby stations are too contrasty and have the bends. The cure is to reduce or attenuate the local stations’ strength. This is done by means of a “pad” as illustrated. The pad is switched in for the local stations and switched out for distant TV viewing.