What influences digital tv reception or alternatively, why does my tv go on the blink?

For example, when my girlfriend uses her hair dryer upstairs, the tv goes on the blink. also, i swear when a certain type of vehicle goes past our house or parks outside with the motor running, the tv reception breaks up until the so and so drives off. what is that all about then? is it real and if so, why (scientifically) does it happen? alternatively, am i going mad?!
Answer
You might have a ground problem. that would explain the hair dryer. you should have something on your system that looks like the first link bellow. it will ground your outer shielding of the cable from your antenna.as for the car going by thats from reflections. grounding your system properly may reduce this, and thats where i would start, but you may need to get a more directional antenna. the grounding will cost less.