Electromagnetic compatibility problem with an hairdryer
Here is the explanation, TV or other communication signal works on Radio Waves, which are nothing but varying electric field and magnetic field. The hair drier has a motor in it, which has brushes to make electrical contact with the armature. When the motor rotates it created a varying magnetic field and electrical field across the brushes that can be see in the form of spark. This is called the back emf, in order to suppress EM interference such devices comes with a small capacitor in parallel with the motor. you hair drier motor might not have that. Also, the varying inductance interfere with the line voltage that may also cause EMinterference. 
other possibility could be, Your TV signal may be weak hence getting impacted with the EM interference.

I used to play with elf made electromagnet bell made with just a single relay during childhood when i observed, this effect.