Not moving the reason for interruption in radio activity (6)
I believe the answer is:
static
'not moving' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for static that I've seen before include "stable" , "Unmoving like kind of electricity" , "Stationary" , "Still, unchanging" , "Not active, immobile" .)