Still a cause of poor reception (6)
I believe the answer is:
static
This clue could be a double definition.
'still a cause' is the first definition.
'static' can be an answer for 'still' (static can mean still or not moving). I'm not sure about the 'a cause' bit.
'poor reception' is the second definition.
'static' can be an answer for 'reception' (thesaurus). I'm unsure of the 'poor' bit.
'of' is the link.
Can you help me to learn more?
(Other definitions for static that I've seen before include "Not moving or changing" , "Unmoving, unchanging" , "Not moving - electrical interference" , "Still - radio interference" , "Its cat (anag)" .)