Distortion affecting my radar beam (7)
I believe the answer is:
yardarm
'beam' is the definition.
(type of wooden beam on a ship)
'distortion affecting my radar' is the wordplay.
'distortion affecting' is an anagram indicator (a distorted version of the letters).
'my'+'radar'='myradar'
'myradar' is an anagram of 'YARDARM'.
(Other definitions for yardarm that I've seen before include "First drink, when sun over it" , "Either end of pole supporting sail" , "End of spar on ship's mast" , "Extremity of beam supporting a square sail" , "End of mast's beam" .)