Marconi goes out to a Spanish island (7)
I believe the answer is:
minorca
'to a spanish island' is the definition.
(Minorca is a Spanish island)
'marconi goes out' is the wordplay.
'goes out' indicates an anagram.
'marconi' is an anagram of 'MINORCA'.
(Other definitions for minorca that I've seen before include "One of Balearic islands" , "Land in Balearics" , "Mediterranean island" , "Balearic island; O, cram in (anag.)" , "Balearic island (Eng. sp.)" .)