Skilful in adjusting the radio - a famous old model (6)
I believe the answer is:
adroit
'skilful' is the definition.
(adroit can mean skilful or masterful)
'adjusting the radio a famous old model' is the wordplay.
I cannot really understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
an anagram of 'radio' is 'adroi' which is within the answer.
No letters remain.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for adroit that I've seen before include "skill" , "Quick and clever in action or thought" , "handy" , "Quick and deft" , "Nimble and skilful" .)