What does the cryptic crossword clue "Old-fashioned medium broadcast modest aria (5,5)" mean?

The definition is "Old-fashioned medium". The wordplay uses an anagram. anagram of MODEST ARIA = STEAMRADIO The answer is STEAMRADIO.

Old-fashioned medium broadcast modest aria (5,5)

Guardian Cryptic #29495 | 17 Across | 2024-09-23 flower