radio set vs receiving system

radio set and receiving system both are nouns.

Word	Noun	Adjective	Verb	Adverb
radio set	Yes	No	No	No
receiving system	Yes	No	No	No

As nouns, receiving system is a hypernym of radio set; that is, receiving system is a word with a broader meaning than radio set:

radio set: an electronic receiver that detects and demodulates and amplifies transmitted signals
receiving system: set that receives radio or tv signals

Other hypernyms of radio set include receiver.

radio set (noun)	receiving system (noun)
an electronic receiver that detects and demodulates and amplifies transmitted signals	set that receives radio or tv signals