Learn common article patterns for media: on TV, on the radio, on the internet.
Common collocations: on TV, on the radio, on the internet
Do not try to force one rule; many are fixed phrases.
Did you see it on TV / on the radio / on the internet?
💡 These are largely idiomatic collocations. British vs US note: both use 'the internet' commonly; for 'news' you may hear different prepositions (in the news / on the news). Learn the collocation for your target variety.
✓I saw it on TV.
✗I saw it on the TV. (meaning: the device)
On TV = medium; on the TV often means the physical television set.
✓They talked about it on the radio.
Radio commonly takes 'the' in this collocation.
✓I read it on the internet.
A very common collocation is 'the internet'.