Broadcasted

[ROBINDESBOIS]

This event is bradcasted on all tv stations or by all tv channels?

[Perikles]

This event is bradcasted on all tv stations or by all tv channels?Neither. Many options but I would say

This event is being broadcast on all TV channels.

(broadcasted is an American option, so wrong :D)

[Rusty]

(broadcasted is an American option, so wrong :D)The past tense 'broadcast' is preferred in AmE, but it's true that we have the option to add 'ed'. I personally never do. :)

[ROBINDESBOIS]

I like it better it has a regular past tense identity. Question of taste I guess !