They're often local call letters (ex WNBC). Search for major TV stations on the coasts & try those.

Some of the providers I've use don't provide the EPG for the West Coast feeds

I use XML-tv.com EPG service and TV Mate and fill in the blanks

For cable/premium channels (Disney, HBO, Showtime, etc) that have a west coast feed, you add the same EPG-ID for both channels, then in your IPTV app you need to change the Time Offset for the West channel +3:00. It is VERY important that you figure out how to do it PER CHANNEL on your app - for example, in TiViMate, you highlight the channel in the EPG, open the menu, go to Channel Options, then scroll down to Time Offset. If you change the global EPG offset, it will shift EVERYTHING to the wrong time (except the west feeds lol).

It is important to note that this will NOT work properly for local networks for the most part. Local affiliates of the same network (WNBC NY and KUSA Denver for example) are not just the exact same channel offset by 3 hours like say, Disney East and West would be. They don't always run the same shows in the same time slots, and programs that would be in the correct slots such as local morning shows will not show the correct host/guest/discussion info. It would just show the guide info for the New York affiliate, offset by the correct time. Sometimes things will land right, but not always.