Getting a file format that works for everyone is very complicated. However, if you are are trying for network news, it is safe to use MPEG-2 TS 1080i29.97 (CBS, NBC, CNN) or 720p59.94 (ABC, Fox) at CBR 50Mbps, 15/3 closed GOP. Audio should be 48kHz PCM.
Local stations will accept MP4s, but you likely won't be happy with the results once it gets to air. The same goes for 1080p and 24fps flavors. Be especially careful that you have not mixed frame rates on your timeline. Pre-convert any elements that are not in the target frame rate before adding them to the timeline.
For local stations, it may be best to contact them individually. It often helps to ask if they will be transcoding an MP4 to another format and if you can just provide that format.
Be careful of any spec sheets you find publicly accessible. They are generally written for commercial copy and not for contribution content. There may be differences.