KAXT in Santa Clara, California has twelve video channels along with eight audio-only channels.
Doesn't a station offering more subchannels affect their main HDTV signal compared to TV Stations without subchannels.
All stations have the same amount of digital bandwidth to work with. Just depends how it is divided up.
Not all digital stations have an HDTV channel. Going all standard-def allows for more subchannels. And if HDTV is involved, 720p uses less bandwidth than 1080i.