WPBS (nee WNPE)/WNPI in Watertown, NY (on cable in Ottawa) and WCFE in Plattsburgh, NY (on cable in Montreal and through much of Quebec) would likely go under if not for financial/underwriting support from Canadian viewers.They don't necessarily spend a majority of their time broadcasting from Canadian studios, but a large amount, if not a majority, of viewership and funds for PBS television stations Buffalo/Toronto Public Media (WNED-TV) and Prairie Public Television (KFME-TV, etc) originate from Canada.
Detroit's WTVS (in a border market to begin with) gained a nationwide signal footprint when it went on the Cancom satellite in the mid-'80s and contributions from Canadian viewers no doubt helped keep them stable. I used to be amazed that they'd mention getting pledges from places like Alberta and Nova Scotia whenever they did pledge drives.