CBS has news stations all over the country and a TV affiliate in every market. Merlin just has New York, Philadelphia, and Chicago. They had a chance to get into Washington DC via 107.9 FM, but were outbid by CBS.
Now that I think of it, I think Merlin had a conservative bias all along. I remember tuning between the news stations on November 15 and 17 when Occupy Wall Street was raided, and when they had a big day of action respectively. FM News 101.9 aired some fluff segments, and only briefly mentioned Occupy (they had to, lower Manhattan was a mess both of those days), while both 880 and 1010 devoted about 33% of their coverage to Occupy, and had reporters in Zuccotti Park, since that was the biggest news story in New York those two days. I'd expect CBS to devote the same amount of airtime if the Tea Party had a major rally that would be the biggest news story in New York. Ironically, WBAI was airing recorded liberal talk shows reporting 12-hour old news about Occupy.
Yet, FM News 101.9 airs a nearly meaningless speech from an unpopular Republican candidate in its entirety, in a region that mostly votes Democrat.