How about downtown Boston! ;-)
I recall driving around Post Office Square and near the Waterfront listening to 1150AM after dark and hearing, some station battling it out in the background!!
Even though the directional pattern is aimed toward Boston, it's still only 5kW from ten miles away, and it doesn't penetrate the downtown Boston buildings well. Because of that, it has lots of dead and weak shadowed areas in downtown Boston and the Waterfront areas, where nighttime skywaves from more distant stations can interfere.
I worked there when it was the mid-'80s incarnation of WMEX playing oldies on Stuart St. in Boston (with WMJX "Magic 106.7" at the time), right in the shadow of the Hancock tower in the direction of the transmitter. It was in AM Stereo then, but the reception was so weak at the studios that we couldn't monitor air in stereo at night without hearing other stations in the background floating back and forth from side to side in our headphones (called "platform motion" that can happen in AM Stereo when two stations are oscillating against each other on the same frequency), and even in mono we still got 10k heterodynes from stations on 1140 and 1160 at night.
It wasn't possible to get a good quality AM Stereo aircheck from the air monitors at the station (and you wanted it from the air, not from the board, to get that classic WMEX reverb and compression). Fortunately I lived in Arlington at the time less than two miles from the Lexington transmitter, and it was loud and clear in AM Stereo on my receivers there where my then-girlfriend recorded some of my shows.
It comes in better, in the same direction but farther away from the Lexington transmitter, when you also get away from the tall Boston buildings. It's somewhat better in Boston neighborhoods like Dorchester than downtown, and I used to get many requests from all over the South Shore, and even sometimes the Cape at night. In the other directions at night when I was on, I rarely got any calls from west of Route 128, or north of Route 128/95, or the North Shore.
I'd guess that 1150, as WCOP, had a better signal in downtown Boston in the decades before most of the tall buildings existed. Its original call letters stood for Copley Square Hotel where its original studios were, a location where it doesn't come in very well nowadays in the shadows of the Pru and other buildings in the Copley Square area, but it probably came in fairly well there in the 1940s.
