WEPN 1050 will switch to ESPN Deportes in Sept. English-language ESPN fare remains on 98.7 FM. 1050 NYC protects Toronto, Mexico,and KYW.The null KYW has in Bucks Co. protects 1050, and both stations are reduced to sideband gibberish in much of NJ. I had heard of WMCA's CP for 50 kW. The pattern would have to be very tight to protect Philly and WFRB in MD. 50 kW at 570 would be a monster over water to the Bahamas or Bermuda.
WMCA had a CP for 30 kW-D not 50, I believe (or maybe, it was 50 kW-D/30 kW-N). Six-tower teardrop. Three of the six towers would have been the existing three. The additional three would have been in a parallel line. The six-tower setup, which WNYC 820 also uses, would probably have allowed WNYC to increase its night power, which is currently only 1 kW and doesn't fully cover the five boroughs at night.
As for WEPN protecting CHUM--I don't think so. Each one sends plenty of signal toward the other at night. Both protect the Mexican border, however--by international treaty. WEPN's protection of KYW is a consequence of WEPN's protection of the Mexican border. By treaty, WEPN and WHK 1220 in Cleveland (both 50 kW-U on Mexican ex-IA channels) are DA-1. The treaty requires the stations to use their night patterns, which have deep nulls toward Mexico, at all times. If there were no treaty requirement, WEPN could not have been DA-2 because any null fill-in to the southwest would have interfered worse with KYW, a higher class of station (ex-IB) than WEPN (ex-II). As far as KYW relaxing its pattern to the northeast, it's out now. There is now a full-time station on 1060 outside of Boston (50 kW-D/2.5 kW-N DA-2). The night pattern uses five towers and is deeply nulled over a 210-degree arc centered at 270 degrees true. The towers are very tall (205 degrees) to minimize high-angle radiation, thereby further reducing the interference to KYW.