For what it's worth: Back in the earlier 60's, WNYH Huntington (originally WGSM) was 1000 watts omni, and a strict daytimer.
When they went to 5000 watts they had to add two towers and steer clear of WVCH in Chester PA. They were still a strict daytime-only station.
Then came 25,000 watts. The facility was 'WGSM' at the time, but had to add a fourth tower -- to keep avoiding WVCH. Here's the latest daytime map, courtesy of Radio-Locator. Look at the huge null southwest.
https://radio-locator.com/cgi-bin/pat?call=WNYH&service=AM&h=D
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We lived and DXed from just above the 'r' in 'New York' on the map. WGSM always was on top of 740 in the midday. But WVCH was always there, faintly but gurgling steadily underneath WGSM, through the 60's.
WJBR Wilmington DE was another station from that way which was *always* under the super-directional Long Island station WGLI 1290. As WGSM did, WGLI
had their towers northwest of the COL and lasered the wattage right through the place and out to Bermuda.
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Ironic footnote : WGSM ran a contest the day they went to 25,000 watts. I believe that would have been in the late 70's. Anyway, the contest ran along the lines of the first correct-answer caller to something-or-other won $25000.
Legend has it that the VERY FIRST CALLER won the $25,000. End of contest. First caller.