Just for fun I tried the cheap Chinese radio on 648kHz that was the subject of this thread:
https://www.vintage-radio.net/forum/...d.php?t=184986
I can just about hear Caroline here, 3 miles North of Manchester, the limiting factor seems to be the co-channel interference. the most dominant interfering station is producing a 2Hz beat with Caroline. I would have thought that's quite a lot, given the easy access to GPS frequency reference these days.