In the wee hours of both May 2, 1988 and October 15, 1989, while DXing from Iowa City, I caught WBBM completely off the air and, both times, heard what sounded like opera music, albeit faintly. But neither time did it ever rise up strong enough for me to get an ID. To this day, I've always wondered if it was Radio Coro that I had snagged.
BTW, Rick, thank you for the tip on WELD-690. Heard them on the Muscatine, Iowa KiwiSDR last night.
73,
Rick Dau
South Omaha, Nebraska EN21af
Kenwood R-5000 + Quantum QX Pro v2.0
Sony ICF-2010 + Grundig AN-200
ICOM IC R-7000 + CCrane FM Reflect antenna
Sangean ATS-909X
Midland WR-300 weather radio
http://www.hard-core-dx.com/article.php?story=20190216172824280