SonoSational18:
A little clarification on your clarification:
1190 was in fact designated as a "Clear Channel" and WOWO was licensed as a "1B Clear" until deregulations in the 80's began to dismantle the AM band's systematic licensing.
1190 was (and still is) 'notified' as a US Clear Channel, with the dominant stations being WOWO in Ft. Wayne and KEX in Portland.
There are/were both 1A clear channels (700, 890, 770 and 1040) and 1B Clears (1000, 1190, 1520 and 1530).
Each of the 1B clears had to protect each other, but nobody else and no other station in American could interfere with them.
In other words, WOWO had a gentle null to the west to protect KEX in Portland, WCFL/WMVP in Chicago and a gentle null to the west to protect KOMO in Seattle ands WCKY in Cincinnati has a gentle null to the west to protect KFBK in Sacramento.
The fact that there are 2 dominant station on their frequency only makes them slightly less effective as their 1A counterparts.
Most of the 1B clears proudly proclaim they are 50,000 watts heard in 38 states at night, just like the 1A clears.
Even though WOR (710) is directional at night to protect KIRO in Seattle, it is still a fairly easy catch here in Central Indiana.
When WCKY (1530) in Cincinnati switches to their directional plant, you can barely notice it here in Indiana, both groundwave and skywave remain fairly constant after they make the switch.
Station are no longer referred to as 1A clears and 1B clears, all of the original 1A and 1B clears are now classified as Class A's.
It reverts back to their historical classification for the purpose of licensing. There are now several full-time 50,000 watt stations, but they are class B's because of who they must protect and who must protect them (they get no secondary coverage protection). A good example of this is WFLF in Pine Hills (Orlando) Florida, which is 50KW 24 hours but they are directional day and night and are only a class B.
There are lots of exceptions to the rules involving clear channels, such as Dallas's 1190 (50KW days 5 KW Nights DA2)
and even Shelbyville's WRFD on 1520 got sandwiched between a couple of 1B clears, WKBW in Buffalo and KOKC in Oklahoma City.
And these days, there are nighttime station on former 1A clears channels like 700. WLW is no longer the sole occupant of 700 KHz at night and there is now an 890 being built in Florida (in WLS former secondary coverage area).