"Peter H." wrote in message
...


Then I think most of us are using the popular term which meant there was
only
one station on the frequency. Not even a daytimer shared it.


U.S. Class I-A clears a 640-670, 700, 720, 750-780 820-840, 870-890,
1020-1040, 1100, 1120, 1160, 1180, 1200-1210


Canadian Class I-A clears: 540 (first), 690, 740, 860, 990, 1010, 1580

Mexican Class I-A clears: 540 (second), 730, 800, 900, 1050, 1220, 1570

I'm having trouble thinking of a single U.S., Canadian or Mexican Class
I-A
clear channel which did not have at least one co-channel daytimer
somewhere in
the U.S.

Very old examples would be WOI in Ames on 640, KVFD/KPOP/KGBS on 1020, KOB
and WEW on 770, Kannapolis on 760, Lansing on 870, Oklahoma City on 890.
1100 in San Francisco. 1160 in Chicago. 660 in Dallas.

And, remember that stations in the U.S. territories (and former
territories,
now states) were allowed to operate on U.S. Class I-A clears many decades
before "Rio" caused all clears to be completely broken down.

650, 760, 830, 870, 1040, 1210 in Hawaii. 660, 700, 750 in Alaska.