There is an interesting site that shows the history of Canadian stations. CHFI/CFTR and the CHLO history is complicated. Bill Dulmage is the editor of the site. I wondered about the 680 pattern for CHLO. Bill had a coverage map but only so much was shown and little of the US coverage. I wonder if Scott Fybush has any details. It was a parallelogram and was 1000 watts DA-1, but had a fairly large lobe to the West, which puzzled me because it had to protect KNBR under treaty skywave curves.
I'd be interested in seeing that if you have the link. If not, no worries. Wasn't CHLO on 1570 at one point?