> also how did CTRC allow 93.1 to be
> operated in Vancouver? This station is very short space with
> 92.9 KISM.
Actually the CRTC has nothing to do with that, it's up to the Department of Communications to decide whether a given frequency can be used at a given power at a given location. Once the Department decides whether a facility is technically acceptable, then the CRTC decides which applicant will make the best use of that facility. It's as if the FCC were split into two agencies, with the engineering folks going one way and the lawyers going another.
Anyway, when considering interference, officially broadcast signals don't cross the border. (of course, we know that from a technical standpoint that's bunk!) If the new Vancouver 93.1 station causes interference to KISM in Canada, the Department doesn't care -- from an official standpoint, KISM cannot be received north of the border. Likewise, if KISM causes interference to CKYE in the U.S., the FCC doesn't care since officially, CKYE cannot be received south of the border.
I'm sure this doesn't make KISM's sales department's jobs any easier though!