The Canadian Radio-television and Telecommunications Commission today approved a nighttime power increase and pattern change for CFRA 580AM in Ottawa. The change will significantly improve the station’s signal, particularly toward the East, putting Montreal inside its 0.5mV/m contours at night.
Like most AM radio stations, CFRA is required to protect other stations on the same frequency at night, when AM radio signals carry much further. Specifically, it was required to protect the following 580AM stations, all of which have now moved to FM (and all of which are private commercial music stations):
- CJFX in Antigonish, N.S. (at 98.9 and 102.5 FM exclusively since 2003)
- CKPR in Thunder Bay, Ont. (at 91.5 and 93.5 FM since 2007)
- CHLC in Baie-Comeau, Que. (at 97.1 FM since 1996)
The result is a speech-bubble-shaped pattern pointed heavily toward the north, northeast and northwest (the transmitter site is due south of Ottawa).
With these stations gone from this frequency, and no expectation that anyone would try to reactivate them in these small markets where there are still FM frequencies available, Bell Media Radio successfully convinced the CRTC that it should allow CFRA to increase its nighttime pattern to have better coverage toward eastern and western Ottawa suburbs at night. The fact that no one objected to the application also convinced the CRTC that this was a good idea.
Under the approved technical parameters, CFRA will drop from 50kW to 30kW at night (instead of from 50 to 10). The pattern shape will also change slightly, still speech-bubble-shaped but a bit less directional toward the north, improving its signal toward the southeast and southwest.
According to the broadcast engineer’s contour map, the 0.5mV/m contour, which under the current signal goes through Deux Montagnes, Rigaud and Alexandria, will now cover all of Montreal, Laval, the north shore and Châteauguay and Valleyfield regions. It’s hard to translate that into actual receiving abilities (which are dependent on the type of radio and local interference sources), but it will be an improvement.
According to a story on CFRA’s website, “CFRA Chief Engineer Harrie Jones says the technical work will begin soon, and he’s hopeful the affected listeners should hear a difference within a month.”