For the last few months CBC radio reception has had a loud transformer hum or howl in the background. I can hear the voices clearly but this hum is quite aggravating. Occasionally it disappears, but then it's back. This is Edmonton radio 2, I notice similar deficiencies in other CBC channels around the region.
Interestingly, Calgary seems to come in loud and clear. Most CBC listeners would not recognise Calgary CBC to be a Canadian CBC station. For this reason I think this problem is political in nature rather than 'just technical'.
I'm quite sure the actual fix is technical but somebody somewhere has made a decision to degrade the CBC broadcast on this platform.