DJG, not much help to you, but I have had no problems getting CTV RF8.

Nothing new blocking line-of-sight to the CN Tower?

Other CN Tower stations okay? If so, the fact that it's VHF is the only difference from other CN Tower stations. I like Nueatit's suggestion that a pre-amp, if you have one, might be defective in the VHF band. If you plug an antenna directly into a tuner without a pre-amp, you should be able to get a fair signal in Mississauga, so you'll know if it's the pre-amp or not.