CBOT is on VIRTUAL channel 4.1, but actually operates on UHF channel 25. This identification is known as PSIP, and is supposed to help you follow your TV channels by virtually renaming them to their old analog channel numbers. Don't worry, the US has had PSIP for years now, and people STILL don't get it...LOL If you look at your TVFool.com report for digital stations, you'll see the REAL and the VIRTUAL channels listed. The REAL channels are the actual channel on which your digital operates; the virtual channel is the simulation of the old channel number that you have known for years, with a suffix .x after the channel number. It was supposed to help you figure out the new channels by disguising them as the old channels...LOL.
Because your house has some aluminum siding and brick exterior, the UHF channels will have a harder time penetrating your house, and you will likely experience some signal drop-outs , especially when people move around the room. Unfortunately, the only cure for that is a properly designed and installed antenna system. Very directional indoor antenna systems can help some, like the HDTVi or the HDTVa from Terk, but don't expect miracles in this case: all indoor antennas are limited by the environment in which they operate. In any event, indoor VHF antennas are really nothing more than a pair of rabbit ears with some sort of UHF attachment on them, so they all perform pretty much the same on VHF.
Here is a reprint of you digital TVFool.com report: I believe that it will explain things a bit better.
http://www.tvfool.com/?option=com_wr...8387353a3e35d7
Click on the selector button to see the PENDING digital-only stations: it is the closest to what is actually happening in Ottawa at the moment.