For reception of the Canada Digital Tv stations/channels to the , north west , down to and including CJNT-DT UHF channel 49 City Tv / Omni Tv.
http://en.wikipedia.org/wiki/CJNT-DT.
And WCFE-DT 38 PBS to the , south west.
http://www.en.wikipedia.org/wiki/WCFE-DT.
Above the roof install a Winegard HD7698P antenna with a Antennas Direct CPA-19 preamp , aimed at about 280 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Some common above the roof type antenna mounts are , tripod mounts , eave mounts , chimney mount.
For 1 Tv connected use No splitter.
For 2 Tv's connected use a , HFS-2D , 2 way splitter.
For 3 Tv's connected use a , HFS-3D , 3 way splitter.
Buy the HFS splitters at ,
http://www.hollandelectronics.com , or ,
http://www.solidsignal.com.
Here are some places to buy antennas and etc. ,
http://www.saveandreplay.com ,
http://www.trentondistributors.com ,
http://www.canadapost.ca/shopper.
As always , trees and tree leaves do a real fine job of reducing or blocking Tv reception and so do buildings and other obstructions.
It is best to mount the HD7698P antenna at a location that has the least amount to no amount of obstructions in the directions of reception.
The Tv/s Must Channel Scan for the Digital Broadcast Tv Channels , sometimes named the 'Air Channels' or 'Antenna Channels' in the Tv setup menu because the Tv transmissions travel through the air from the transmitting antenna to the receiving antenna.
DO NOT channel scan for cable tv channels.
The other USA Digital Tv stations are not receivable at the 20 foot antenna height.
To see how low or high will have to be for reception.
At tvfool in the the box that says enter antenna height , put in lower and higher antenna heights then 20 feet to get the some of the other USA Tv stations in to the Red reception zone or better yet into the Yellow reception zone.