No matter what the antenna height , the reception of the Digital Canada and Digital American Tv stations that are in the green reception zone are easy to receive.
Above the roof of the house install a Antennas Direct Clear Stream 4 UHF antenna aimed at about 155 degree magnetic compass.
You can try reception with the CS4 in the attic of the house.
If the house does not have a metal roof and no metal backed insulation on the underside of the roof , reception should be fine.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Remove the reflector screen from the CS4 UHF antenna so the antenna will receive both the Canada and American digital stations/channels to the north and south/west.
The CS4 will provide signal to 1 thru 4 Tv's. No amplifier required.
Here some places to buy antennas and etc. ,
http://www.saveandreplay.com ,
http://www.trentondistributors.com ,
http://www.canadapost.ca/shopper ,
http://www.amzon.ca ,
http://www.solidsignal.com ,
http://www.antennasdirect.com ,
http://www.amazon.com.