If this is a Condo that is being bought or is owned. Then the buyer/owner of the Condo has the right to install and use a antenna mounted above the roof. Here is the Federal Antenna Law that says Yes you can.
http://www.fcc.gov/guides/over-air-r...n-devices-rule. The ANT751 or ANT751R will work real fine , aimed at about 145 degree magnetic compass. Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html. Here are some roof top antenna mounts ,
http://www.ronard.com/909911.html ,
http://www.ronard.com/34424560.html ,
http://www.ronard.com/ychim.html ,
http://www.ronard.com. Buy the ronard antenna mounts at solidsignal by typing the word ronard in the solidsignal search box or buy from ronard.
http://www.solidsignal.com. Does the Condo have a attic??