Here are some 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.
Here are some places to buy antennas and etc. ,
http://www.solidsignal.com ,
http://www.antennasdirect.com ,
http://www.amazon.com.
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Yes it is Ok to use a indoor antenna such as the Trek HDTVa antenna inside the condo and what ever is received -> is what is received.
Start with the aiming direction at about 220 degree magnetic compass.
Here is how aim indoor antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
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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.