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For improved reception.
Above the roof in such a manner that the roof and building are not , obstructing , impeding , blocking , reception in the directions of , All Directions.
Install a ,
http://www.channelmasterstore.com , CM5016 All channel antenna.
Or a ,
http://www.antennacraft.net , C290.
Or a ,
http://www.antennacraft.net ,
HD850 ,
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Aim the antenna at about 200 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Use a Real and Actual magnetic compass to aim antenna.
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As always , trees and tree leaves , plants and plant leaves , have a Negative Effect on Broadcast Tv Reception and so do buildings and other obstructions including your own roof and building.
Some and not all Negative Effects are ,
Absorbing , Blocking , Reception.
Multi-Path Reflecting Tv signal bouncing all around.
The Best Practice is to install a antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including your own roof and building.
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