As always , Attics Are Not a reception friendly environment and Never Will Be a reception friendly environment because of signal attenuation and multipath/reflections - signals bouncing all around.
Install the FVHD30 , Above the Peak of the roof in such a manner that reception is not blocked by the roof and garage and roof and house in the directions of , north east , south east , south , south west.
Aim the FVHD30 at about 25 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/pointing/pointing.html.
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Install a Antennas Direct CPA-19 preamp.
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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.solidsignal.com , or ,
http://www.hollandelectronics.com.
Here are places to buy antenna system componets and etc. ,
http://www.solidsignal.com ,
http://www.amazon.com.
As always , trees and tree leaves do a good job of , multipath/reflecting , absorbing , blocking , Digital Broadcast Tv reception and so do buildings and other obstructions including your own roof and house.
It is best to install the FVHD30 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 house. The Tv/s Must Channel Scan for the , OTA=Over The Air , Digital Broadcast Tv stations/channels , often 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.
Some Digital tv's will automatic channel scan for cable tv channels.
DO NOT channel scan for cable tv channels.
Go into the Tv Setup Menu and select 'Air Channels' / 'Antenna Channels'.
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Digital Broadcast Tv Tuners can develop - Digital Glitches - that are not cleared out with simple channel scans.
Do a Double Rescan.
http://www.dtv.gov/rescan.html.