As always , attics and inside buildings are/is not a reception friendly environment and never will be a reception friendly environment.
Multi-path/reflections signals bouncing all around , absorbing , blocking , broadcast Tv reception.
____
Here is the Federal Antenna Law that says Yes you can install a Broadcast Tv Reception Antenna of Any Size Above The Roof in such a manner to have Reliable Broadcast Tv Reception.
http://www.fcc.gov/mb/facts/otard.html.
Start with a ANT751 antenna in the attic aimed at about 194 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Also install a Winegard LNA-100 'Boost' amplifier.
For 1 Tv connected use No splitter.
For 2 Tv's connected use a simple common 2 way splitter.
For 3 Tv's connected use a simple common 3 way splitter.
______________
If there are reception issues that are not resolvable by adjusting the aim and location of the ANT751 antenna in the attic.
Move and install the ANT751 antenna to Above The Peak Of The Roof in such a manner that reception is not blocked by the roof and house in the directions of , south west , south , south east , north.
Above the roof aim the ANT751 at about 194 degree magnetic compass direction.
With the ANT751 antenna above the roof , Test reception , without and with the LNA-100 amplifier. Might not require the LNA-100 amplifier with the ANT751 antenna above the roof.
____________________
As always , trees and tree leaves , plants and plant leaves , have a Negative effect on broadcast Tv reception and so buildings including your own roof and house and other obstructions.
It is best practice to install the ANT751 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 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 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'.
Scan for channels.
_______________________
Here are some alternatives to computer tuner/recorders.
http://www.epvision.com , Tuner/Recorders.
http://www.channelmasterstore.com , Tuner/Recorders.
_____________
The ANT751 antenna Can Not be connected to any coax that has active cable delivered services , cable tv service , cable internet service , cable phone service.
Yes coaxes that are in or on the house can be used or antenna distribution.
Active cable services Must Be on Separate coax.