You have a UHF antenna the DB8.
Aim the DB8 at about 335 degree magnetic compass direction.
KFSV , CBS is on channel 12 VHF.
Install a Winegard YA1713 VHF antenna aimed at about 306 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Combine the DB8 and YA1713 with a UVSJ = UHF/VHF/Separator/Joiner.
Type these letters in the solidsignal search box -> uvsj.
The DB8 will be connected to the UHF connection.
The YA1713 will be connected to the VHF connection.
The AP8700 will be connected to remaining connection of the UVSJ.
Here are some places to buy antennas and etc. ,
http://www.solidsignal.com ,
http://www.winegarddirect.com ,
http://www.amazon.com.
Rescan for new channels.
It is a good idea to scan for new channels from time to time because new Digital Tv stations/channels can begin transmitting with no prior notice.