Indianapolis has 2 VHF digital TV stations, so you need a combination VHF-high-band plus UHF antenna. I would suggest using a Winegard HD-7696P or an AntennaCratf HBU-44 mounted on top of your existing mash with your antenna aimed at roughly 8-10 degrees compass point. Use all high-quality RG-6u coaxial cable from the antenna to your TV set, and be sure to ground the antenna cable where it enters the house to avoid static-discharge issues with your TV set. You'll see all of the Indy stations without a hitch.
http://www.winegard.com/kbase/upload/HD7696P.pdfhttp://antennacraft.com/pdfs/HBU44_.pdfhttp://manuals.solidsignal.com/AntInsta ... ampaign=CJ