I'm tired of watching Lakers games in Standard with an HDTV

So I don't want something expensive, something that gets the job done,
I have a huge Antenna that was installed by the previous owner of the house on the roof, but someone told me I need to change from 300 to 75 Ohm, what's that and how to I do it?
Please guys my eyes are hurting, I need Kobe in HD... No homo
