Header Cut Off on Large Screen

Our responsive website raingod.org, has not had any problems that I’ve been aware of. However, upon pulling it up at the very large monitor at my dad’s desk, the top and bottom of the header are cut off – in both Chrome and IE. Now my dad consistently did insane things on his computer and I’m hoping this is a problem with his settings. Is there some way for you to test it or is there a reason the header would be cut off on a very large screen? I HAVE run online tests for responsiveness with no problem. Thanks! Bruce