The first thing I would do is buy a six or twelve foot extension to allow the antenna to be moved throughout the room.
https://www.google.com/?complete=0#c...=rg6+extension
Indoor antennas are affected by people walking near them and even appliances and other metal objects in the house or building. Most of your stations are to the east and southeast, so anything you can do to facilitate a clear shot in those directions is bound to help. Also, if you are rescanning with every antenna change, I strongly suggest you try to find a way to manually add channels to the television or converter. Check the setup menu, but sometimes all you have to do enter the real channel number on the remote, possibly followed by a period or hyphen. Don't be surprised if you see nothing on the screen initially, since modern televisions typically don't show a picture unless a usable signal is present.