Over the air digital tv signals can be really weird. I live within 2 miles of the tower from which all major stations broadcast in D.C. I am on the top of a hill and no buildings come between my attic and the tower. Yet I have trouble with the WRC-TV, the NBC O&O, particularly when it is windy. There is no good explanation for this and the chief engineer at the station really doesn't believe there is a problem.

Most of it went away when I installed a ChannelMaster omnidirectional antenna with an amplifier in the attic. I doubt that I would get WRC at all with rabbit ears. The message here is that you might try installing an amplifier on your roof antenna to see if you can get all those stations without the converter box.

Bob