Having a problem getting my folks ready for the DTV switch, wanna help?

So my parents are of the few people left in America that do not have cable TV, satellite TV, or whatever else is on the market. They have, as long as I've been alive, always used regular over-the-air broadcast TV. I'm trying to get them ready for the change to DTV that's coming in February. I have my father's TV in the family room working fine. Just have the converter box plugged in to it, he gets all the DTV channels. The TV in the bedroom that my mom watches has both a converter box and and a VCR/DVD recorder. The recorder has a DTV tuner built in to it, So just like she used to she can record on one channel and watch something else on another channel. The problem I'm having is that my mom's TV does not get all of the DTV channels, only about half of them. I get the same channels with either the converter box or the recorder. The only real difference I can see is that my dad's TV is connected to an outdoor antenna and my mom's TV uses an indoor antenna that said on the box it works with DTV.

Any suggestions on what to do to fix this?

I think I'm going to have to connect her's to the outdoor antenna. I'm not sure though. The old "rabbit ears" also had trouble with some stations.