Thanks for the replies. I am sure it is the antenna. The Leaf is definitely directional. NBC lies the lowest in the VHF range according to antennaweb. It has to be something odd between this particular antenna, this particular frequency, and possibly even the tuner in the Tivo.
I left the rabbit ears in the attic at my home....we are leasing it to some friends temporarily. I will just go buy another set and try them either on their own or in combination with the Leaf and hopefully come up with something.
It would not be an issue if FOX had not recently switched affiliates here and moved to ch. 9. They were on 12 before...and that channel comes in fine...but there is nothing worth watching on it now.