Anybody have a good antenna design for the new UHF digital TV
stations?

I get reasonable results from my old VHF/UHF antenna (55% signal
strength) , but it's big and ugly, and I want to replace it with a
smaller, more efficient UHF design (maybe a Yagi) I can construct at
home.

Anybody know the dimensions of such an antenna, probabaly in the
frequency range of 400-800 Mhz ?

-Bill