Recent studies using econometric models to estimate television station viability have been applied to a proposal to "drop in" short-spaced VHF channel assignments in some markets, and to reallocate some UHF frequency spectrum to other users. This paper argues that VHF projections are more difficult to make than UHF projections, because FCC channel assignments place limits on the number of VHF stations so there are no data on number of stations a market could support if assignments were increased. This paper estimates a new model of UHF station viability. Results indicate that attainment of 100 percent UHF set penetration will not have much effect on the number of viable UHF stations, but that increasing income levels will. The number of commercial UHF stations will approximately double by 1990, leaving half of present channel assignments unused; thus some substantial reallocation of UHF spectrum to other users should be possible.