Homemade low power TV transmitter?

[colorfixer]

Most low power UHF translators are fed from an existing NTSC transmitter which is transposed from one RF channel to another without taking it down to baseband (video/audio).

If they are exempt in the U.S. (they won't be in Canada), they will be in an interesting position. When the feeding analog transmitter (usually VHF, sometimes another UHF translator/transmitter) is no longer available, they will cease to function.

I haven't yet tried transposing a digital signal from one channel to another.