TV channels 2, 3, 4, and 5 will get clobbered by the junk going up to 80MHz.
The video signal is AM modulated onto the channel carrier (with a
portion of the
lower sideband suppressed) and will have no ability to reject the BPL
noise.
The effect would be somewhat similar to a sparky vacuum cleaner motor
throwing
white and black spots throuout the picture. The sound, being FM, will fare
better. Well, there's digital HDTV, but most everyone still uses analog TV.
And I don't get cable or satellite.

2 to 80 MHz is the spectrum that the BPL folks asked to try in their
experimental license applications. I have not seen any BPL above 50 MHz -- so
far.

And at the levels I have seen BPL, digital TV won't help. The digital TV
demodulation process can ignore noise up to a point. An analog TV signal that
was somewhat noisy, but perfectly watchable, would probably be clean on
digital. An analog signal that was noisy, but still just watchable would have
many digital errors that would result in portions of the screen locking up for
a few seconds at a time, loss of audio for seconds, etc. And just a little bit
past that point, the digital TV signal would fall apart all together.

73,
Ed Hare, W1RFI