Off hand, I doubt TV signals would be very easy to decode at that distance. First of all, I don't think that frequency range carries all that well when you're talking about interstellar distances. The VHF channels 2-13 are 6 MHz wide (at least in countries that use the NTSC standard) from 54 to 216 MHz. The UHF channels 14 to 83 are also 6 MHz wide and run from 470 to 890 MHz (see this reference). I'm not positive but I think the upper 13 channels have been reclaimed because they weren't being used.

One problem with TV signals is that they're broadcast over a wide area horizontally. Even though a typical TV station broadcasts a pretty powerful signal, the wide antenna pattern means the signal is pretty weak. While the transmitter antenna probably tries to concentrate the emission in the horizontal plane, you're almost getting to an inverse square law situation with the 360 degree pattern.

To put this in perspective, when I was doing satellite supports, our uplink used a very narrow beamwidth (0.1 degree) antenna that effectively amplified the radio signal by about 2 million times (63 dB) compared to a dipole antenna. We used a 1000 watt transmitter for our carrier. By the time the signal reached a satellite in geosynch, the measured signal strength was typically in the range of -82 to -87 dBm (extremely weak). RF signals use strength rapidly. Add to that the fact that a Channel 2 signal from one place might interfere with a Channel 2 signal from across the country, which would make it even more difficult to sort out a particular signal.

The video component of TV on the NTSC standard uses 525 scan lines with interlacing. Every other line is broadcast in 1/60th of a second and then the gaps are filled in in another 1/60th of a second. This gives an effecive frame rate of 30 fps. Many other countries use different numbers of scan lines and frame rates. Here's an explaination of how Australian TV signals are encoded. It sounds like the European PAL standard. Anyway, substitute 525 for scan lines and 30 fps for frame rate and you'll get a pretty good explaination of how our signals are encoded.

Personally, I suspect the most detectable RF signals from Earth would be Radar, especially the very powerful radars line BMEWS. These signals are narrow band and are more concentrated in direction. They also are more repetitive in things like pulse repetition rate (PRR) and pulse width. I think these consistencies would make it easier to determine the signal was artificial, especially when the radar changes modes on the same frequency (something a pulsar can't do).