[eridius]

The wikipedia page on Path Loss[1] suggests that radio and antenna engineers typically model path loss (in decibels) using the formula

  L = 20 * log10(4 * pi * d / λ)

(where λ is the wavelength and d is the distance between the transmitter and receiver expressed in the same units as the wavelength)

If I'm doing the math right[2], this says that the path loss over 1 lightyear for an 80MHz transmission (which seems to be in the analog TV range?) is something like 330 decibels. Now I'm not sure how strong TV transmissions are, but I'm guessing it's not that strong.

Darn. Seems Futurama and every other piece of mass media that claims that aliens are watching our TV from 80 years ago is wrong.

[1]: https://en.wikipedia.org/wiki/Path_loss

[2] Which is to say, if I'm typing it into Wolfram Alpha correctly.