Re: Aliens watching our television
It's really very unlikely that any outside listener would have picked up our signals sent before the mid-fifties - i.e. when Television became commonplace. Most of our signals prior to then were in wavelengths that tend to be bounced back to earth by the ionosphere - deliberately, I should note, since that gave them greater range.
But when we needed the greater bandwidth for TV broadcasts, we opened up the VHF and eventually UHF area bands. These punch right through the ionosphere, no bounceback, and since the mid to late 1950s Earth has been one of the brightest radio sources in this part of the galaxy.
(The earliest TV broadcast was the famous 'cast of the 1936 Berlin Olympics - but that was neither a powerful transmission, nor a very long one.)
An advanced civilization COULD detect our earlier radio signals, but they'd need to be A) lucky, and using something similar to the Very Large Array that SETI uses to search for - well, exactly that sort of evidence.
So, a civilization 50LY from here would probably have just become aware of our existence. One 100LY away would know nothing of us, unless they were phenomenally lucky. One 25LY away would probably have told us to SHUT UP by now...