[halfdan]

What signal are we expecting to be able to detect? AFAIK the radio signals we've been emitting are garbled beyond recognition and way too weak even a few light-years away from earth. After all, most of our communication is directed at earth and the remainder is for at most geo stationary orbit. We generally don't transmit anything high energy that would stand a chance to be recognisable from afar.

Similarly signals from other civilisations will probably become scrambled by distance and because they might overlap heavily with the radiation emitted by their sun.