Some back of the envelope calculations on diffraction limits suggests that we'd be very lucky to get 10^-18 of our transmitted energy back, even if we used the

Some back of the envelope calculations on diffraction limits suggests that we'd be very lucky to get 10^-18 of our transmitted energy back, even if we used the entire planet as a transceiver dish and Voyager was a perfect reflector. I would put this into the "very, very impossible" category.