The SNR to Mars is not great at the best of times. We no longer radiate a great deal of high-power analog signals, because those are not efficient. Space is noisy, digital signals look very much like noise, and radiating to space is not usually the most efficient thing to do if you can avoid it. Our chances of detecting our own planet even from the nearest star would be pretty minimal. Perhaps someone might be able to explain to me why we postulate being able to detect extrasolar aliens.