Why do want to try to find aliens anyway? They might want to eat us or something. Also, why do they assume that aliens can even send and receive signals through space? If aliens exist, they probably aren't hyper advanced benign beings that want to share technology and have sex with humans, like they seem to be hoping for.
I get this is 99% sarcasm, but for those that might not know any better, obviously it would be impossible to communicate with any alien intelligence found using SETI. It would just be looking for proof aliens exist, searching for alien radio waves. For example, if aliens had their own SETI project, they'd likely detect us by watching television of Hitler, as the Germans had some of the first TV broadcasts, or they might watch an I Love Lucy episode, right from the radio signal it aired sixty years ago. If they detected a signal from Earth today from 1943, and sent a message to us, it wouldn't get here until 2078. So we wouldn't be communicating, so much as sending massive data bursts of our entire histories and technologies that took decades to reach each other. As far as finding aliens? Well, all the radio signals we sent out, if aliens are looking to eat a planet, we are already the prime candidate. This is simply to find aliens. If they're looking for us, we are already screwed.