Or, there are no aliens to listen to.
Are either of you guys aware that the NSA has posted partial decodings of ET messages? Their public web site contains a PDF file that describes a signal, an evaluation of whether or not the receiving stations followed correct signal identification protocol, and finally keys of cipher. They conclude that the message is a periodic table of the elements with one extra parameter for each element.
They also indicate that a number of other messages remain untranslated.