Re: Not useful
Why beam a transmission? For the very reason stated; distance. Space agencies are already in the process of developing optical communications systems, as the amount of data being produced by deep space probes is exceeding the bandwidth capabilities of current RF systems. The shorter the wavelength, the smaller the beam divergence, given the same minimum beam width (waist). It would make more sense to limit the search to civilizations achieving interplanetary travel, since our only data source indicates a move to optical communications within 100 years. We should be looking at UV or shorter wavelengths, not radio. We ourselves have only been using radio for a bit over 100 years and already have moved to primarily optical communications for all but short distances.