ETIs have vastly superior technology and access to
enormous sources of energy. To make their signals easily detectable and to send a rich
data-stream to emerging technical civilizations (us), they will be guided by the
||ETI laser technology is very mature. It is
easier for them to send out strong signals than for us to build large arrays to collect a
few of their photons.
||They can observe and predict the motions of
suitable nearby targeted extrasolar planets, allowing for beams smaller than stellar zones
||Lasers make it easier and more energy
efficient to multiplex beams onto a large number of suitable targeted planetary systems.
||Lasers are capable of producing very high
EIRPs and supporting high modulation bandwidths. Pulsed signals, with their high peak to
mean power ratios, are far more detectable against the ETI's stellar background.
||To overcome problems from the lack of
apparent magic optical frequencies, Doppler shifts/chirps and
frequency search time, they will use pulsed signals. This eliminates the need for narrow
bandwidth optical filtering at the receiver.