Maximum Usable ETI Transmitter Gains
This graph shows the large variation in predicted transmitter gain capabilities of ETIs. Note in particular, that the late Barney Oliver had limited the maximum usable uplink gain to 94 dB, whatever the type of transmitter, i.e., microwave or optical. He did not believe that ETIs would have the technical prowess to do the precise point-ahead targeting required for such narrow beams.
It is the resulting 60 dB impairment in uplink gain compared to the author's optical scenarios, that has so crippled the efficacy of the optical approach to SETI, that sure enough, comparative analysis will indicate that microwaves are superior. See the Cyclops Report to see how the comparison was grossly skewed in favor of microwaves by limiting the advanced ETI civilization to an uplink telescope diameter of only 22.5 cm - smaller than the telescope being used by The COSETI Observatory to detect such signals!
Copyright (c), 1993, The COSETI Observatory