Combined Pulsed Laser Beacons & Signals

9907-001

This updated illustration contains numbers indicating possible respective transmission powers, EIRPs and the number of photons per beacon and signal pulses that might be expected to be detected by a 100 meter aperture telescope at a range of 100 light years.   A large photon bucket (100 meter effective aperture) is required to ensure a high probability of discriminating a signal (data) photon during the correct time-slot.   For the purposes of this scenario, it is assumed that the mean power in the wideband data signal (10 GW) is ten times the mean power in the attention-getting beacon signals (1 GW), i.e. that the ETIs devote much more power to their main data signal than to their beacon.

The mean signal (data) power and the receiver aperture in the above illustration are each ten times larger than assumed for the earlier illustration 9408-002.   A more detailed version of the 3-dimensional interstellar beacon diagram may be found at 9512-001.

Copyright (©), 1999, The COSETI Observatory