Acquisition Signal (Signpost SETI)

9010-016

This diagram illustrates the idea of having a strong "Signpost" beacon signal at one frequency and the weaker wideband "Main Signal" at another.

It is more likely that the beacon or acquisition signal would be adjacent to the wideband data signal or even part of it. That is why, the COSETI Observatory is looking for "the lighthouse in the sky" beacon in the optical spectrum, where it is expected the wideband signal would be co-located. It is very difficult if not impossible to transmit a wideband signal over interstellar distances due to interstellar dispersion and scintillation effects.

Copyright (c), 1990, The COSETI Observatory