> The major things we have been sending is FM (and AM) modulated radio and 
> TV. This is effectively a big signal in a very small bandwidth. If you 
> make a spectrum it will turn up as an unexpected peak above the 
> background. If you then become interested and look closer you will see 
> that the spectral contend is not compatible with a line originating from 
> an exited atom or molecule. So, if these aliens are at the right time and 
> place and have a SETI project running they will detect us in a couple of 
> centuries when the signal reaches them.

OOC how sensitive is the SETI equipment and project?  I mean how big must a 
signal be from 200 ly away that we are able to detect it with that system? 
Extrapolating from the Voyager power levels and distance, I make it that we 
need a 350 GW signal to be transmitted from 200 ly away.  Is that realistic 
to expect?

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