On 1-4-2010 8:56, scott wrote:
>> 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? 

I don't know.

> 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.  

The SETI equipment might even be somewhat more sensitive because they 
are using larger disks. Then again they don't know what exact frequency 
to tune into.

BTW I arrive at something more like 47 MW if the voyager is transmitting 
all its power, which is unlikely, so the number could even be much lower.


> Is that realistic to expect?

If you really want to broadcast a message anything is realistic.

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