From: David M. Ocame (n1yvv@hotmail.com)
Date: Fri Aug 16 2002 - 21:25:20 PDT
Ok, I'm a bit at a loss for understanding this thread. Larry raises a valid point, I think. We have discussed the possibility of receiving planetary radar of other ETCs. We're just doing the reverse and wondering who might be on the receiving end.
Do I have this right?
Dave Ocame
----- Original Message -----
From: LARRY KLAES
To: setipublic
Cc: BioAstro
Sent: Friday, August 16, 2002 11:41 PM
Subject: SETI bioastro: Re: Arecibo is sending out planetary defence radar, 900kilo watts.
The concept of picking up radar signals from ETI tracking
planetoids and comets in their own star systems has been
discussed before:
http://www.coseti.org/2704-22.htm
Larry
----- Original Message -----
From: David Woolley
Sent: Friday, August 16, 2002 2:59 AM
To: public@setileague.org
Subject: Re: SETI public: Arecibo is sending out planetary defence radar, 900kilo watts.
> Actually I was thinking of any civilizations that might be on
> the opposite end of the radio beams - you know, the guys
> we are searching for. :^)
These transmissions are quite regular, and one of the reasons why
Arecibo was built. In fact, it was an earlier, lower power, version
of the same transmitter that was used for the original Arecibo
active SETI message.
They are much more likely to be detected than the official message, as
their total power on time is much higher and because about 50% of them
are pure (doppler corrected for the target) CW. The rest are bi-phase
modulated pseudo random bit sequences. Typically local targets are
first illuminated with CW and then followed up with ranging codes, but
distant targets are only illuminated with CW.
The main problem for SETI is that they are one time events, and for
near earth objects, the beam will be panning relatively fast.
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