david@djwhome.demon.co.uk (David Woolley) wrote in message > 

Thanks for your response, David.
Everything you said makes a lot of sense.

The strength of the signal was determined by the primary purpose of the
transmitter, which is planetary radar, i.e. getting reflections from
within the solar system.  Even the modern version of that radar is very
much at its limits at Jupiter, so, especially as radar signal returns
fall off as the fourth power of distance.   It's limit is 10s of light
minutes not well over a light year.

I think I remember seeing Arecibo returns from one of Saturn's moons a
few years ago.

Are you saying that the Arecibo Shout signal was not of exceptional
intensity - just an "ordinary" narrow beam planetary radar
transmission?

From the previous 5 year anniversary of the Shout Signal:
http://www.news.cornell.edu/releases/Nov99/Arecibo.message.ws.html

Regards,
Craig

PS:
This isn't the reference I remember, but here's a link to news about
Arecibo radar returns from Titan:
http://www.news.cornell.edu/releases/Oct03/Titan.Campbell.bpf.html