I know this has been discussed before but I would like to refine this a bit more.

Let make a few assumptions.

Lets assume there is a planet that orbits one of closest stars (Aplha Centauri) and that the aliens that inhabit it call the planet AC, they think it is a cool name. We will need to make a few more assumptions for the sake of this question. One is they are at the exact same advancement in science and tech as we are and not only that they have a program also that is looking for alien signals in the exact manner as Seti@home is. Of course most of you know where this is heading but I am going to finish it anyways.

Would they be able to detect us? If they also have been sending radio noise out into space for 70 plus years, could we detect them? I know we are looking for consistent chirping. would our signals be strong enough to pick them up or would one of us have to direct a strong signal and broadcast it towards them with the hope that they would then detect it?

Other comments or additional questions that keep to the topic are encouraged. There is always the thought in the back of ones mind that wonders if we are searching in the best manner.

Thank you
Bob

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Sometimes I wonder, what happened to all the people I gave directions to?
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SETI@home classic workunits 4,321
SETI@home classic CPU time 22,169 hours

I would tend to say yes. They would probably pick up our most powerfull transmissions easy but this
is all just maths and physics. Lets assume they and we stop to rotate when both our Aracibos are facing
each other perfectly.

How much ERP (effective radiated power) would be needed at the transmitting ''Aracibo''
(knowing that the signal has 4 light years to cross and that it will fade to the square of the distance)
for the signal to get at the receving ''Aracibo'' with enough energy so it has an S/N (signal to noise) ratio
good enough so it can be detected ?

You have all the the info to make a quick estimate.
- The intensity the signal need to have at the receiving end in order to be detected.
- The receiver sensitivity, the antanna gain (very high) and the noise level.
- the distance.
From there you know how much ERP is needed at the transmitting ''Aracibo'' and since you know the
antenna gain you know how much RF power you need.

Its just a guess but in CW mode (continious wave) at 1.2GHz and with the perfect conditions of having
both antennas facing each other two radio operators could have a morse code converstation with no more
then a 1KW transmitter (MW ERP). And a lots of patience....

This thread and Seti@home is not about communicating, I completely agree with you that is would very doable even without using 2 huge dishes on both ends. Right now SETI is all about detecting, I assume communication with any alien source would go to some other project.

Lets get back to the topic at hand, Do we leak enough signal and strength to create persistent and delectable chirps 4 LY away with the equipment and software we are using. You mentioned

but this all just maths and physics

and if the signal acts like gravity and fades the square of the distance, will it still be delectable at that distance?

We are trying to detect some signal or communication from a alien source without having much of an idea of how they would communicate. A sample size of one does not help us a lot in knowing how communication develops with civilizations. Questioning methodology is a good way to help develop it.

Thank you
Bob

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Sometimes I wonder, what happened to all the people I gave directions to?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SETI@home classic workunits 4,321
SETI@home classic CPU time 22,169 hours

From 49:30 to 50:22
https://www.youtube.com/watch?v=vQ2sKwwhRgI

Oh

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What I suspected. At this time we would only detect a high energy signal that was sent in our direction or close to it even with sun that are close to us.

I am not saying what we are doing is not worth while. There is a small chance to catch or detect a directed signal. The other important aspect of this project is that we need to find out what works in order to know what will work. Most successes are built on many attempts. Some attempts will have more success that others of course.

I think we have a ways to go before we can say we hit our Kitty Hawk moment and even have done a short flight. Extremely difficult to know what may work when you only have a sample size of one.

Thanx
Bob

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Sometimes I wonder, what happened to all the people I gave directions to?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SETI@home classic workunits 4,321
SETI@home classic CPU time 22,169 hours