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How far it is possible to communicate ?

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How far it is possible to communicate ?
3rd Jun, 2017 at 7:48am
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Have you ever wondered how far it is possible to communicate ?

If so, try experimenting with my range calculator at SETI range calculator

Tell us what result you get.

Best regards, Eric
  

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Re: How far it is possible to communicate ?
Reply #1 - 26th Jun, 2017 at 3:59pm
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Here is a list of possible nearby stars with planets that are vaguely habitable and thus might have aliens living there, together with list of the distances in light years.

O'Leaf(Watts) Centauri b   4.22
GJ 273b Luyten's Star     12.36
Kapteyn b*                13
Wolf 1061c                13.8
Gliese 667 Cc             23.62

TRAPPIST-1e               39
TRAPPIST-1f               39
TRAPPIST-1g               39
Tau Ceti e*               12

Gliese 832 c              16
Gliese 682 c              17
HD20794 e?*               20
Gliese 625 b              21.3

Gliese 180 c              38
Gliese 180 b              38
LHS 1140 b                40
Gliese 422 b*             41

HD 40307 g                42
Gliese 163 c              49
Gliese 3293 c             59


More details here:
https://en.wikipedia.org/wiki/List_of_potentially_habitable_exoplanets
  

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Re: How far it is possible to communicate ?
Reply #2 - 9th Jul, 2017 at 5:30pm
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There is a project idea to send a probe called Icarus to Alpha Centauri and I've just read about it in the British Interplanetary Society magazine, Aug 2017.  There was a bigger article in their Journal Vol 69, pages 278-288, 2016, but I don't have that.

It contemplates a downlink bit rate of 20 Gbit/s of information from Alpha Centauri at over 4 light years away using speculative antennas 1 km diameter and 15 km diameter at 32 GHz.

I've done a link budget here http://www.satsig.net/seti/talking-to-icarus.htm

Comments welcome.

Eric
  

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Re: How far it is possible to communicate ?
Reply #3 - 18th Jul, 2017 at 4:42pm
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I think, the RF may be in THZ range instead of 30 Ghz. In that case, the antenna diameter may be smaller. I have no idea whether that frequency is possible !
  
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Re: How to calculate SETI range ?
Reply #4 - 15th Dec, 2017 at 7:32pm
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I am having an interesting email debate about how to calculate the range of SETI detection.

References:
http://www.satsig.net/seticalc.htm
https://www.pasternack.com/t-calculator-fspl.aspx

Extract..

I think I have found the problem with the differences.

My definition of path loss involves only range and frequency.
Normally I use :

function pathloss(range, freq) { 
// range in km, freq in GHz 
a=92.45+20.0*Math.log(range)/Math.log(10.0)+20.0*Math.log(freq)/Math.log(10.0); 

return a; 
}

This one: https://www.pasternack.com/t-calculator-fspl.aspx includes the gains of both antennas.

My web page http://www.satsig.net/seticalc.htm does not work out the path loss by either formula.  It attempts to work backwards to find the range as the answer to the process, like so:

function pathloss(eirp,cn,gont,bw) { 
// eirp in dBW, cn = carrier to noise, gont=rx g/t, bw=bandwidth Hz 
a=eirp-cn+1.0*gont-10.0*Math.log(bw)/Math.log(10.0)+228.6; 
return a; 


If anyone else wants to add their help please do so or email me eric@satsig.net
  

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