Re: [Starlink] Measuring a Low-Earth-Orbit Satellite Network

[Alexandre Petrescu <alexandre.petrescu@gmail.com>]

Le 15/09/2023 à 20:03, Dave Taht a écrit :
> 
> 
> On Fri, Sep 15, 2023 at 3:58 AM Alexandre Petrescu via Starlink 
> <starlink@lists.bufferbloat.net
> <mailto:starlink@lists.bufferbloat.net>> wrote:
> 
> 
> Le 17/08/2023 à 18:42, Dave Taht via Starlink a écrit :
>> On Thu, Aug 17, 2023 at 7:47 AM Dave Taht <dave.taht@gmail.com
> <mailto:dave.taht@gmail.com>> wrote:
>>> This paper, at first glance, looks really, really good,
>>> measuring detailed topology of the starlink network: 
>>> https://arxiv.org/abs/2307.06863
>>> <https://arxiv.org/abs/2307.06863>
>>> 
>>> Thank you J Pan for passing it along!
>> More recent data here:
>> 
> https://www.reddit.com/r/StarlinkEngineering/comments/15p76j4/impressive_improvement_in_three_months_no_longer/
> <https://www.reddit.com/r/StarlinkEngineering/comments/15p76j4/impressive_improvement_in_three_months_no_longer/>
>
>  Sorry but I do not understand the graphs.  The URL sounds great.
> 
> 
> I have cc´d the author.
> 
> For my part, I can tell that I follow one particular sat chosen 
> arbitrarily (STARLINK-6064) on a public database since some weeks
> now and it keeps at around 360km altitude.   That is much lower than 
> 500-or-so usual.  Maybe it is that lower altitude that permits a
> higher performance (lower latencies).
> 
> 
> Pretty neat!
> 
> 
> (there are other sats even lower, but not sure whether they're there
> in error or on their way up).
> 
> 
> this was really good: 
> https://radionavlab.ae.utexas.edu/wp-content/uploads/2023/01/starlink_structure.pdf
> <https://radionavlab.ae.utexas.edu/wp-content/uploads/2023/01/starlink_structure.pdf>

The
> 
paper is interesting.  The authors built a system to listen to
starlink.  That is a valuable effort.

It would be interesting to know in a public way what are precisely the
freqs used by starlink DISHYs.

This paper seems to be saying it is listening on: 10.7–11.7 GHz (the
lower band) and 11.7–12.75 GHz (the upper band).

However, this other paper from ETSI, cited on this email list, seems to
be saying: Receive (space-to-Earth) 10,70 GHz to 12,75 GHz, Transmit
(Earth-to-space) 14,0 GHz to 14,50 GHz.  Remark the differences between
the two.
https://www.etsi.org/deliver/etsi_en/303900_303999/303981/01.02.00_30/en_303981v010200v.pdf

I am not sure which of the two to trust, should only one be the right
one, or both.

It could be, for example, that the UT authors listen to something, hear
something, but not sure whether that is the starlink they hear.  It
could be too that the ETSI document being respected by starlink is just
a supposition.

Maybe an additional, more authoritative, source of info is to list out
the freqs reserved by starlink at FCC and other regulators.  Maybe the
DISHY and the user manual also has some labels telling precisely which
are the frequencies.

It is not clear to me whether a freq allocated by FCC in USA for
starlink is also allocated in Europe.

There are a number of freqs proposed for allocation in Europe for
constellations, yet they differ even between two EU countries, so.

Alex

> 
> Getting more correlated results from two or more stations in the same
>  cell would help.
> 
> 
> Alex
> 
>> 
>>> 
>>> ---------- Forwarded message --------- From: J Pan <Pan@uvic.ca
>>> <mailto:Pan@uvic.ca>> Date: Wed, Aug 16, 2023 at 11:02 PM 
>>> Subject: starlink To: dave.taht@gmail.com
>>> <mailto:dave.taht@gmail.com>
> <dave.taht@gmail.com <mailto:dave.taht@gmail.com>>
>>> 
>>> 
>>> Hi Dave: thanks for your libreqos work. did you see 
>>> https://arxiv.org/abs/2307.06863
> <https://arxiv.org/abs/2307.06863> ? cheers.  -j
>>> -- J Pan, UVic CSc, ECS566, 250-472-5796 (NO VM), Pan@UVic.CA,
> Web.UVic.CA/~pan <http://Web.UVic.CA/~pan>
>>> 
>>> 
>>> -- Podcast: https://www.youtube.com/watch?v=bxmoBr4cBKg
> <https://www.youtube.com/watch?v=bxmoBr4cBKg>
>>> Dave Täht CSO, LibreQos
>> 
>> 
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> 
> -- Oct 30: 
> https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
>  
> <https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html>
>
> 
Dave Täht CSO, LibreQos