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<p>Did you mean to say 20 km diameter or 20 km^2 area?<br>
</p>
<p>For those not familiar with RF engineering terms: A 3 dB contour
as Oleg shows it below in blue is the line where the power flux
density from the satellite drops to half of the value at the
centre of the beam. That's important as in RF engineering of
cellular or beam division networks, the minimum power you need to
receive a signal successfully can be several orders of magnitude
larger than the amount of power you need to cause interference to
off-beam unintended receivers. So in terms of their interference
contour, beams are actually much wider than just a cell or so, and
a power flux density half as high as at beam centre doesn't mean
that it's the perimeter of the beam as such - the beam will
happily interfere with anyone up to a few cells down the road at
least. <br>
</p>
<p>Incidentally, I'm seeing Dishy use more power when it's receiving
at higher rates, which is what you'd expect if its DSP is busy
digging out intended signals from unintended ones.<br>
</p>
<div class="moz-cite-prefix">On 24/02/2023 1:18 pm, Oleg Kutkov via
Starlink wrote:<br>
</div>
<blockquote type="cite" cite="mid:9dd258eb-1bdb-4234-1301-744ee77b4097@olegkutkov.me">
<p>Yes. The cell size is ~20 km</p>
<p><img src="cid:part1.FBWhLdO6.cwK09S3X@auckland.ac.nz" alt="" class="" width="320" height="240"></p>
<div class="moz-cite-prefix">On 2/24/23 02:08, David Lang wrote:<br>
</div>
<blockquote type="cite" cite="mid:q61966n4-ns93-25qn-899o-3r8os67q7qos@ynat.uz">they can
only narrow the radio beam so much (probably whatever their cell
size is). They can't change the footprint without changing the
antenna, so unless they have the beam move around in the cell,
the footprint should be slightly larger than the cell size <br>
<br>
sometimes there is a lot of data going to one station, but
sometims it's only going to be a trival amount (think ack
packets for a lot of uploads), so they can save airtime by using
one timeslot to transmit to many stations at once. <br>
<br>
David Lang <br>
<br>
On Fri, 24 Feb 2023, Oleg Kutkov via Starlink wrote: <br>
<br>
<blockquote type="cite">Date: Fri, 24 Feb 2023 01:47:05 +0200 <br>
From: Oleg Kutkov via Starlink <a class="moz-txt-link-rfc2396E" href="mailto:starlink@lists.bufferbloat.net" moz-do-not-send="true"><starlink@lists.bufferbloat.net></a>
<br>
Reply-To: Oleg Kutkov <a class="moz-txt-link-rfc2396E" href="mailto:contact@olegkutkov.me" moz-do-not-send="true"><contact@olegkutkov.me></a>
<br>
To: <a class="moz-txt-link-abbreviated moz-txt-link-freetext" href="mailto:starlink@lists.bufferbloat.net" moz-do-not-send="true">starlink@lists.bufferbloat.net</a> <br>
Subject: Re: [Starlink] System and method of providing a
medium access control <br>
scheduler <br>
<br>
Oh, that's interesting. <br>
<br>
>> the satellite broadcasts the downlink radio frame to
all the user terminals in a group and they each retrieve their
respective data from the downlink radio frame <br>
<br>
I thought the satellite beamformer only sends data frames to
the appropriate UT. It looks like the given satellite covers
the whole cell at one TX channel. <br>
Otherwise, it would be too complex, I guess. <br>
<br>
On 2/23/23 23:53, Dave Taht via Starlink wrote: <br>
<blockquote type="cite">For those of you that don't look at
patents, don't look at: <br>
<br>
<a class="moz-txt-link-freetext" href="https://patents.justia.com/patent/11540301" moz-do-not-send="true">https://patents.justia.com/patent/11540301</a>
<br>
<br>
But I would welcome comment from those that do. <br>
<br>
H/T virtuallynathan. <br>
<br>
</blockquote>
<br>
</blockquote>
</blockquote>
<pre class="moz-signature" cols="72">--
Best regards,
Oleg Kutkov</pre>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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</blockquote>
<pre class="moz-signature" cols="72">--
****************************************************************
Dr. Ulrich Speidel
School of Computer Science
Room 303S.594 (City Campus)
The University of Auckland
<a class="moz-txt-link-abbreviated" href="mailto:u.speidel@auckland.ac.nz">u.speidel@auckland.ac.nz</a>
<a class="moz-txt-link-freetext" href="http://www.cs.auckland.ac.nz/~ulrich/">http://www.cs.auckland.ac.nz/~ulrich/</a>
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