On Sat, 16 Sep 2023, Ulrich Speidel via Starlink wrote:
On 15/09/2023 11:29 pm, Alexandre Petrescu via Starlink wrote:
I must say that I dont know whether the original 'DISHY' is simply a
dish antenna with an analog amplifier and maybe some mechanical motor
steering, or whether DISHY includes a computer to execute some protocol,
some algorithm.
In addition to that Ulrich says, the dishy is a full computer, it's output is
ethernet/IP and with some adapters or cable changes, you can plug it directly
into a router.
There are numberous teardown videos on youtube now, for both the original and
the 1st of the rectangular dishys, they will show you how complex the system is.
David Lang
>
It's a phased array, not a dish, even if it looks like one. It consists of
100's of fingernail-sized antenna elements that:
* during transmissions, have an individual phase delay added to the
signal transmitted from that element, in order to permit
transmission of the combined signal from all elements into a
particular direction.
* during reception, have an individual phase delay added to the signal
collected by that element, before the signals are added to obtain
the combined received signal. This allows reception from a
particular direction.
Dishy's main direction of transmission / reception is therefore not its
surface normal - this simply points to the area of the sky where Dishy
expects to see most satellites (a function of geographical latitude and
constellation design - essentially straight up in the tropics, and elsewhere
in the direction of the 53rd parallel, which corresponds to the predominant
orbital inclination in the Starlink fleet). The actual tracking is then done
with the phased array without mechanical movement by Dishy.
From what I've seen, Dishy seems to consume more power on receive than on
transmit - that's if you actually download stuff. This is somewhat
counter-intuitive if you're used to putting link budgets together. But I'd
attribute that to a higher degree of digital signal processing required on
the receive and demodulation path.
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