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Does anyone know why there is a giant pcb with an array of little chips on it? This is not a normal satellite dish. How does it work?

InitialLastName 5y ago
Looks like a phased array [0], which is probably a smart idea with a dish like that. Instead of using a parabolic reflector with a receiver at the focus (like in a normal satellite dish) they use an array of a ton of tiny receivers (each of those tiny ICs would be a driver for a small, on-PCB antenna). Phased arrays (essentially algorithmically delaying the individual radio signals from/to each driver on the scale of fractions of a period of the carrier frequency) let you do really precise beamforming and aiming, but take a lot of processing power and a lot of antennae to be efficient so weren't practical until recently. [0] https://en.wikipedia.org/wiki/Phased_array https://en.wikipedia.org/wiki/Phased_array
ChrisGammell 5y ago
It's a phased array, it uses those many little chips to do "beam steering". Check out this video by The Signal Path (a Bell Labs expert!) doing a teardown and explaning parts of it: https://www.youtube.com/watch?v=h6MfM8EFkGg https://www.youtube.com/watch?v=h6MfM8EFkGg
walrus01 5y ago
It is a phased array, the closest thing that exists to it in the rest of the world is the phased array radar in the nose radome of an air superiority fighter jet.
- apcragg 5y ago
  Phased arrays are everywhere. An incredibly common example are many cellular base station antennas. They are fancy but nothing particularly special these days. Active phased arrays, e.g. steerable with either analog phase / delay shifters or with digital front ends are less common but still much more common than the BAE Systems phased arrays in F35's.
  - mlindner 5y ago
    Starlink dishes are digital phased arrays, not analog.
    - apcragg 5y ago
      I'm pretty sure that it uses digitally controlled analog shifters. This is distinct from baseband IQ digital beamforming.
- tyingq 5y ago
  They are used for satellite based internet in commercial aircraft also.
- nitrogen 5y ago
  There are speaker companies that sell phased array loudspeakers for tuning the sound in e.g. a specific corner of a concert hall, where you can't just put extra speakers anywhere you want.
- bigiain 5y ago
  Isn't MIMO beam forming that modern wifi base stations use basically a phased array? I guess the Starlink dish's ~1200 antennas is way way closer to a fighter jet radar than it is to a six antenna Netlink wifi base station...

InitialLastName 5y ago

Looks like a phased array [0], which is probably a smart idea with a dish like that. Instead of using a parabolic reflector with a receiver at the focus (like in a normal satellite dish) they use an array of a ton of tiny receivers (each of those tiny ICs would be a driver for a small, on-PCB antenna). Phased arrays (essentially algorithmically delaying the individual radio signals from/to each driver on the scale of fractions of a period of the carrier frequency) let you do really precise beamforming and aiming, but take a lot of processing power and a lot of antennae to be efficient so weren't practical until recently. [0] https://en.wikipedia.org/wiki/Phased_array https://en.wikipedia.org/wiki/Phased_array

ChrisGammell 5y ago

It's a phased array, it uses those many little chips to do "beam steering". Check out this video by The Signal Path (a Bell Labs expert!) doing a teardown and explaning parts of it: https://www.youtube.com/watch?v=h6MfM8EFkGg https://www.youtube.com/watch?v=h6MfM8EFkGg

walrus01 5y ago

It is a phased array, the closest thing that exists to it in the rest of the world is the phased array radar in the nose radome of an air superiority fighter jet.

apcragg 5y ago
Phased arrays are everywhere. An incredibly common example are many cellular base station antennas. They are fancy but nothing particularly special these days. Active phased arrays, e.g. steerable with either analog phase / delay shifters or with digital front ends are less common but still much more common than the BAE Systems phased arrays in F35's.
- mlindner 5y ago
  Starlink dishes are digital phased arrays, not analog.
  - apcragg 5y ago
    I'm pretty sure that it uses digitally controlled analog shifters. This is distinct from baseband IQ digital beamforming.
tyingq 5y ago
They are used for satellite based internet in commercial aircraft also.
nitrogen 5y ago
There are speaker companies that sell phased array loudspeakers for tuning the sound in e.g. a specific corner of a concert hall, where you can't just put extra speakers anywhere you want.
bigiain 5y ago
Isn't MIMO beam forming that modern wifi base stations use basically a phased array? I guess the Starlink dish's ~1200 antennas is way way closer to a fighter jet radar than it is to a six antenna Netlink wifi base station...