4 ms·

this is completely incorrect. viasat's technology is far more advanced than starlink. just because it's not LEO doesn't mean it's simple. and starlink doesn't

this is completely incorrect. viasat's technology is far more advanced than starlink. just because it's not LEO doesn't mean it's simple. and starlink doesn't have dramatically increased capacity. they have a moderate increase over the busy areas geo incumbents have. most of their capacity is over water.

walrus01 4y ago
The end results of the link budgets required for geostationary to low cost consumer grade terminals means that now matter how good viasat's tech is, the end result is going to be mediocre. Have you actually lived on the far end of a consumer grade highly contended oversubscribed ku/ka band vsat terminal? Viasat's modems and rf chain stuff are about as good as can be expected within the very constrained BOM budget, antenna gains and link budgets involved.
- shaklee3 4y ago
  I've had their service for 4 years straight in the past. it's not as good as cable, but it's nowhere near as bad as you say if you're not playing real time games. the constrained BOM is the very reason why the terminal cost is reasonable for this business. it's well known that SpaceX is selling the terminal at a huge loss to gather customers in the short term.
  - walrus01 4y ago
    Even if viasat's consumer service was handing out high quality steel 1.8 meter elliptical offset ku band dishes with norsat PLL LNBs and 8W BUCs to consumers, the path loss and modulations required would mean that a given section of contended (let's say, 10MHz of a transponder) service to many terminals would still have significantly lower speeds and greater oversubscription to be economically viable compared to what end users see right now on starlink.
    - shaklee3 4y ago
      that's simply not true. they have transponders that should deliver 10Gbps to a single user IF they were willing to pay for both the service and terminal. SpaceX is limited in the exact same way, and their terminals + satellite costs are much higher for the number of them.
      - walrus01 4y ago
        10Gbps to a single terminal using exactly what modulation and code rate, and channel size? Or course you can achieve high speeds over geostationary if you throw entire transponders full of MHz at the problem. Which has a proportionally huge monthly recurring cost to control that transponder space. Or as a total percentage of the satellite's transponders dedicated to your network. Yes satellite tx power from the twta is more powerful than it used to be. You still need a huge ass earth station to start doing 16apsk/32apsk reliably.
        shaklee3 4y ago
        I'm not sure what point you're trying to make here. starlink is also multiple smaller beams within a single beam for frequency reuse. a single beam does not get more bandwidth (in Gbps) than a viasat terminal. > You still need a huge ass earth station to start doing 16apsk/32apsk reliably. 16apsk has been used for about a decade now on GEO satellites. I'm not sure why the gateway size matters when we're talking about user speeds.
        walrus01 4y ago
        If you don't understand why in a geostationary based link, the antenna size at either end matters a great deal for overall link budget, gain, Eb/No and what modulation you can use at a certain MCS and code rate before it gets too blurry in a QAM eyeball chart, there's no sense in talking about satellite communications with you. I note you didn't answer my question because you have no idea of what modulations, channel size and such are required to actually push 10Gbps through a satellite link to a single terminal. I think you're going off Viasat's marketing material where they're claiming aggregate throughput of an entire satellite or something. Show me the exact hardware configuration of modems you think are capable of 10Gbps by geostationary and how much transponder MHz it needs.

walrus01 4y ago

The end results of the link budgets required for geostationary to low cost consumer grade terminals means that now matter how good viasat's tech is, the end result is going to be mediocre. Have you actually lived on the far end of a consumer grade highly contended oversubscribed ku/ka band vsat terminal? Viasat's modems and rf chain stuff are about as good as can be expected within the very constrained BOM budget, antenna gains and link budgets involved.

shaklee3 4y ago
I've had their service for 4 years straight in the past. it's not as good as cable, but it's nowhere near as bad as you say if you're not playing real time games. the constrained BOM is the very reason why the terminal cost is reasonable for this business. it's well known that SpaceX is selling the terminal at a huge loss to gather customers in the short term.
- walrus01 4y ago
  Even if viasat's consumer service was handing out high quality steel 1.8 meter elliptical offset ku band dishes with norsat PLL LNBs and 8W BUCs to consumers, the path loss and modulations required would mean that a given section of contended (let's say, 10MHz of a transponder) service to many terminals would still have significantly lower speeds and greater oversubscription to be economically viable compared to what end users see right now on starlink.
  - shaklee3 4y ago
    that's simply not true. they have transponders that should deliver 10Gbps to a single user IF they were willing to pay for both the service and terminal. SpaceX is limited in the exact same way, and their terminals + satellite costs are much higher for the number of them.
    - walrus01 4y ago
      10Gbps to a single terminal using exactly what modulation and code rate, and channel size? Or course you can achieve high speeds over geostationary if you throw entire transponders full of MHz at the problem. Which has a proportionally huge monthly recurring cost to control that transponder space. Or as a total percentage of the satellite's transponders dedicated to your network. Yes satellite tx power from the twta is more powerful than it used to be. You still need a huge ass earth station to start doing 16apsk/32apsk reliably.
      - shaklee3 4y ago
        I'm not sure what point you're trying to make here. starlink is also multiple smaller beams within a single beam for frequency reuse. a single beam does not get more bandwidth (in Gbps) than a viasat terminal. > You still need a huge ass earth station to start doing 16apsk/32apsk reliably. 16apsk has been used for about a decade now on GEO satellites. I'm not sure why the gateway size matters when we're talking about user speeds.
        walrus01 4y ago
        If you don't understand why in a geostationary based link, the antenna size at either end matters a great deal for overall link budget, gain, Eb/No and what modulation you can use at a certain MCS and code rate before it gets too blurry in a QAM eyeball chart, there's no sense in talking about satellite communications with you. I note you didn't answer my question because you have no idea of what modulations, channel size and such are required to actually push 10Gbps through a satellite link to a single terminal. I think you're going off Viasat's marketing material where they're claiming aggregate throughput of an entire satellite or something. Show me the exact hardware configuration of modems you think are capable of 10Gbps by geostationary and how much transponder MHz it needs.