Quote from: vsatman on 02/09/2022 06:50 pm3) The comment thread is dedicated specifically to the feeder link, since I have seen in Internet the statements of individual commentators that StarLink uses 2 feeder lines at the same time, each of the 2 antennas with its own gateway, which I consider impossible.The only reason you gave to support this being impossible was the need to do handoffs. Which isn't actually a reason, as the user link also needs to do handoffs, and these can coincide. With multiple satellites always visible to every user, they don't need continuous uptime on every satellite. Giving up 1 second or so of transmit time every minute in order to double the uplink throughput is a huge overall increase.
3) The comment thread is dedicated specifically to the feeder link, since I have seen in Internet the statements of individual commentators that StarLink uses 2 feeder lines at the same time, each of the 2 antennas with its own gateway, which I consider impossible.
well, let's analyze it separately Each StarLink satellite changes its gateway at least once every 2...4 minutes 10 seconds (max time). In order to change the gateway, the Ka-band antenna on sat must turn back up to 130 degrees.
Have you ever seen how a SeaTel or Intellian marine antenna is tuned? How many time they need to turn? (in seconds?) Please "quickly" is not answer , Answer is X seconds..
After prime pointing "in direction" , if it receives the signal from the beacon on GW begin precise pointing both (!!!) Antennas - on Sat and on GW. After that, as fine pointing is completed, the Antenna and link Sat-GW 2 is ready for operation with nesessary SNR, server on the gateway can send a message to the NMС that GW2 is ready to serve satellite X and the corresponding cells NN was served from Gateway 1, now it must be served by Gateway 2. At the same time, the NMS should redirect traffic for users from POP 1 to which GW1 is connected to POP2 to which GW2 is connected ..And only after all these processes are implemented, the operating configuration of the full StarLink Network "Gateway - satellite- cell" for the next 15 seconds is created, service through the gateway 2 can begin. A temporary break for these processes is at least 15 seconds, and maybe more.(I would personally take an additional 15 seconds as a margin of time so that if it is not possible to сonnect to GW2. will be time to switch to GW3)
That is why OneWEB Engineers (who created early O3B NGSO Network) have chosen the method described above to ensure the 100% continuity of the service.
If the Space X Engineer believed that it was permissible to interrupt the service for the user every 4 minutes for 15-30 seconds per, they would have been fired on the same day.
And I am happy to read any SpaceX document that can confirm your words each Sat will be served from 2 GW in one moment.
P.S. I have a question Have you ever worked in Telecom in the field of service quality? or Satellite Networks?What service availability should StarLink provide in your opinion?
//Second, while I have not worked out the math for Starlink, LEO satellites can easily have 15-20 minute downlink windows, so 2-4 minutes should not be typical.So can you calculate first? and then you will write nonsense about 15-20 minutes for StarLink?//to calling the SpaceX engineers idiots.This is a good point. So we have 2 options for organizing a feeder channel with a speed of 20 Gbps. Option A Proven many times, as OneWeb engineers did. to use one feeder channel at a time from a single 1.5m antenna on the Gateway with a maximum throughput of 32 Gb and a typical 25+ GbpsOption B, which, according to your words, was implemented by SpaceX engineers - use simultaneously 2 feeder lines and 2 Antennas on different gateways, each with a maximum capacity of 32 Gbps and a typical 25+ Gbps. In total, they transmit either 25 or 50 Gbps to the satellite, although 20 gbps are needed. At the same time, there is some kind of magic box on the satellite for redistributing traffic at the packet level on board (a task that no manufacturer in the world has solved so far for a serial satellite ). Naturally, this unique magic box increases the cost of the satellite, requires additional power, and reduces the reliability of the satellite. At the same time, no one knows about the magic box yet, and there is no mention in any SpaceX document, although its appearance would be a sensation and an achievement much greater than laser channels.From my point of view, the Engineer who proposed option B instead of A can be called an idiot. But note that you called SpaceX engineers idiots, not me ..
from multiple aerial photos the starlink base stations have 9 domed steerable parabolic dishes in a 3x3 grid
At the same time, there is some kind of magic box on the satellite for redistributing traffic at the packet level on board (a task that no manufacturer in the world has solved so far for a serial satellite ).
Quote from: SpaceCadet1980 on 02/10/2022 07:00 pm//Second, while I have not worked out the math for Starlink, LEO satellites can easily have 15-20 minute downlink windows, so 2-4 minutes should not be typical.So can you calculate first? and then you will write nonsense about 15-20 minutes for StarLink?
//Second, while I have not worked out the math for Starlink, LEO satellites can easily have 15-20 minute downlink windows, so 2-4 minutes should not be typical.
//to calling the SpaceX engineers idiots.This is a good point. So we have 2 options for organizing a feeder channel with a speed of 20 Gbps.
From my point of view, the Engineer who proposed option B instead of A can be called an idiot. But note that you called SpaceX engineers idiots, not me ..
Quote from: vsatman on 02/11/2022 06:29 amSo can you calculate first? and then you will write nonsense about 15-20 minutes for StarLink?You are the one who made up a number based on nothing. I gave a number based on experience working LEO satellites. You can either choose to learn something about the subject and do the math yourself, or you can stop making baseless assertions.
So can you calculate first? and then you will write nonsense about 15-20 minutes for StarLink?
Quote from: SpaceCadet1980 on 02/11/2022 05:23 pmQuote from: vsatman on 02/11/2022 06:29 amSo can you calculate first? and then you will write nonsense about 15-20 minutes for StarLink?You are the one who made up a number based on nothing. I gave a number based on experience working LEO satellites. You can either choose to learn something about the subject and do the math yourself, or you can stop making baseless assertions.Oh, let's analyze this nonsense, so the 2 most banal questions:1) What is the orbital period of the StarLink Satellite around the Earth?2) What is the diameter of the circle in the sky that the gateway antenna sees?Anyone with even the slightest interest in StarLink should know these numbers. Next 2 calculations at the elementary school level.a great way to understand what is behind your words and what is your real experience in satellite communications :-), and is there any point in reading further everything that you write ..[zubenelgenubi: Fixed quotes. Please proofread your reply posts before posting.]