What's funny is if you go sailing on the ocean for extended periods (months) you realize that sat data / phone costs are RIDICULOUS in this age. $3 - $5/MB. So your 4 GB movie is $20,000. You'd think, why would anyone pay this, but there can be a lot of pressure these days to be able to send videos etc so you sometimes get jammed up with these types of costs (ie, if you do a telemedicine call the DR may want a video of joint movement etc etc, recreational trips people want to post videos and don't realize their phone records at pretty large file sizes etc etc).
So if they can do better just on COST then this it would be wonderful.
At least V1 of Starlink, there needs to be a ground station visible to the satellite, so it's not going to work in the middle of the ocean.
It might work a few hundred miles offshore, but not further than that. So it'll be a while before you can have video calls from the middle of an Atlantic crossing.
> At least V1 of Starlink, there needs to be a ground station visible to the satellite
At an altitude of 340 miles a starlink satellite has line of site up to 1800 miles so conceivably a ship at sea could be 3600 miles from the nearest land station and still be able to bounce off Starlink. Of course that's ideal conditions, but it wouldn't take too many ground stations to ensure 99% of oceangoing traffic is covered.
Of course even with line of site, the antenna may not be oriented in such a way as to cover more than a couple hundred miles of surface even if there is line of site.
Even though the theoretical line of sight is 1800 miles, I expect that you'll get much less range. The satellites move very quickly— the satellite that's halfway between you and the ground station is very quickly going to be more than 1800 miles away from one of you. Transmitting signals at such oblique angles is also a lot harder. Part of it is just typical signal strength los due to r^2 law. But if you're transmitting thru that much atmosphere, you're going to experience a lot more interference from things like rain fade.
It just has to be above the horizon, because this is the middle of the ocean.
When I put 550km into a horizon calculator I get a distance of 2700km.
Edit: Okay, I want an explanation for the downvotes. If you're upset that I didn't say "the user terminal is horizontal at max range", I thought it was clear from context.
I didn't downvote you, but the size of the beam is heavily dictated by the elevation they're willing to work with, and the wider the elevation, the more expensive the antenna. So give that they need to decrease the size of the beam to keep antenna cost down, it's highly likely that the beam size is much, much smaller than what you cited there. Just take a look to see how many handoffs there are over CONUS alone: https://www.youtube.com/watch?v=m05abdGSOxY
We're talking about the user terminal, right? A ship can easily have a more expensive antenna array. Maybe even with a motor, or with three tilted in different directions.
> Just take a look to see how many handoffs there are over CONUS alone
That's just a simulation picking angles he thought looked good, in an area where there are plenty of options. It doesn't tell you anything about the limits of beam size, especially when there is no other sat in range.
Sure, ships can have more expensive antennas. But you need a lot of those ships out there and the antennas are extremely expensive. I'm not sure what you are arguing about the simulation. Are you saying it's inaccurate and there's a better one?
> Sure, ships can have more expensive antennas. But you need a lot of those ships out there and the antennas are extremely expensive.
We're talking about receiving internet on ships, right? You need one per ship that wants internet. And it doesn't have to be 'extremely' expensive, it could be a moderate multiple of the normal user terminal.
In case you forgot the context, this is not a conversation about using relays. This is a conversation about how far offshore you can go in a single bounce.
> I'm not sure what you are arguing about the simulation. Are you saying it's inaccurate and there's a better one?
It's perfectly fine, but the goal of that simulation is to show a way of doing long distance high speed relays. The goal is not to show you maximum range if you don't relay.
I'm talking about ships used for relay. Ships used for just internet over the water won't be possible if there are no gateways (other ships with relays) over the water. Those terminals do have to be expensive, just like the gateway ones, because the antenna performance is much higher than the user terminal's, and the radome is very large (see other pictures from reddit on here).
For the non-relay case, we've already established that due to beam size you can't get very far off shore before it won't work. The goal of the simulation was also to show beam size. If the beam sizes are arbitrarily large then obviously the simulation would have shown a single hop.
> I'm talking about ships used for relay. Ships used for just internet over the water won't be possible if there are no gateways (other ships with relays) over the water.
I figured that out, but that's not really what the conversation was about. If you add those gateways then you don't have the range problems, and this was a conversation about range problems.
> Those terminals do have to be expensive, just like the gateway ones, because the antenna performance is much higher than the user terminal's, and the radome is very large (see other pictures from reddit on here).
The video you linked talks about using normal user terminals as relays. A couple of those won't be full bandwidth, but your mid-ocean service wouldn't need to be full bandwidth.
If you're actually making a dedicated relay ship you'd probably want a full radome link, but only if it's cheaper than the ship you're putting it on. The limiting factor is the cost of the ships.
> The goal of the simulation was also to show beam size.
I strongly disagree. Beam size is modeled in a very simple way, because it's not the goal of the simulation. The goal is to show how links work in different ways, using normal-scope full-bandwidth service beams.
I strongly doubt that an almost-idle sat is unable to aim even a few degrees wider if they wanted to.
But the person making that sim would have no way to model that, and it's not really worth it to get an extra fraction of a millisecond. Better to make the simulation based on confirmed capability.
But for ships at sea it's not a fraction of a millisecond, it's the difference between connectivity and no connectivity. If ships at sea were starlink's primary customers then I bet they could and would get better range even with zero hardware changes.
> The video you linked talks about using normal user terminals as relays. A couple of those won't be full bandwidth, but your mid-ocean service wouldn't need to be full bandwidth.
If you see my comment and others, using user terminals as relays is going to be very difficult, if not impossible. The EIRP/GT of those terminals will likely be very low, and that single relay will cut the bandwidth significantly. They also have much lower availability than a gateway, which makes the routing decisions harder.
> I strongly disagree.
What beam size do you think they're using? It's not really a question of IF they want to. Doing so on a cheap terminal can easily break FCC interference guidelines due to sidelobes, thus making it not their decision. That's the reason why these systems design for a very specific elevation limit from the user side, because anything else would either have too poor performance at the detriment of the entire satellite, or it's illegal if you're transmitting where you shouldn't. The performance degradation is very serious as well. It can be as bad as a single user consuming 10x more satellite resources than a nominal user, just because they're outside of the coverage of the beam.
So I realize where you're coming from in that they can do it, but I guarantee given the link budgets and cost-benefit tradeoff, it's simply not worth it to cover that far off boresight.
This is clearly not representative of starlink, but rather a GEO constellation. But the same concept applies: they will have tiny 0dB contours, and it rapidly falls after that. Serving users outside of the main contours, while it might be feasible given their antennas, is a massive hit to capacity on the entire constellation.
By the way, I think this dialogue is good and neither of us are going to convince each other. I think we will have to wait and see a year from now and revisit these comments.
Are the FCC interference guidelines exactly the same in the middle of the ocean?
And for what it's worth I looked up one of the licensing sheets earlier and it talked about the allowed signal strength below 25 degrees tapering off by 15dB. That's not enough to stop you from having a signal.
> too poor performance at the detriment of the entire satellite
> Serving users outside of the main contours, while it might be feasible given their antennas, is a massive hit to capacity on the entire constellation.
I think you're agreeing with me here.
It might cost a lot of the satellite's performance, which is why you wouldn't do it over land, and why it would be even less reasonable to include it in the simple simulation you linked.
But satellites over the ocean have nothing better to do with most of their capacity.
> By the way, I think this dialogue is good and neither of us are going to convince each other. I think we will have to wait and see a year from now and revisit these comments.
I'm fine stopping here, but revisiting in a year probably wouldn't help. There is a huge difference between what they can do, and what they care enough to do. Servicing ships that are more than 300 miles offshore, but not too much more, is definitely not a priority.
But you can bounce it off "ground" stations sitting in the ocean. For instance on barges and islands, or just on other customers ships. It doesn't take that many ground stations to be able to be routed to land. Or from land on one side of the ocean to the other.
Is there a rough v1/v2 timeline? The thing they wanted to release by the end of the year is v1 I assume?
Is v2 just a software update? Does it require sending a whole new set of satellite or it something they are planning to patch into existing satellites someday and have inter-sat support?
The original plan required a laser link, but those were removed from the v1 satellite because the lasers would survive reentry and SpaceX didn't want their satellites falling on anybody's head. So this is definitely a hardware upgrade requiring new satellites.
But that's not a big stumbling block -- SpaceX plans on replacing 1/5th of their constellation every year.
That’s kind of a moot point as SpaceX is not going to put satellites over the Atlantic without that capability or even build out their network. Everything is still very much in testing phases right now.
None of these satellites are anywhere near geosynchronous orbit so every satellite circles the globe. They don't really get much of a choice as to where to put them other than altitude and inclination. The satellites are in different orbital planes but that plane rotates with respect to the earth so there's no getting around the majority of satellites sitting out over the oceans.
To be clear, I am saying their plan is so have the links up before the consolation is finished. These early launches are going to be in a higher orbit which will allow them to offer the service on land before the full constellation is finished as well as provide redundancy.
We used a sat link for getting the latest weather information, though you can also get that frequently on V(HF), so .. not terribly useful. But, terribly slow and unreliable (Iridium).
So if they can do better just on COST then this it would be wonderful.