Some Views on Satellite Communications

Original link: https://mabbs.github.io/2023/09/06/satellite.html

Satellite communications may not be difficult ?

cause

Some time ago, Huawei released a mobile phone that can make satellite calls – Mate 60 Pro. Although I am not very interested in Huawei, and I am not interested in its marketing level of selling chips 3 years ago to 7K+CNY, but I am still very interested in satellite communications, so today I want to talk about what I know Got something about satellite communications.

About Satellite Communications

In fact, satellite communication is very common around us. The most common one is GNSS. Now not only mobile phones can navigate through satellites, but also various Internet of Things devices. However, this is still a bit different from satellite phones, because satellite phones are two-way communication, but navigation satellites are one-way communication. The mobile phone calculates the current coordinates through the position information broadcast by satellites and some signal differences, so connecting to navigation satellites is not necessary. A very long antenna is needed because it doesn’t need to transmit a signal.

Similar to this is satellite TV. Although satellite TV does not require two-way communication, it may be because of its relatively large bandwidth and high stability requirements? So most of them need a receiving pot to receive satellite signals. But maybe what I said is wrong. In the past, when smartphones were not very popular, there was a kind of satellite TV that could be watched on small devices called CMMB. That was to pull out an antenna on the phone to watch TV, but I Not sure if this one works via satellite or via terrestrial relay, maybe both? I remember it seems to be able to receive the signal in the room, not sure if this small antenna can actually connect to the satellite.

In addition to these, there are some people who do ham radio and the like can send pictures from space through SSTV or something like that, but I don’t know much about these ? , not much to say.

As for the two-way communication, there may be relatively few encounters in daily life. It may be more common that some TV stations use satellites to transmit signals and the like, and it seems that international long-distance calls are also transmitted through satellites. Of course, the devices that do these operations generally have very large antennas.

Smaller ones are not unavailable. Some more advanced cars will be equipped with on-board satellite phones, which can be used in emergency rescue. Of course, ordinary satellite phones are not big, but they usually have folding antennas, and the price is not bad. , There are more than 2K cheap ones. In addition to satellite phones, the most famous one is Starlink, which also uses satellite pots to access the Internet, but because it is a near-Earth satellite and there are a large number of them, the speed is much faster than that of communication satellites.

In addition, I have seen a big guy use satellites to communicate with people all over the world , but the antenna is relatively large and has to be operated manually ? .

Opinions about Huawei Satellite Phone

To sum up, it seems that Huawei’s new satellite phone can use satellite phones without using an external antenna. It seems really powerful? But because I have never used an ordinary satellite phone, I am not sure. If an ordinary satellite phone does not need to be transferred to a mobile phone to find stars, then Huawei’s satellite phone may not be a big deal. It’s not difficult. However, if ordinary satellite phones also need to aim at satellites to communicate, then Huawei should still be a bit level.

I’ve seen a few dismantling videos of this mobile phone, but there is no obvious trace of the antenna anywhere. The satellite phone should need a relatively large antenna… so where can it hide the antenna? I wonder if that huge vapor chamber is an antenna? Originally made of copper, it may be normal to be an antenna, but I am in the cloud after all, so I am not completely sure ? .
As for adding the function of satellite phone to the smartphone… In fact, I think this is an inexplicable behavior. Redmi K60 Pro) is also cheaper than Huawei Mate 60 Pro, and the flexibility and performance of the mobile phone are better. I don’t know how much the addition of this satellite phone function will increase the cost of the mobile phone. If it is a lot, I think I have a mental illness Manufacturers will do this. After all, satellite phones are not used in most cases. In many cases, satellite signals cannot be received when there is no mobile signal, such as buried in ruins or in elevators. In addition, you can only use China Telecom’s SIM card, and you have to open a package, and you can only use Tiantong satellites. Do you have to buy other satellite phones for a trip to a farther sea? ? . Of course, if the cost is very low, for example, the vapor chamber can be used with an additional chip, then I think it’s okay, but the sales price is too expensive, but the company wants to make more money, which is understandable ? .

As for the layout of 6G that some people say, it is even more ridiculous. If 6G is really a satellite network, it is impossible not to add an antenna. I believe that no one will want to aim at the satellite to surf the Internet, and the satellite network cannot do it anyway. It’s faster than ground base stations, so it’s not that 6G is slower than 5G. ? .

feelings

Satellite communication seems to be advanced, but the essence is that it flies faster (synchronous satellites may not need to consider this…), it is farther away (Tens of thousands of kilometers is actually quite far away ? ) It’s nothing more than communicating with a radio station. If it’s simpler, you can communicate with people a few kilometers away with a laser pointer, so it’s really not a difficult task. Think about how humans can communicate with Voyager 1, which has traveled far. Don’t you think it’s actually okay?

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