Many of us are already accustomed to a wireless network, as if it has always enveloped the world and allowed access to the Internet with only a small communication device (tablet, netbook, smartphone). However, Wi-Fi appeared not so long ago, and although it greatly simplifies the life of a modern person, there are some facts that many do not know about …
Wi-Fi first appeared in Hawaii. ALOHAnet was a pioneering computer networking system developed at the University of Hawaii. She provided the first public demonstration of wireless packet data transmission. This happened in 1971. And only 20 years later, NCR and AT&T corporations invented WaveLAN technology, which is considered the real predecessor of Wi-Fi. Then, in 1997, the first version of the IEEE 802.11 wireless protocol was released.
And back in 1991, At & t launched the first devices for wireless data transmission at 2.4GHz radio frequency on the market. Then this standard was called WaveLan. He could provide data transfer at speeds from 1 to 2 megabits per second.
In 1997, the world saw the first 802.11 specifications. It was essentially the same WaveLan from At & t. And the proud name of WI-FI has already received the next specification - 802.11b. This standard allowed data transmission at a speed of up to 11 megabits per second.
In 1999, brand consulting firm Interbrand took over the promotion of Wi-Fi technology. She designed the Wi-Fi logo, which is a variation on the Yin and Yang theme (hinting at the compatibility of all Wi-Fi certified products).
Contrary to popular belief, Wi-Fi is not derived from the phrase Wireless Fidelity. This misconception stems from the early advertising slogan "Wireless Quality Standard". In fact, the name Wi-Fi means nothing.
In addition, the Wi-Fi Alliance (a trade association formed in 1999 to protect a trademark) requires the correct spelling of a term with two capital letters and a hyphen - Wi-Fi. Other spellings (WiFi, Wifi, wifi) are not approved by the alliance.
Wi-Fi uses radio waves. As you remember from your high school physics course, radio waves are a form of electromagnetic radiation. It includes gamma rays, visible light, radio waves, etc.
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The wireless adapter of a computer or tablet converts data into a radio signal and transmits it using an antenna. The radio waves are then received by the wireless router. It turns them into packets and forwards them to the Internet over a wired connection. Information from the Web comes in reverse order. However, this is a general description of the process. Wi-Fi has several notable differences from other wireless technologies.
For example: Wi-Fi operates at 2.4 GHz or 5 GHz. Wi-Fi frequencies are much higher than mobile phone frequencies, so the technology allows large amounts of data to be transmitted. However, all forms of wireless communication represent some kind of trade-off between power consumption, range and bandwidth. So for the sake of high data transfer speeds, I had to sacrifice other parameters: for example, Wi-Fi consumes a lot of energy and has a limited range.
Wi-Fi can transfer data faster than wires! At the moment, the fastest is the 802.11ac standard. It is capable of transmitting at speeds up to 1.3 Gb / s, which is much faster than a regular telephone wire.
The speed of 1.3 Gbps for wireless networks is far from the limit. Already, an active development of a new generation standard is underway - 802.11AD. Its bandwidth should be at least 7 Gb / s. It is achieved by operating in the 60 GHz range. It is a pity that such a high-frequency band has poor penetration and range.
What is the maximum range of Wi-Fi? The farthest connection that could be established between two devices operating on the 802.11 standard is 382 km. This record was set by Ermanno Pietrosemoli.
To do this, he needed to slightly finish the serial Intel equipment and tune the 2 directional antennas on top of each other so that they were in the line of sight. Ermanno managed to squeeze out 3 Mbps, and he spent only $ 60 on equipment!
Wi-Fi can work even up to 420 km away. And it is true! Using Wi-Fi, the Swedish Space Agency was able to transmit data to a space probe located at an altitude of over 400 km. However, the equipment itself for signal transmission was different from the standard - 6-watt amplifiers were used. And of course, there were no physical obstacles in the signal path.
For a typical router, the ranges are much smaller and depend on a number of factors. Signal strength can be affected by antenna, reflection and refraction, and transmitter power. A range of 30 m is considered normal, but in some cases the signal disappears already in the next room. Why does this happen?
A physical obstacle may be to blame. Radio waves pass through most obstacles, but can be absorbed by materials that conduct electricity. Water also conducts electricity, so our bodies can interfere with Wi-Fi. But don't worry, radio waves do not cause damage at the cellular level.
Another possible cause is interference. Since Wi-Fi uses radio waves (and there are many sources of them, including space), they can overlap and weaken the signal. In fact, microwave ovens operate at 2.4 GHz, potentially interfering with the Wi-Fi signal (especially if it operates in the 2.4 GHz band).
Is Wi-Fi radiation harmful? Such questions often began to sound after people learned that microwave ovens operate at the same frequency as WI-FI - 2.4 GHz.
If you delve a little into the essence of the issue, it becomes clear that the WI-Fi signal is absolutely harmless. Its power averages 100 milliwatts, while a household microwave oven operates at 800 watts. Wi Fi is completely harmless, because its power is simply not enough to harm you.
It is not safe to use public Wi-Fi networks. Such networks are often used by hackers to gather information. About 1 terabyte of data is intercepted daily. And every year 370 million accounts are "leaked" to the public. All thanks to the carelessness of users in public networks.
With the help of special software, you can intercept traffic between you and the server, then carry out a man-in-the-middle attack, pretending to be one of the parties. In this way, the victim's bank accounts are easily emptied.
In addition, you can intercept passwords or cookies with your saved session and log into your "contact" or "instagram" without any problems. To be on the safe side, try to avoid public networks. And if you really really want to, then use a secure connection over SSL or use a trusted VPN.
The wireless network came from a woman! And not just a girl associated with science, but an actress who became famous for shooting in the nude style. Today you will not surprise anyone with such a thing, but in the 30s and 40s, such an act caused a real wave in society (of course, most condemned the young actress Hedy Lamarr).
Moreover, many considered her to be frivolous and narrow-minded, but it was this girl who came up with a system that controls torpedoes from a distance - it was this development that became the basis for modern Wi-Fi.