Losses in mismatched line

In the literature described approximate formulas for calculating additional heat losses in uncoordinated transmission lines (cables, waveguides) due to standing waves. The limitation of such formulas is that the own losses of the matched cable should be up to 2 dB. Today, high-loss cables are increasingly used for microwave frequencies above 1 GHz. Broadband antennas often have a CWS 1. To find a compromise between the length of the line (for example, the antenna's suspension height), its cost, to estimate losses in a deliberately mismatched line (for example, 75 Ohm cable in 50 Ohm systems)...
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The Ministry of Communications proposed to switch to SIM cards with encryption from the FSB

The Ministry of Communications proposed to switch to SIM cards with encryption from the FSB
 
 
In order to implement the provisions of the "Yarovoi Law", the Ministry of Communications proposed to introduce on the communication networks Russian cryptographic protection systems, which will require the transition to new SIM cards. The draft order was published on the official portal of draft normative legal acts.
 
 
You can see it
by reference
.
 
 
Based on the data from the project map, the following is provided as a justification:
 
"The need to prepare a draft regulatory legal act is conditioned by the requirements for ensuring the integrity, stability and security of the unified telecommunications ...
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5G can replace cables - but not everywhere

Analysts from Citi have suggested (3r3r3? PDF
) That the 5G technology in the future can drive the cable Internet providers out of the market. Let's talk about how real this "threat" is: where the networks of the new generation will be able to replace the cables, and where - before this is still far away.
 
 
5G can replace cables - but not everywhere

 
/Flickr / kahunapulej / CC
 
 

Where 5G can replace cables


 
In the large cities

 
With a high probability of 5G ...[/h][/h]
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Seamless Wi-Fi-roaming: theory in practice

We deal with the technologies of roaming (Handover, Band steering, IEEE ???k, r, v) and conduct a couple of visual experiments demonstrating their work in practice.
 
 
Seamless Wi-Fi-roaming: theory in practice  
switch , to which both access points participating in the experiment are connected. Frames from one access point fell into one network card of the traffic collection system, the frames from the second to the second one. In the received dumps, only voice traffic was selected. The delay in switching can be considered as the time interval elapsed from the moment of traffic loss through one network interface, and before it appears on ...
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Decentralized messenger and a new generation telephone network

Decentralized messenger and a new generation telephone network  
 
Every time an article appears about a new messenger, most of the users of Habr in the comments are interested in - a centralized or decentralized IM?
 
If not, then - "everyone, guys, disagree".
 
Many, for example, also mention the decentralization of Skype, meaning what it was before 2011.
 
Let's then consider, as a liner and entry to the main idea of ​​the article, how Skype was in its golden years, before buying Microsoft.
 
 
(M1 Messenger) , which, on the one hand, is a decentralized messenger, and on the other hand can be defined as a next-generation telephone network.
 
 
In this platform...
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Networks for the most mothers. Part of the fifteenth. QoS

Networks for the most mothers. Part of the fifteenth. QoSSSSM-15. About QoS.
 
Now with the option Pull Request'ov .
 
 
And now we have reached the topic of QoS.
 
Do you know why just now and why this will be the closing article of the entire course of the SDSM? Because QoS is extraordinarily complex. The most difficult thing that was before in the cycle.
 
This is not some magical archiver, which deftly squeezes traffic on the fly and shuffles your gigabit into a hundred-gigabit uplink. QoS is about how to sacrifice something unnecessary, cramming the unintended into the framework of what is allowed.
 
QoS is so entangled in the aura of shamanism ...
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How SSH appeared on port 22

How SSH appeared on port 22 SSH by default it works on port 22. This is not a match. Here's the story of how he got this port.
 
 
When I ( Tatu Ilonen ) First published this story in April 201? it became viral: it was read by about ??? readers in three days.
 
 

The history of receiving port 22 for SSH


 
I wrote the first version of SSH (Secure Shell) in the spring of 1995. At that time, widely used Telnet and FTP .
 
 
But I still developed SSH for the replacement and telnet (port 23) and ftp (port 21). Port 22 was free and conveniently located between ...[/h]
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Cosmic Language, Part 2: Welcome, GJ273b

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Cosmic Language, Part 2: Welcome, GJ273b
 
The Ramfjorden installation of the European Scientific Association for Incoherent Scattering (EISCAT), located near Tromso in Norway. The installation includes several radio telescopes used to study the interaction of the Sun with the ionosphere and the magnetosphere of the Earth. To the left is a round parabolic swivel antenna with a diameter of 32 m, which was used to transmit a message to the side of Leiten star
 
 

Symposium "Language in the Cosmos"


 
In October 201? the researchers deployed a powerful radar telescope three times near the city of Tromsø in Norway, in the direction of ...[/h]
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The merger of telecom operators in 2018

The merger of telecom operators in 2018 The trend of recent years in Russia - the adoption of laws that affect the regulation of the telecom market. At the same time, telecom is a science-intensive and technological branch that acts as an engine for the development of the country's infrastructure. 2018 brought us several reasons to consider the merger of telecom operators closer.
 
 

Trends in legislation


 
Legislative regulation of the telecom is increasingly on the agenda of official and unofficial media. The reason for this is the "Yarovoi law", changes in the cost of ownership of frequencies, requirements for collecting and ...[/h]
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5G AGAINST WI-FI: WAITING AND REALITY

5G AGAINST WI-FI: WAITING AND REALITY  
 
Recently, the issue of the future of Wi-Fi networks in connection with the expected mass construction of fifth-generation cellular networks is increasingly being discussed. Indeed, why do we need Wi-Fi in a world where cellular networks provide billions of people with high-speed Internet access? Will the family of Wi-Fi standards stop with the arrival of 5G? Will technology leave the market, having completed its "historic mission"? Everyone who answered these questions in the affirmative is devoted to this article. We hope that all the others who understand network technology will also find it interesting ...
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