We deal with the myths (whether?) About the dangers of communication and where does the coverage area
Disclaimer
This article is for general informational purposes and is not a sanitary verdict on the safety of radiation. In each specific case/location, independent measurements and assessments must be made.
It is obvious that powerful sources of radio emission and phased antennas (including StarLink terminals) exceed safe limits in the direction of their work, but these areas are always marked with warning signs and / or instructions.
All health, and drove to understand!
introductory
Following the results of the last article, I received a lot of feedback in a personal message and realized that it was urgent to clarify about radiation doses and their associated wireless coverage areas.
I’ll start from the end – you definitely won’t get any significant radiation dose from satellites, because. in fact, the problem is diametrically opposite: the energy drops cubically with distance, and it’s hard to accept anything at all 🙂
But modern telecom, and especially thoughtlessly stuck Wi-Fi in rooms with thick walls – in some cases can really cause increased exposure.
What’s with the walls?
The thicker/dense the walls, the better they absorb high frequency signals. Alas, instead of optimizing the location of sources and consumers, the power or density of the Wireless equipment is often twisted.
And the more radio sources, the less efficient they are due to interference, which leads to recursion.
What is SAR?
“Specific absorption coefficient (English specific absorption rate, SAR) of electromagnetic energy – an indicator that determines the energy of the electromagnetic field absorbed in the tissues of the human body in one second.
So SAR is literally J/s/kg = which is “power per unit mass” W/kg.
Skinny/fat adult/child, is there a bonus?
In general, body weight is not important at all, because SAR should be understood more as radiation density, usually applicable to local volumes – for example, when we put the phone to the ear, the nearby tissues may indeed experience an excess of the allowable SAR value. factor of.
On the other hand, there datathat children are exposed to twice as much radio loads as adults, but I was not able to get acquainted with the measurement technique in detail.
With kilograms, everything is more or less clear, but what is the power (Watt) of radiation? If you do not go into the fundamental jungle and simplify to the everyday level, then this product of carrier frequency and amplitude (value) of the signal.
Just like on a sea beach: while low and rare waves caress your legs – everything seems to be ok, but the higher and more often these very waves become, it somehow becomes not ok 🙂 Actually, to generate more frequent and / or high water waves – the wind needs to spend more energy per unit of time, which is the transmitted power.
Continuing the analogy: the tissues of the body have a certain mechanical strength, and, obviously, there are sea waves of such power that they already lead to damage and injury.
For reference: in different countries have different SAR standards (and by the way, sanitary standards EMI RF in the CIS are among the most stringent in the world), with values of the order of 1.2-2 W/kg.
Back to telecom
Wave radiation works in exactly the same way: the lower the frequency and magnitude of the signal (wave) – the safer for everyone whom these signals reach.
I think the sophisticated reader has already understood what the fundamental contradiction is, but I am obliged to voice this rhetorical question: so why does the communications industry want to exclusively increase AND frequency AND amplitude?
The signal strength is literally proportional to the distance from which it can be registered: the stronger the source signal, the farther from this source you can get a connection.
In turn, the operating frequency is literally a bit rate: the more often the signals follow, the more data can be transmitted per unit of time.
It turns out that “ideal” coupling is an infinitely high frequency with an infinitely high amplitude signal.
This is where the regulated radiation limit (SAR) comes into play so that we do not literally get fried from this “ideal” telecom, in which there is no place for anything living. All modern communication equipment must comply with sanitary regulations that prevent any significant damage to human health.
However, I recommend using headsets…
Eat really disturbing research, where it is shown that at the moment of establishing a connection (1900 MHz) by a mobile phone at the ear, the limiting radiation dose is locally exceeded by almost 5 times. This is the very moment when the surrounding speakers hear this known to all pip-pip.
At the same time, already at a distance of several centimeters, the signal is significantly weakened.
Use headsets! And this is not advertising at all.
gigabit or coverage
Finally, we translate all the pain of signalmen into everyday concepts: either the speed or range connections.
At the same time, the main request for communication is formed by residents of cities, who require an increase in speed, first of all, even at the cost of the coverage area. In this connection, manufacturers of telecom equipment have to consciously reduce the signal strength in order to keep the final power limit unchanged.
With each generation of communication, the frequency grows more and more, and the radius becomes smaller.
It should be noted that due to the development of modulation mechanisms and algorithms, as well as huge progress in signal filtering, the decrease in radius is always less than the increase in speed.
Apogee of the problem
Jokes aside, but the current Cell-5G and Wi-Fi6 standards in a real urban environment already have a radius [всего] hundreds, and sometimes tens of meters.
Of course, countless tricks were invented – encodings, amplitude and phase modulations, as well as signal phasing in a specific direction. This is clearly seen in the example of Wi-Fi generations, where the overall balance of bitrate and range is also maintained.
It should be especially noted that the upcoming Next-gen Cell / Wi-Fi (6.7G) at frequencies of 30-100 GHz (!) And even more so is declared as “microcells”, i.e. communication towers or a router should be literally next to you.
It is extremely ironic that with the need to sit literally close to the router, as well as the growth of mutual noise from wireless sources – the “good old” cable suddenly again becomes almost the “top of development” of the current telecom.
Afterword
It was the forced, but well-founded movement of the world telecom towards the reduction of the coverage area that became a powerful impetus for the development of low-orbit communication groups StarLink, OneWeb, Kuiper, GuoWang, BlueWalker (see IT-HW: what is the StarLink-V2 Revolution? (Part 1) ).
Obviously, satellites cannot provide channel speeds comparable to terrestrial infrastructure, but they effectively close the lion’s share of the inhabited planet with guaranteed communications.
