Understanding the Electromagnetic Spectrum
To start we need to define and better understand radio-frequency (RF) radiation. It’s the second term that gets people’s attention and fear – radiation; it connotes images of Hiroshima, nuclear fall-out, and painful death – hence the longevity and far reaching effects of radiophobia as mentioned earlier. But, let’s put things into perspective. Fundamentally, at its core, radiation isn’t as frightening a word as it might seem. Radiation, as it is defined, is the release of energy from any source; as an example, the heat that comes from burning logs in the fireplace in the cold of winter can be considered radiation – and we all can agree that a good fire on a cold winter’s day is a good thing. RF radiation is just a fancy term for radio waves, which are a form of electromagnetic energy which consists of waves of electric and magnetic energy moving together (or radiating) through space. They’re a natural occurrence in the physical world.
Diving deeper, the graph above depicts the electromagnetic spectrum. It breaks the spectrum into two zones; non-ionizing radiation and ionizing radiation. The upper end of the electromagnetic spectrum is considered harmful to humans. This area contains ionizing radiation, which includes X-rays and gamma rays. Essentially this means that anything in this spectrum can break apart molecular bonds and damage DNA; when we talk about damaging radiation, we are referring to this segment of the spectrum (which is why when you get your leg X-rayed, they put a lead-lined bib around you to limit the area where your body is exposed). The remaining spectrum is what’s considered non-ionizing – these frequencies have wavelengths that are too long to be able to actually damage human cells; and this is where we find most of the frequencies we are using for communication and connectivity. Even the highest frequency in the 5G spectrum are far below the boundaries between ionizing and non-ionizing waves.
The term 5G encapsulates a wide variety of RF spectrum, it’s not just a one-size fits all application. It’s primarily three specific spectrums and classified as low-, mid-, and high-bands. To put it in real world use cases, rural environments may fall into the low-and mid-band spectrum due to the nature and geography of their locales and the need for distance to travel from device to tower and the low density of individuals using the network. While urban environments, because of their dense populations and small geographical footprint, will need to utilize the high-band frequencies due to its spectral-reuse capabilities and shorter distances needed to travel. In both cases the goal is to deliver fast, reliable, low-latency, and deep throughput connectivity.
The wireless industry is primarily focused on using mid- and low-band frequencies for 5G, because deploying a massive number of towers and access points needed for high-band usage will be time-consuming and expensive. But high-band technology is the “cutting-edge future” of communications and connectivity and will eventually be brought into daily use. That being said, 5G will continue using the same radio frequencies in the low- and mid-band that have been used for decades for radio and TV broadcasting, satellite communications, Wi-Fi, and mobile communications. 5G is blending the old dependable frequencies (Medium Frequency – AM/FM Radio & TV) through and to the newer high-band frequencies (Extremely High Frequency – MM-wave) to create the next generation “super-highway” of fast, deep, and reliable communications.
5G & Small Cell
Most concerns about safety and health stem from the use of millimeter-wave technology. These are high-frequency radio waves that are supposed to deliver much faster speeds (up to 10 Gbps), that make up the high-band spectrum (SHF and EHF). Millimeter-wave transmissions, however, are far less reliable at long distances than transmissions using the lower frequencies (low-band and mid-band) that mobile carriers have traditionally used. To provide reliable, ubiquitous 5G service over millimeter-wave frequencies, carriers will need a larger number of smaller locations, called micro-cells or small cells, that are needed in order to utilize the higher frequencies of the spectrum properly; specifically in the dense urban environment of our cities. The densification of our towers is a major concern leading to the “noise” around 5G and health; some estimates that the US needs another 300,000+ towers to meet the needs of 5G.
The fear related to 5G stems specifically from this issue, claiming that the more towers needed equals more radiation exposure. There are significant issues with this claim, however. Higher frequencies don’t behave like the traditional frequencies in use today. The differentiation lies in the attenuation and propagation of mm-wave signals.
The first differentiator has to deal with the attenuation of mm-wave frequencies within the atmosphere, which impacts the distance the transmission can travel. The original use of these frequencies was in low-Earth orbit to communicate with satellites. In a vacuum, mm-waves are great related to their ability to send and receive large volumes of information (throughput) directionally. The problem with mm-waves as you bring them closer to earth is the atmosphere. Earth’s atmosphere has a nasty habit of absorbing mm-wave frequencies; in fact you could say that it actually “eats” them. The graph below shows the attenuation rate of mm-waves as they interact with the atmosphere. Water vapor and oxygen are the two factors in our air that reduce the distance that these mm-waves can travel. What happens, in effect, is that these frequencies cannot travel the distance that low-band and mid-band frequencies can; they’re mitigated by characteristics in our atmosphere.
The second differentiator revolves around the directional characteristics of mm-wave frequencies. Low-band and mid-band frequencies are omni-directional and radiate outward in all directions much like a ripple in a pond after a stone has been dropped into it. Macro-towers, the large three-sided cell towers with the large antenna that you see today, are designed to get the low-band and mid-band signals out to your cell-phone – circulating in all directions.
MM-waves do not behave this way. They are uni-directional and go in one specific direction, much like a flashlight beam travels. It is directed in its travel and doesn’t radiate outward like the much lower frequencies.
These two issues are why the need for more towers are necessary. The difference being that the new towers won’t be large macro-towers, and the antenna won’t be the large ones mounted on them. Because of the directional nature of the frequency, the signals will be steered (known as beam forming) from tower to tower. The antennas, for the most part, are the size of a backpack and will be placed on existing infrastructure like light poles and phone poles and these will become the new 5G towers. Because of the attenuation of the signal, in order for the signal to propagate, you need more towers, like the space between phone poles and light poles, so that you can get the distance out of the frequency. Again, these are directional and therefore aren’t radiating signal in all directions – just targeted ones. This approach is called “small-cell” and will be the backbone of communication protocols that will allow for self-driving cars to happen, for example.
Due to the nature of mm-wave frequencies more towers will be needed. However, the concern that the more towers there are, the more our bodies are exposed to RF radiation is not a real issue. The RF radiation in this case, unlike radio, TV, and 1G – 4G, isn’t omnidirectional and therefore won’t be everywhere. We will need densification of towers in order for mm-wave frequencies to work because of the shorter distances the waves can travel, but these 5G small cells will steer the signals from tower to tower and tower to device in tighter “beams”, rather than flooding the environment.
Dr. Bill Curry & “the Graph”: The “Established Science” Behind the Fear
Which leads us back to the central premise – what is driving all of the fear related to mobile communication? In order to put things in perspective, we need to look through the lens of the past. We need to focus on a school system looking to purchase laptops for the 250,000 students that make up the school district.
In early 2000, the Florida school district of Broward County was interested in purchasing laptops for their 250,000 students. They were concerned about the effects of Wi-Fi, which they wanted to use throughout the school, on the students; the driving question being,”would Wi-Fi negatively impact the health of the students”? They hired a physicist to conduct the study – his name was Dr. Bill Curry.
In his research, Dr. Curry looked at studies on how radio waves affect human brain tissue, and came to a startling conclusion – based on his findings, radio waves could cause brain cancer. This was a chilling discovery. Curry put a chart together which summarized his findings. The chart showed the dose of radiation received by the brain, rising from left to right, with the increasing frequency of the wireless signal. What he found was that the higher the frequency, the more impact it has on brain tissue (below).
This single chart has been the key driver for fear and anxiety related to mobile communication and connectivity technologies ever since its publication. As it pertains to specifically to 5G, the anxiety has become more pervasive because we’re beginning to use the frequencies where the curve significantly accelerates.
Dr. Curry conducted his research in a lab where he could control his experimentation. He used exposed brain tissue and subjected it to the radio frequency spectrum in his studies. And here is the core issue that questions his results; in real world applications the brain isn’t openly exposed – it is surrounded by bone and other tissue.
The other problem with Dr. Curry’s findings, is that he didn’t take into consideration the propagation effects of mm-wave frequencies in his research and how these mm-waves interact with the skull and tissue surrounding the skull before it can get to the brain. As frequencies get higher, the wavelengths get smaller. In non-ionizing radiation at these high frequencies, the wavelengths don’t penetrate objects (wood, stone, metal, glass), but rather they bounce off, like a rubber ball on concrete. Penetration doesn’t happen.
60 Ghz, for example, which has a 5 mm wavelength is a great solution for wireless communications inside buildings for its privacy characteristics due to attenuation (as explained above). This frequency cannot penetrate walls or glass; this allows for secure wireless communications to take place because unless you’re in the room where the signal is, you cannot access it because it doesn’t permeate or penetrate the solid objects that are surrounding the room, the aforementioned walls and glass. It bounces off of them. It’s a wireless solution that lawyers (who don’t use Wi-Fi due to security concerns, ie: hacking) could utilize as its security attributes create a “SCIF-like” private and secure environment.
Curry’s core premise, therefore, becomes moot when applying the propagation effects of mm-wave frequencies to the human body. Brain tissue can’t absorb the energy, as Curry professes, because the energy can’t penetrate through the tissue nor the bone surrounding the brain. Humans, as it turns out, are literally pretty dense. Our skin is made up mostly of water; add to that the solidness of the human skull, and MM-wave frequencies aren’t getting anywhere near our brains to allow any energy absorption to occur, they bounce off us.
It is interesting to note that David Carpenter, Director of SUNY’s Institute of Health and the Environment, who is a notable critic and alarmist of wireless technology (and an early supporter and spreader of Curry’s findings), recently conceded in a New York Times interview that it could be possible that increasingly high frequencies could have difficulty entering the human body. “There’s some legitimacy to that point of view,” he is quoted saying, adding that if human tissue, like skin, blocks 5G signals, “maybe it’s not that big a deal”.
MAYBE IT’S NOT THAT BIG A DEAL. Wow. “Maybe it’s not that big a deal” is the best response David Carpenter can bring after after his loathing of technology and impeding the growth of wireless connectivity for decades? It would be sad if it wasn’t so stunning and nonchalant in its delivery.
On a side note, here in Michigan, Carpenter takes on significantly more importance in spreading this misinformation because his was the main testimony used in 2012 to a Michigan state board assessing wireless safety, using Curry’s graph and findings at the core of his testimony. It was after this interaction that Curry’s graph began to make the circuit to other critics and alarmists and began to gain more traction.
This one flawed scientific study by Bill Curry has been the catalyst for creating fear surrounding mobile communications and connectivity going back 20 years. It has been cited as the core “witness” in numerous lawsuits and studies relating to the safety of wireless connectivity and unfortunately has been established as fact among activists, like David Carpenter. The only problem getting in the way of “established fact” is the imprecise nature of the study itself. MM-wave frequencies’ propagation behavior and the natural protection afforded us by our bodies, insures that Curry’s biggest fear is not a fear at all.
