2023 will be the 50th anniversary of the invention of the mobile cellphone by Martin Cooper.
The number of mobile phones that are in use today is greater than the population of the Earth. Given the widespread use of this technology, very few people know how they work. Fewer still know how to use them safely.
When you speak into your mobile phone, you are actually speaking into a microphone located near the base of the phone. This speech is converted from voltage amplitudes to digital data – 0’s and 1’s. The mobile phone then transmits this digital data to local cell towers. When someone talks to you, the cell tower sends packets of digital data (0’s and 1’s) to your phone. These are then converted into voltages and are fed to a speaker in your phone. The transmissions themselves are radio waves. Typically, the phone will assign “0” to a lower frequency and “1” as a higher frequency. It is a combination of the strength (amplitude) of radio waves and the frequency that can be harmful to a person. Signal strength is easy to understand. When you turn up the volume of your car radio, you are increasing the amplitude (strength) of voltages to your speaker. This will allow you to hear music at a farther distance from the speaker. The same goes for radio waves. The greater the amplitude (strength) of the radio wave, the farther it will go and the more harmful it becomes. So, what is frequency?
When you turn the dial of your car radio, you are selecting the frequency of the radio station you wish to hear. For example, 104.5 FM means the station is transmitting at a center frequency of 104.5 MHz (megahertz). The units for frequency, MHz in this example, tells you how many waves are seen in 1 second. So, 104.5 MHz implies 104,500,000 waves per second are transmitted. The music from the radio station is carried to your radio at that frequency. 4G and LTE phones transmit in the USA at about 700 to 800 MHz. Typically, the phone will assign “0” to a lower frequency and “1” as a higher frequency.
A spectrum analyzer (shown in the picture to the right) is a piece of laboratory equipment that will measure the frequency and signal amplitude of transmitters. The picture shows two peaks detected from a mobile phone transmission to a cell tower. The peak to the left is the “0” digital data and the peak in the right is the “1” digital data as described earlier. While you are talking, you will see the peaks appear. When you are silent, they go away.
“1” data from person talking on mobile phone
“0” data from person talking on mobile phone
When someone is talking to you on a cellphone, you are receiving radio waves from the cell tower. They must travel a long distance to get to you – often passing through vegetation, walls, and windows. By the time the signal reaches you, it is extremely weak. Its strength is so low that there is little to no hazard to your body. But when you speak into the phone, the transmitter needs to send high strength radio waves to make it through the walls, windows, vegetation, and back to the cell tower. Therefore, you are exposing yourself to high strength radio waves (EMF) when you speak and very little when you listen. The safe way to use your phone is with the speakerphone to minimize the energy going into your skull or body when you talk.
When you are driving in a remote area, your car radio may start to pick up what is often called “static,” or “interference.” You hear this interference as an annoying crackle, hiss, or buzz sound mixed with the radio station music. It is often caused by radio waves bouncing off trees or mountains and colliding with those radio waves that had a direct shot from the radio station. This colliding weakens the signal received by your car radio. This is similar to the way WaveBlock works.
The application of WaveBlock shield to the back of the phone causes radio waves to deflect from its surface. Those waves collide with waves bouncing off other items in the phone, like the screen. The result is weaker escaping radio waves from the phone. Because phones are digital, the data (0’s and 1’s) are often repeated several times so the cell tower still ends up receiving the entire voice data. Sometimes you see the marketing term “error correction,” used to describe this repetition. All phones have error correction. The calls go through just fine without the crackle, buzz or hiss, but the radio waves that are emitted toward your body are much less with WaveBlock.
What about BlueTooth or WIFI calling (also known as Voice over IP – VoIP)? Is that safer the cellular calling? The answer is yes. The higher the frequency, the less radio waves are absorbed into the body. The skin basically begins to reflect more of the energy away from the body. If your phone supports 5 GHz WIFI, you get about 2 times more energy reflected from the body than at the 4G/LTE cellular frequencies from cell towers. And WaveBlock also helps to reduce transmitted signal strength at these frequencies even further when applied to the phone. Deflection and internal interference lowers the power levels of phone’s onboard Bluetooth and WIFI.
What is the safest way to use your phone?
1. If you are in your car, use Bluetooth connections to your car’s radio to make and receive calls. Keep your phone as far away as possible from you. Use WaveBlock on the back of the phone to make all calls safer.
2. When at home or work, use WIFI calling and your speakerphone. WaveBlock applied to the back of the phone will make any type of call safer.
3. If you can’t use your speakerphone, use wired earbuds or a single wireless earbud with WaveBlock applied.
Author: Eddie Hughes, Tek Voyeger