14 February 2018

    James Francis

    How do cellphone towers work?

    Every time we make a phone call, we take for granted that we’ll be connected. But there is a world of fascinating tech behind every call.

    The history of telecommunications has always been revolutionary. The telegraph, for example, ended the horse couriers who would race from town to down with letters of importance. When the first transatlantic telegraph wire was established, it completely changed how countries did business with each other and even went to war.

    Not long after this, the telephone arrived, enabling our voices to be carried vast distances. Forget writing your message - now you could tell it to someone on the other end of the line!

    Today that seems so commonplace, because our world has grown used to instant communication. But even in our modern era, telecommunications have not failed to impress and change our planet. Go back a mere 20 years and hardly anyone had a cellular phone. Go back ten years and the smartphone was just getting started. In less than a lifetime, mobile communications have yet again shifted reality and improved our lives.

    But how does mobile communication work? The secret lies in radio signals…

    Radio, the miracle force

    Think of a radio tuned into a station or a television broadcasting the latest sports match. How does that work? The secret is the radio waves. A radio wave, as the name suggests, is a wave, just like those you see on the sea. They move in one direction, with a top part and a bottom part.

    Here’s an experiment to show how it would work. Take a saucer of water. On the one side, gently tap the water once to create a ripple - which is essentially a small wave. Note how the ripple hits the far edge of the saucer. Imagine someone is sitting on that side and that you have arranged a special code with them. One ripple is ‘yes,’ two ripples are ‘no.’ So if you touch the water twice, creating two ripples, the person on the other side can count two ripples and know your answer is ‘no.’

    Radio waves do something similar, only they do it much faster: at the speed of light, to be accurate. Thousands upon thousands of waves can be sent in a millisecond. But how can you tell one wave from the next? Unlike our example, where we count the ripples, radio waves can vary in height, called the amplitude. By altering the amplitude, mobile carriers are able to send voice, text and data information on the same infrastructure.

    You may also hear of radio frequency: this is how often the waves arrive behind each other and is normally constant.  

    The power of mobile towers   

    Everything using radio does this, even your home’s Wifi. But what the waves can do depends on the sophistication of the systems on either side. Mobile towers, which manage radio waves to and from your phone or dongle, are incredibly complicated. They manage voice, text and data over a wide range of frequencies. 

    When your phone communicates with a tower, it’s a very advanced moment. The tower not only discerns what kind of information is sent along the waves, but is also able to hand your requests to another tower as you move around.

    This is why mobile networks are expensive to build and maintain, because they are very sophisticated. It also explains why you see towers everywhere, as that ensures the best signal. More towers mean better signal performance, because there are more of the radio waves to go around. This is why Vodacom invented the cellphone tower tree, so we can enjoy the best in communication while not spoiling our beautiful skylines!

    So when you make that call, send that SMS or browse that website, spare a thought for the amazing technology in the background. The same natural forces that deliver a TV signal can be used to connect your entire life!

    -Photo by Steve Halama on Unsplash


    James Francis