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Category Communication

HOW DO COMMUNICATION SATELLITES WORK?

The layer of the Earth’s atmosphere called the ionosphere can reflect some radio waves back to Earth. This is used for sending messages over fairly short distances, but for messages to travel further across the Earth, the radio signals can be bounced off a satellite, orbiting almost 36,000km (22,000 miles) above the Earth’s surface. Several satellites, in different orbits, are required to give coverage over the whole globe, and different satellites are used to reflect signals for different media, such as telephone messages and television pictures.

A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals through a transponder. It basically creates a communication channel between a source transmitter and a receiver at different locations on earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are currently 2,134 communications satellites in the earth’s orbit and these comprise both private and government organizations. Several are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky. The orbital period of these satellites is the same as the rotation rate of the Earth, which in turn allows the satellite dish antennas of ground stations to be aimed permanently at that spot; they do not have to move along and track it. Since the high frequency radio waves used for telecommunications links travel by line of sight, they get obstructed by the curve of the earth. What these communications satellites do is they relay the signal around the curve of the earth thus making possible communication between widely removed geographical points. Communications satellites use a wide range of radio and microwave frequencies. To avoid signal interference, international organizations have regulations stating which frequency ranges (or bands) certain organizations are permitted to use. This allocation of bands reduces the chances of signal interference.

A group of satellites working together is called a satellite constellation. Two such constellations are supposed to offer satellite phone services (mainly to remote areas), are the Iridium and Global star systems. The Iridium system has 66 satellites. It is also possible today to provide discontinuous coverage using a low-earth-orbit satellite that can store data received while passing over one part of earth and transmitting it later while passing over another part. The CASCADE system being used by Canada’s CASSIOPE communications satellite is an apt example.

A satellite in orbit has to operate continuously over its entire life span. It needs internal power to be able to operate its electronic systems and communications payload. The main source of power is sunlight, which is harnessed by the satellite’s solar panels. A satellite also has batteries on board to provide power when the Sun is blocked by Earth. The batteries are recharged by the excess current generated by the solar panels when there is sunlight.

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HOW HAVE MODERN COMMUNICATIONS CHANGED OUR LIVES?

Modern communications have affected our lives in numerous ways. Being able to pass information down telephone wires or via satellites means that some people can work from anywhere in the world and still keep in constant touch with their offices. A surgeon in Arizona, via a satellite link, can assist a colleague in Beijing with a complicated operation. News can travel halfway around the world as quickly as it can reach the next town. Perhaps the biggest effect of communications has been to make us all feel that the world is a smaller place, and that we need to be concerned about its future and the futures of people thousands of miles away.

The Internet has turned our existence upside down. It has revolutionized communications, to the extent that it is now our preferred medium of everyday communication. In almost everything we do, we use the Internet. Ordering a pizza, buying a television, sharing a moment with friend, sending a picture over instant messaging. Before the Internet, if you wanted to keep up with the news, you had to walk down to the newsstand when it opened in the morning and buy a local edition reporting what had happened the previous day. But today a click or two is enough to read your local paper and any news source from anywhere in the world, updated up to the minute.

Technology has improved communication, especially in recent years. We’ll always have so much information readily available at our fingertips. Writing letters to relatives living hundreds of miles away is so old-school! Instead, you can talk to them through a video call or instant messaging. This change in communication has completely changed relationships all over the world.

Services like Facebook and Twitter have also become a big part of our everyday lives. These sites allow people to see a lot of information and photos at once and are enjoyable by design. When you upload a photo to the Internet, it doesn’t simply go away. It stays for a long time. This means you can use technology to store memories that are important to you, like family photos.

With modern technology, we can live much healthier lives. Those who have fitness trackers can see how active they are. Seeing that can encourage us to be even more active. Some fitness trackers like the Apple Watch even gamify health with competitions and points!

New technology can help create cures and medicines. Someone who is sick in modern times is much more likely to be cured than someone in past times. Modern technology can automate just about anything, from turning on a light to ordering a pizza. With automation, we can do so much more in such a small amount of time. For example, you can use your voice to start the coffee maker while you’re still getting dressed.

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HOW MUCH HAS THE SPEED OF COMMUNICATION INCREASED?

Only a few hundred years ago, the fastest way that a piece of news could travel was to be carried by a person on horseback. Messages sent overseas could only travel as fast as the fastest sailing ship and were at the mercy of the wind and weather. The development of steam locomotives and steamships made it possible for information to move around the world more quickly, but it still had to travel physically from one place to another, as a letter. The breakthrough came with the invention of the electric telegraph and messages in Morse code. The message was sent down a wire in bursts of electric current. Today, images of written documents, sound recordings or television pictures can be flashed around the globe in less than a second by means of satellites and radio communications.

It seems like advancements in technology and changes in communication always go hand in hand. When science was working to introduce new tools to let distant people contact each other, the landlines replaced telegraph and subsequently, cell phones replaced landlines. When the Internet arrived, it not only brought revolution in the sales industry but also opened new doors of personal communication. When science was looking for more convenient ways to send messages, e-mails replaced postal emails and social media replaced text messages. So it would not be wrong to say that technology has been shaping the communication industry for over a hundred years.

Previously, there were not much mediums of communication and today we are completely overwhelmed with the disparate mediums, thanks to the ever-changing technology! From Facebook to Instagram and skype to Whatsapp, we now have the limitless database of communication tools that have brought us closer to the entire world. All these communication mediums have also impacted our lives in different ways. For example, it’s true that Smartphones have brought us closer to our friends and relatives living in distant places, but at the same time, they have also made our society somewhat impersonal. Although they have helped increasing workplace engagement and productivity, they have also given rise to certain security and privacy issues.  While some of these issues are relatively minor, but some may have profound effects on the lives of users.

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WHAT WERE THE EARLIEST FORMS OF COMMUNICATION?

Early people probably communicated through a combination of primitive sounds and basic sign language. Languages may have evolved through a need for survival — warning others of danger, for instance. They developed gradually as people used the spoken word for instruction and entertainment. Oral communication, particularly through story-telling, was and still is an important part of a society’s culture.

Making sounds such as grunting or guttural sounds at a low pitch or high pitch would indicate either social communication or be a warning sign. Body language was also used as communication at this time.  Later written communication came about when humans realised the need to record their daily life activities. Further down the line this progressed to meeting the needs of bartering and exchanging of goods. The ancient Egyptians were amongst the first people to use symbols as a form of written communication which later developed into the alphabet system that we know today. 

Cave drawings were murals that people painted onto the walls of caves and canyons to tell the story of their culture.  They would tell stories of battles, hunts and culture. Storytelling was used to tell stories, both fiction and nonfiction, before there were books.  It was a way for families and communities to pass on information about their past.

Drums were one way to send signals to neighbouring tribes and groups.  The sound of the drumming patterns would tell them of concerns and events they needed to know. Smoke signals were another way to send messages to people who were not close enough to use words with.  Can you imagine living without your telephone?  We sure have come a long way!

For many years it was widely believed that the only reliable form of knowledge was the written word. Books, diaries, documents, and newspapers.These commanded respect because their words could be preserved. But the printed word can be misleading. For example, certain history books taught, inaccurately, that Africans arrived in Southern Africa at more or less the same time as European settlers landed in the Cape. Some books emphasised differences amongst people. And while most textbooks acknowledged that the Khoisan had lived in South Africa for a very long time, the writers saw them as ‘primitive’, and paid very little respect to their history.

When European settlers arrived in South Africa, most of them could read and write. They valued the written word as a precious form of knowledge. But European scholars made the mistake of thinking that writing was the only way that knowledge could be passed on. Where they did not find books in Africa, they simply assumed that Africa had no history.

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The art of listening

I have heard that listening is very important in communication. How can I improve my listening skills?

Listening is the first step in good communication. Speaking is the second step. According to me there are three kinds of listening. I would like to call these as three dimensions of listening.

First, there is factual dimension. At this level language is merely a statement of fact. For example, when someone informs us that it rained last weekend or that a company has increased its profits by 10 percent, we listen to statements of facts. Listening to such facts does not require much subtlety; anyone with a certain amount of attention can do that.

The second dimension of language is the intention. At this level one has to listen to more subtle intent behind what a speaker says. When a boss tells a subordinate, “I appreciate your coming to the office on time today,” she is conveying a different message from what the mere words would communicate. The subordinate who listens well reads the message as, “I do not appreciate your coming late to the office every other day”. Intentional listening requires greater attention and energy on the part of the listener.

The third and the most subtle dimension of language is the transformational dimension. Language has a certain alchemy that can transform the heart and mind of the listener. This transformation comes about in the listener through a process known as empathy. When listening is very deep, the listener is in touch with the spirit behind the speaker’s words. He listens with his heart behind his ears. The focus of the listener is not merely on the words or the intention behind them but on the raw energy of the words.  

This last kind of listening is the most effective. Try it!

 

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My voice is very low and shaky. I find it very difficult to talk in public. Please let me know how I should train my voice.

Your voice is a very important tool of communication. The tone, the volume and the pinch off your voice communicate a lot more than your words. A baby attracts much more attention by crying aloud ‘Wah’. The baby’s power of ‘wahs!’ is greater than an adult’s power of words.

Your voice conveys a lot when it is deep and deliberate. By the force of our habits and social conditioning we begin to believe that we can speak in only one type of voice. As a matter of fact you can vary your tone and voice-type with a little practice. In the privacy of your study you can deliberately change your voice by imagining you are a different person. Movie actors often practice speaking in different voices. Here is a voice-enhancing exercise prescribed by my teacher Justin Cohen that will help you develop your voice:

  1. Sit in a relaxed upright position or lie down
  2. Breathe deeply and slowly. While breathing in, your abdomen should expand. As you breathe out, it should contract. Your chest and shoulders should remain still.
  3. Now, each time you inhale, allow the air to slightly vibrate your vocal chords so that they let out a soft deep sound like-Ahh!
  4. While remaining relaxed, push the air out a little harder allowing the sound to grow louder and longer.
  5. Now close your mouth and feel the air vibrate against your lips in a humming sound. If you are relaxed enough, your lips will tingle.
  6. Finally, open your mouth and let the voice out with a little more volume. You can notice your body vibrating faintly like a washing machine.

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What is a modem?

 

               Computers that are connected to a telephone line incorporate a device called a modem. It turns signals into a form that can be transmitted along the telephone line. The name ‘modem’ comes from the term Modulator-Demodulator. The device modulates, or changes, the digital signal from a computer into an analogue signal, which is the type of signal that travels along telephone lines. The modem decodes or demodulates the signals it receives back so they can be read by the computer.

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How do mobile phones work?

 

               Mobile phones, which are properly called cellular phones, allow calls to be made wherever the caller happens to be. They are called cellular phones because a territory is divided up into a series of small areas, or cells, each with a small radio station. When a call is made, the telephone sends a radio message to the base station, which in turn passes it to a mobile phone exchange. Here the signal can be routed to the ordinary telephone system, or transmitted back to another mobile phone. Mobile phones use low-powered microwaves to send and receive messages to and from the base station.

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How do we receive messages and TV pictures from a satellite orbiting the Earth?

               Television pictures, radio and telephone communications are bounced off satellites to cover the greatest possible area of the world. Satellites orbiting the Earth must travel at high speed to escape being brought down by the Earth’s gravity. As the Earth itself is spinning rapidly, there is a point above the Earth’s surface where the orbiting speed of the satellite can be matched with the rotational speed of the Earth. At this point —35,900 kilometres above the Earth — the satellite appears to stand still and is said to be in a geostationary orbit.

Geostationary satellites can be positioned right over the areas where they are needed. They can also be used as spy satellites, because they remain constantly over a region of interest.

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How can television pictures be transmitted by radio waves?

               Television cameras break a picture into electrical signals, separating them into three colours (red, blue and green) and turning them into coded messages. Sound is recorded and coded at the same time. The coded pictures and sounds are transmitted by radio waves, electrical cables or optical fibres to the receiver. Inside a television receiver the signals travel to three electron guns — one for each colour. The electron guns emit streams of electrons, which are directed at a fluorescent screen. Magnets bend the electron streams so that they scan back and forth from top to bottom, exciting the phosphors in the screen and producing a colour image. They scan so quickly that our eyes see the images as a continuous picture.

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