# data[].attributes.headline
Plan of the Laboratories works 3 semestr 2019-2020

# data[].attributes.subject
Plan of the Laboratories works 3 semestr 2019-2020

# data[].attributes.attachment_link.title
Plan of the Laboratories works 3 semestr 2019-2020

# data[].attributes.headline
Wireless Communication Technology Types and Advantages

# data[].attributes.subject
Wireless Communication Technology Types and Advantages

# data[].attributes.attachment_link.readable_text
The term wireless refers to the communication or transmission of information over a distance without requiring wires, cables or any other electrical conductors. Wireless communication is one of the important mediums of transmission of data or information to other devices. The Communication is set and the information is transmitted through the air, without requiring any cables, by using electromagnetic waves like radio frequencies, infrared, satellite, etc., in a wireless communication technology network.

At the end of the 19th century, the first wireless communication systems were introduced and the technology has significantly been developed over the intervening and subsequent years. Today, the term wireless refers to a variety of devices and technologies ranging from smart phones to laptops, tabs, computers, printers, Bluetooth, etc.

Types of Wireless Communication Technologies

In recent days, the wireless communication technology has become an integral part of several types of communication devices as it allows users to communicate even from remote areas. The devices used for wireless communication are cordless telephones, mobiles, GPS units, ZigBee technology, wireless computer parts, and satellite television, etc.
Satellite
Satellite communication is one of the wireless technologies, which is widely spread all over the world allowing users to stay connected virtually anywhere on the Earth. The Satellites used in this mode of communication, communicate directly with the orbiting satellites via radio signals. Portable satellite phones and modems have more powerful broadcasting abilities than the cellular devices as they have high range, apart from being more expensive in terms of cost, than their counterparts.

For example, for outfitting a ship through satellite communication, a traditional communication system is linked to a single satellite, which allows multiple users to share the same broadcast equipment.
Wireless Networking
Wireless Networking technologies connect multiple computers, systems and devices together without requiring wires or cables: a wireless local area network or WLAN comes under Wi-Fi.
WiMAX
There are wireless broadband systems that offer fast Web surfing without being getting connected through cable or DSL (Example of wireless broadband is WiMAX). Although WiMAX can potentially deliver data rates of more than 30 Megabits per second, yet the providers offer average 0 data rates of 6 Mbps and often deliver less, making the service significantly slower than the hard-wired broadband. The actual cost of the data available using WiMAX widely varies with the distance from the transmitter. WiMAX is also one of the versions of 4G wireless available in phones as Sprint's 4G technology.
Wi-Fi
Wi-Fi is a form of low-power wireless communication used by many electronic devices such as laptops, systems, smart phones, etc. In a Wi-Fi setup, a wireless router serves as the communication hub. These networks are extremely limited in range due to low power of transmissions allowing users to connect only within close proximity to a router or signal repeater. Wi-Fi is common in home networking applications which provides portability without any need of cables. Wi-Fi networks need to be secured with passwords for security purposes in order not to be accessed by others.

Wireless Networking (Wi-Fi):
Advantages

Ease of Integration and Convenience - The wireless nature of such networks allows users to access network resources from nearly any convenient location.

Mobility - With the emergence of public wireless networks, users can access the internet even outside their normal working environment.

Expandability - Wireless networks are capable of serving a suddenly-increased number of clients with the existing equipment. In a wired network, additional clients require additional wiring.

Disadvantages

Wireless LANs may not be desirable for a number of reasons.

Radio Frequency transmission and wireless networking signals are subjected to a wide variety of interference including the complex propagation effects that are beyond the control of the network administrator.

Security Problems - Wireless networks may choose to utilize some of the various encryption technologies.

Range will be insufficient for a larger structure - and, in order to increase its range, repeaters or additional access points have to be purchased.

The speed on most wireless networks will be slower than the slowest common wired networks.

Installation of an infrastructure-based wireless network is a complex to set up.

Bluetooth Technology

Bluetooth technology allows you to connect a variety of different electronic devices wirelessly to a system for the transfer and sharing of data and this is the main function of Bluetooth. Cell phones are connected to hands-free earpieces, wireless keyboard, mouse and mike to laptops with the help of Bluetooth as it transmits information from one device to other device. Bluetooth technology has many functions, and it is used most commonly in wireless communications' market.
Features

Bluetooth technology uses radio waves to communicate between devices. Most of these radio waves have a range of 15-50 feet.

According to the official Bluetooth website, Bluetooth uses a low-power signal with a maximum range of 50 feet with sufficient speed to enable transmission of data.

The pairing process identifies and connects any two devices to each other. It also prevents interference from other non-paired Bluetooth devices in the area.

It uses maximum power only when it is required, thus preserving battery life.

ZigBee

ZigBee is a wireless communication standard designed to address the unique needs of low-power, low-cost wireless sensor, and control networks. ZigBee can be used almost anywhere, as it is easy to implement and requires little power to operate. Zigbee has been developed looking into the needs of the communication of data with a simple structure like the data from the sensors.
Features

ZigBee devices are designed for low-power consumption.

ZigBee is used in Commercial Applications like sensing and monitoring applications.

ZigBee uses very low power and extremely long device battery life.

ZigBee gives flexibility to do more with the reliable wireless performance and battery operation.

Types of Wireless Data Transmission

Wireless technology defines the electronic devices that communicate in air without cables using radio frequency signals. Wireless technology is used in a variety of modern device and provides greater mobility. Wireless devices play an important role in voice and Internet communications.
Wireless Router
Wireless routers accepts an incoming Internet connection and sendsthe data as RF signals to other wireless devices that are near to the router. A network set up with a wireless router is called as a Wireless Local Area Network (WLAN).Many routers have built-in security features such as firewalls that help protect devices connected to the router against malicious data such as computer viruses.

A wireless router is used in many houses to connect their computers to the Internet.
Wireless Adapters
Wireless adapters are hardware devices that are installed inside computers which enables wireless connectivity. If a computer does not have a wireless adapter, it will not be able to connect to a router in order to access the Internet. Some computers have wireless adapters built directly into the motherboard, while it is also possible to install stand-alone wireless adapters to add wireless capability to a computer that doesn't have a built-in facility.
Wireless Repeater
A wireless repeater is a wireless networking device that is used to extend the range of a wireless router. A repeater receives wireless signals and amplifies the strength of the signals, and then re-emits them. The strength of the signal can be increased by placing a repeater between the router and the computer connected to the router.
Microwave
Microwave is an effective type of wireless data transmission that transfers information using two separate methods. One method which is used to transmit data through the wireless media of a microwave is the satellite method that transmits information via a satellite that orbits 22,300 miles above the Earth. Stations on the ground send and receive data signals to and from the satellite with a frequency ranging from 11 GHz to 14 GHz and with a transmission speed of 1 Mbps to 10 Mbps. Another method is a terrestrial method, in which two microwave towers with a clear line of sight between them are used ensuring no obstacles to disrupt that line of sight. For the purpose of privacy, it is used often. The frequency of data transmission for terrestrial systems is typically 4 GHz to 6 GHz or 21 GHz to 23 GHz, and the speed is usually 1 megabit per second (Mbps) to 10 Mbps.
Infrared (IR)
Infrared is a media transmission system that transmits data signals through light emitting diodes (LEDs) or Lasers. Infrared is an electromagnetic energy at a wavelength which is longer than that of the red light. The information cannot be travelled through obstacles in an infrared system, but can be inhibited by light. One type of infrared is the point to point system in which transmission is possible between two points limited to a range and line of sight.

The signal frequency to transmit in a point to point system is 100 GHz to 1,000 terahertz (THz), and the speed ranges from 100 Kbps to 16 Mbps. Another method of transmission of infrared includes the broadcast system - and, in this method, a reflective material or a transmission unit amplifies and retransmits a data signal to several other units. The normal frequency of an infrared broadcast system is 100 GHz to 1,000 THz with a limited speed of 1 Mbps.

Types of Wireless Devices
Radio
The radio system is one type of wireless data transmission, and it is a wireless media that transfers data by carrying electromagnetic waves with low frequencies to distant locations through an electrical conductor and an antenna. Ham radio enthusiasts share information and serve as emergency communication aids during disasters with their powerful amateur broadcasting equipment and can even communicate digital data over the radio spectrum.

Citizen's band and maritime radios provide communication services for truckers and sailors. The transmission frequency for information transmitted through a radio system ranges from 10 kilohertz (kHz) to 1 gigahertz (GHz), and the frequencies are regulated by the Federal Communications Commission (FCC).
Wireless Phones
The evolution of cellular networks is enumerated by generations. Many different users communicate across a single frequency band through Cellular and cordless phones. Cellular and cordless phones are two more examples of devices that make use of wireless signals.

Cordless phones have a limited range but cell phones typically have a much larger range than the local wireless networks since cell phone use large telecommunication towers to provide cell phone coverage. Some phones make use of signals from satellites to communicate, similar to Global Positioning System (GSP) devices.
Other Devices
Anything that uses radio signals to communicate can be considered as a wireless device. Common devices such as garage door openers, baby monitors, certain video game consoles and walkie-talkies make use of wireless technology.

Advantages and Disadvantages of Wireless Communications
Advantages

Any information can be conveyed or transmitted quickly and with a high speed.

The Internet can be accessed from anywhere and at anytime without the need to carry cables or wires and it improves easy access and productivity.

Helpful for Doctors, workers and other professionals working in remote areas as they can be in touch with the medical centers through wireless communication.

Emergency situations can be alerted through wireless communication. The affected regions can be provided support with the help of these alerts through wireless communication.

Wireless networks cost less for installation and maintenance.

Disadvantages

A Hacker can easily capture the wireless signals that spread through the air.

It is very important to secure the wireless network so that the information cannot be exploited by unauthorized users, and this also increases the risk of losing data or information.

Thus, Wireless networks are one of the fastest growing technologies in telecommunications market. WiMax, Bluetooth, Wi-Fi, Femtocell and 4G are some of the most significant standards of Wireless technology for the next generations. Radio, Mobiles, Internet, etc., all use technological advancements in wireless data transmission systems that carry invisible electromagnetic waves to transmit data over long distances within a short amount of time. The information provided in this article will be helpful to the viewers.

"What are the New Advanced Technologies in Wireless Communication?"

Get answers from the online tech support now, or contact us by commenting below.
Photo Credits:

# data[].attributes.attachment_link.title
Different Types of Wireless Communication Technologies

# data[].attributes.attachment_link.description
The term wireless refers to the communication or transmission of information over a distance without requiring wires, cables or any other electrical conductors. Wireless communication is one of the important mediums of transmission of data or information to other devices.

# data[].attributes.body
the lecture

# data[].attributes.attachment_link.readable_text
by Chris Woodford. Last updated: June 29, 2020.

Imagine holding out your hand and catching words, pictures, and information passing by. That's more or less what an antenna (sometimes called an aerial) does: it's the metal rod or dish that catches radio waves and turns them into electrical signals feeding into something like a radio or television or a telephone system. Antennas like this are sometimes called receivers. A transmitter is a different kind of antenna that does the opposite job to a receiver: it turns electrical signals into radio waves so they can travel sometimes thousands of kilometers around the Earth or even into space and back. Antennas and transmitters are the key to virtually all forms of modern telecommunication. Let's take a closer look at what they are and how they work!

Photo: The enormous 70m (230ft) Canberra deep dish satellite antenna in Australia. Photo by courtesy of NASA on the Commons.

How antennas work

Suppose you're the boss of a radio station and you want to transmit your programs to the wider world. How do you go about it? You use microphones to capture the sounds of people's voices and turn them into electrical energy. You take that electricity and, loosely speaking, make it flow along a tall metal antenna (boosting it in power many times so it will travel just as far as you need into the world). As the electrons (tiny particles inside atoms) in the electric current wiggle back and forth along the antenna, they create invisible electromagnetic radiation in the form of radio waves. These waves, partly electric and partly magnetic, travel out at the speed of light, taking your radio program with them. What happens when I turn on my radio in my home a few miles away? The radio waves you sent flow through the metal antenna and cause electrons to wiggle back and forth. That generates an electric current-a signal that the electronic components inside my radio turn back into sound I can hear.

Artwork: How a transmitter sends radio waves to a receiver. 1) Electricity flowing into the transmitter antenna makes electrons vibrate up and down it, producing radio waves. 2) The radio waves travel through the air at the speed of light. 3) When the waves arrive at the receiver antenna, they make electrons vibrate inside it. This produces an electric current that recreates the original signal.

Transmitter and receiver antennas are often very similar in design. For example, if you're using something like a satellite phone that can send and receive a video-telephone call to any other place on Earth using space satellites, the signals you transmit and receive all pass through a single satellite dish-a special kind of antenna shaped like a bowl (and technically known as a parabolic reflector, because the dish curves in the shape of a graph called a parabola). Often, though, transmitters and receivers look very different. TV or radio broadcasting antennas are huge masts sometimes stretching hundreds of meters/feet into the air, because they have to send powerful signals over long distances. (One of the ones I tune into regularly, at Sutton Coldfield in England, has a mast 270.5 metres or 887ft high, which is something like 150 tall people standing on top of one another.) But you don't need anything that big on your TV or radio at home: a much smaller antenna will do the job fine.

Waves don't always zap through the air from transmitter to receiver. Depending on what kinds (frequencies) of waves we want to send, how far we want to send them, and when we want to do it, there are actually three different ways in which the waves can travel:

Artwork: How a wave travels from a transmitter to a receiver: 1) By line of sight; 2) By ground wave; 3) Via the ionosphere.

1. As we've already seen, they can shoot by what's called "line of sight", in a straight line-just like a beam of light. In old-fashioned long-distance telephone networks, microwaves were used to carry calls this way between very high communications towers (fiber-optic cables have largely made this obsolete).

2. They can speed round the Earth's curvature in what's known as a ground wave. AM (medium-wave) radio tends to travel this way for short-to-moderate distances. This explains why we can hear radio signals beyond the horizon (when the transmitter and receiver are not within sight of each other).

3. They can shoot up to the sky, bounce off the ionosphere (an electrically charged part of Earth's upper atmosphere), and come back down to the ground again. This effect works best at night, which explains why distant (foreign) AM radio stations are much easier to pick up in the evenings. During the daytime, waves shooting off to the sky are absorbed by lower layers of the ionosphere. At night, that doesn't happen. Instead, higher layers of the ionosphere catch the radio waves and fling them back to Earth-giving us a very effective "sky mirror" that can help to carry radio waves over very long distances.

How long does an antenna have to be?

Photo: Antennas that use line-of-sight communication need to be mounted on high towers, like this. You can see the thin dipoles of the antenna sticking out of the top, but most of what you see here is just the tower that holds the antenna high in the air. Photo by Pierre-Etienne Courtejoie courtesy of US Army.

The simplest antenna is a single piece of metal wire attached to a radio. The first radio I ever built, when I was 11 or 12, was a crystal set with a long loop of copper wire acting as the antenna. I ran the antenna right the way around my bedroom ceiling, so it must have been about 20-30 meters (60-100 ft) long in all!

Most modern transistor radios have at least two antennas. One of them is a long, shiny telescopic rod that pulls out from the case and swivels around for picking up FM (frequency modulation) signals. The other is an antenna inside the case, usually fixed to the main circuit board, and it picks up AM (amplitude modulation) signals. (If you're not sure about the difference between FM and AM, refer to our radio article.)

Why do you need two antennas in a radio? The signals on these different wave bands are carried by radio waves of different frequency and wavelength. Typical AM radio signals have a frequency of 1000 kHz (kilohertz), while typical FM signals are about 100 MHz (megahertz)-so they vibrate about a hundred times faster. Since all radio waves travel at the same speed (the speed of light, which is 300,000 km/s or 186,000 miles per second), AM signals have wavelengths about a hundred times bigger than FM signals. You need two antennas because a single antenna can't pick up such a hugely different range of wavelengths. It's the wavelength (or frequency, if you prefer) of the radio waves you're trying to detect that determines the size and type of the antenna you need to use. Broadly speaking, the length of a simple (rod-type) antenna has to be about half the wavelength of the radio waves you're trying to receive (it's also possible to make antennas that are a quarter of the wavelength, compact miniaturized antennas that are about a tenth the wavelength, and membrane antennas that are even smaller, though we won't go into that here).

The length of the antenna isn't the only thing that affects the wavelengths you're going to pick up; if it were, a radio with a fixed length of antenna would only ever be able to receive one station. The antenna feeds signals into a tuning circuit inside a radio receiver, which is designed to "latch onto" one particular frequency and ignore the rest. The very simplest receiver circuit (like the one you'll find in a crystal radio) is nothing more than a coil of wire, a diode, and a capacitor, and it feeds sounds into an earpiece. The circuit responds (technically, resonates, which means electrically oscillates) at the frequency you're tuned into and discards frequencies higher or lower than this. By adjusting the value of the capacitor, you change the resonant frequency-which tunes your radio to a different station. The antenna's job is to pick up enough energy from passing radio waves to make the circuit resonate at just the right frequency.

AM and FM antennas: the long and short of it

Photo: The AM "loopstick" antenna inside a typical transistor radio is very compact and highly directional. The pink-colored wire that makes up the antenna is wrapped around a thick ferrite core (the black rod). Usually, as you can see here, there are two separate antennas on the same ferrite rod: one for AM (medium-wave) and one for LW (long-wave).

Let's see how it works for FM. If I try to listen to a typical radio broadcast on an FM frequency of 100 MHz (100,000,000 Hz), the waves carrying my program are about 3m (10ft) long. So the ideal antenna is about 1.5m (4ft) or so long, which is roughly the length of a telescopic FM radio antenna when it's fully extended.

Now for AM, the wavelengths are about 100 times greater, so how come you don't need an antenna that's 300m (0.2 miles) long to pick them up? Well you do need a powerful antenna, you just don't know it's there! The AM antenna on the inside of a transistor radio works in a very different way to the FM antenna on the outside. Where an FM antenna picks up the electric part of a radio wave, an AM antenna couples with the magnetic part instead. It's a length of very thin wire (typically several tens of meters) looped anything from a few dozen to a few hundred times around a ferrite (iron-based magnetic) core, which greatly concentrates the magnetic part of the radio signals and produces ("induces") a bigger current in the wire wrapped around them. That means an antenna like this can be really tiny and still pack a punch. Without the ferrite rod, a loop antenna either needs many more turns of wire (so thousands instead of hundreds or dozens) or the loops of wire need to be a lot bigger. That's why external FM antennas for radio sets sometimes take the form of a big loop, maybe 10-20cm (4-8in) in diameter or so.

Artwork: Top: Electromagnetic radio waves consist of vibrating electric waves (blue) and magnetic waves (red) traveling together at the speed of light (black arrow). Bottom: Left: An FM antenna picks up the relatively short wavelength, high-frequency electric part of FM radio waves. Right: An AM ferrite loop antenna picks up and concentrates the magnetic parts of longer wavelength, lower frequency electromagnetic waves.

So far so good, but what about cellphones? How come they need only short and stubby antennas like the one in this photo? Cellphones use radio waves too, also traveling at the speed of light, and with a typical frequency of 800 MHz (roughly ten times greater than FM radio). That means their wavelength is about 10 times shorter than FM radio, so they need an antenna roughly one tenth the size. In smartphones, typically the antenna stretches around the inside of the case. Let's see how that computes: if the frequency is 800MHz, the wavelength is 37.5cm (14.8in), and half the wavelength would be 18cm (7.0in). My current LG smartphone is about 14cm (5.5in) long, so you can see we're in the right sort of ballpark.

Photo: 1) This telescopic FM radio antenna pulls out to a length of about 1-2m (3-6ft or so), which is roughly half the length of the radio waves it's trying to capture. 2) Cellphones have particularly compact antennas. Older ones (like the Motorola on the left) have stubby external antennas or ones that pull out telescopically. (The exposed part of the antenna is the bit my finger is pointing to and there's another part we can't see running around the edge of the circuit board inside the case.) Newer cellphones (like the Nokia model on the right) have longer antennas built completely inside the case.

More types of antennas

The simplest radio antennas are just long straight rods. Many indoor TV antennas take the form of a dipole: a metal rod split into two pieces and folded horizontally so it looks a bit like a person standing straight up with their arms stretched out horizontally. More sophisticated outdoor TV antennas have a number of these dipoles arranged along a central supporting rod. Other designs include circular loops of wire and, of course, parabolic satellite dishes. Why so many different designs? Obviously, the waves arriving at an antenna from a transmitter are exactly the same, no matter what shape and size the antenna happens to be. A different pattern of dipoles will help to concentrate the signal so it's easier to detect. That effect can be increased even more by adding unconnected, "dummy" dipoles, known as directors and reflectors, which bounce more of the signal over to the actual, receiving dipoles. This is equivalent to boosting the signal-and being able to pick up a weaker signal than a simpler antenna.

Artwork: Four common types of antenna (red) and the places where they pick up best (orange): A basic dipole, a folded dipole, a dipole and reflector, and a Yagi. A basic or folded dipole antenna picks up equally well in front of or behind its poles, but poorly at each end. An antenna with a reflector picks up much better on one side than the other, because the reflecting element (the red, dipole-like bar on the left) bounces more signal over to the folded dipole on the right. The Yagi exaggerates this effect even more, picking up a very strong signal on one side and almost no signal anywhere else. It consists of multiple dipoles, reflectors, and directors.

Important properties of antennas

Three features of antennas are particularly important, namely their directionality, gain, and bandwidth.

Directionality

Dipoles are very directional: they pick up incoming radio waves traveling at right angles to them. That's why a TV antenna has to be properly mounted on your home, and facing the correct way, if you're going to get a clear picture. The telescopic antenna on an FM radio is less obviously directional, especially if the signal is strong: if you have it pointed straight upward, it will capture good signals from virtually any direction. The ferrite AM antenna inside a radio is much more directional. Listening to AM, you'll find you need to swivel your radio around until it picks up a really strong signal. (Once you've found the best signal, try turning your radio through exactly 90 degrees and notice how the signal often falls off almost to nothing.)

Although highly directional antennas may seem like a pain, when they're properly aligned, they help to reduce interference from unwanted stations or signals close to the one you're trying to detect. But directionality isn't always a good thing. Think about your cellphone. You want it to be able to receive calls wherever it is in relation to the nearest phone mast, or pick up messages whichever way it happens to be pointing when it's lying in your bag, so a highly directional antenna isn't much good. Similarly for a GPS receiver that tells you where you are using signals from multiple space satellites. Since the signals come from different satellites, in different places in the sky, it follows that they come from different directions, so, again, a highly directional antenna wouldn't be that helpful.

Gain

The gain of an antenna is a very technical measurement but, broadly speaking, boils down to the amount by which it boosts the signal. TVs will often pick up a poor, ghostly signal even without an antenna plugged in. That's because the metal case and other components act as a basic antenna, not focused in any particular direction, and pick up some kind of signal by default. Add a proper directional antenna and you'll gain a much better signal. Gain is measured in decibels (dB), and (as a broad rule of thumb) the bigger the gain the better your reception. In the case of TVs, you get much more gain from a complex outdoor antenna (one with, say, 10-12 dipoles in a parallel "array") than from a simple dipole. All outdoor antennas work better than indoor ones, and window and set-mounted antennas have higher gain and work better than built-in ones.

Bandwidth

An antenna's bandwidth is the range of frequencies (or wavelengths, if you prefer) over which it works effectively. The broader the bandwidth, the greater the range of different radio waves you can pick up. That's helpful for something like television, where you might need to pick up many different channels, but much less useful for telephone, cellphone, or satellite communications where all you're interested in is a very specific radio wave transmission on a fairly narrow frequency band.

Photos: More antennas: 1) The antenna that powers an RFID tag stuck inside a library book. The circuit inside it has no power source: it gets all its energy from the incoming radio waves. 2) The dipole antenna inside a PCMCIA wireless Internet Wi-Fi card. This one works with 2.4GHz radio waves of wavelength 12.5cm, which is why it only needs to be about 6cm long or so.

Who invented antennas?

Artwork: Oliver Lodge's illustration of sending radio waves through space from a transmitter (red) to a receiver (blue) some distance away, taken from his 1898 patent US 609,154: Electric Telegraphy. Courtesy of US Patent and Trademark Office.

There's no easy answer to that question because radio evolved into a useful technology through the second half of the 19th century thanks to the work of quite a few different people-both theoretical scientists and practical experimenters.

Who were these pioneers? Scottish physicist James Clerk Maxwell figured out a theory of radio around 1864, and Heinrich Hertz proved that radio waves really did exist about 20 years later (they were called Hertzian waves in his honor for some time afterward). Several years later, at a meeting in Oxford, England on August 14, 1894, English physicist, Oliver Lodge, demonstrated how radio waves could be used for signalling from one room to another in what he later described (in his 1932 autobiography) as "a very infantile kind of radio-telegraphy." Lodge filed a US patent for "electric telegraphy" on February 1, 1898, describing apparatus for "an operator, by means of what is now known as 'Hertzian-wave telegraphy' to transmit messages across space to any one or more of a number of different individuals in various localities..." Unknown to Lodge at that stage, Guglielmo Marconi was carrying out his own experiments in Italy around the same time-and ultimately proved the better showman: many people think of him as the "inventor of radio" to this day whereas, in truth, he was only one of a group of forward-thinking people who helped turned the science of electromagnetic waves into a practical, world-changing technology.

None of the original radio experiments used transmitters or receivers that we would instantly recognize today. Hertz and Lodge, for example, used a piece of equipment called a spark-gap oscillator: a couple of zinc balls attached to short lengths of copper wire with an air gap in between them. Lodge and Marconi both used Branly coherers ( glass tubes packed with metal filings) for detecting the waves they'd transmitted and received, though Marconi found them "too erratic and unreliable" and eventually designed his own detector. Armed with this new equipment, he carried out systematic experiments into how the height of an antenna affected the distance over which he could transmit a signal.

And the rest, as they say, is history!

Find out more

On this website

Books

Antenna Theory: Analysis and Design by Constantine A. Balanis. Wiley, 2012. A good, general, theoretical introduction aimed at physics and electrical engineering undergraduates. Not really suitable for beginners-and you will need a decent grasp of math.

Small Antennas: Miniaturization Techniques & Applications by John L. Volakis et al. McGraw-Hill, 2010. A look at the theory and practical design of small antennas for cellphones, RFID, and other applications.

Antenna Engineering Handbook by John L. Volakis (ed). McGraw-Hill, 2007. A huge, definitive, theoretical and practical guide to all the common types of antenna.

Antenna Theory and Practice by Rajeswari Chatterjee. New Age International, 2006.

Articles

Tiny Membrane-Based Antennas by Charles Q. Choi. IEEE Spectrum, 22 Aug 2017. Cutting-edge antennas can now be shrunk to 1/000 the length of the wavelength they need to pick up.

Tunable Liquid Metal Antennas for Tuning in to Anything by Alexander Hellemans. IEEE Spectrum, 19 May 2015. What kind of antennas will we need for higher-frequency, shorter-wavelength radio applications in the future?

Apple Patent Cleverly Hides Antenna in Your Keyboard by Christina Bonnington. Wired, 17 August 2011. How Apple keyboards hide wireless antennas under the keys.

Inside Apple's Antenna Design Lab by Brian X. Chen. Wired, 16 July 2010. A tour of Apple's secret antenna-testing laboratory.

Rabbit Ears Perk Up for Free HDTV by Matt Richtel and Jenna Wortham. The New York Times, December 5, 2010. Viewers tired of cable prices are rediscovering the joys of old-fashioned antennas and free TV.

Signal boost for mobile phones: BBC News, 22 April 2008. How Oxford scientists have developed a more sophisticated cellphone antenna.

As Cars Become More Connected, Hiding the Antennas Gets Tougher by Ivan Berger. The New York Times, March 14, 2005..

Hacking with a Pringles tube by Mark Ward, BBC News, 8 March 2002. An interesting news story explaining how hackers have used directional antennas made from Pringles tubes to break into wireless networks.

What you should know about TV antennas by Robert Hertzberg, Popular Science, December 1950. This old article from the Popular Science archives remains a very clear and relevant introduction to antenna design.

Please do NOT copy our articles onto blogs and other websites

Articles from this website are registered at the US Copyright Office. Copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties.

Text copyright © Chris Woodford 2008, 2018. All rights reserved. Full copyright notice and terms of use.

More to explore on our website...

# data[].attributes.attachment_link.description
by Chris Woodford. Last updated: June 29, 2020. Imagine holding out your hand and catching words, pictures, and information passing by. That's more or less what an antenna (sometimes called an aerial) does: it's the metal rod or dish that catches radio waves and turns them into electrical signals feeding into something like a radio or television or a telephone system.

# data[].attributes.headline
How does an antenna convert electrical energy into electromagnetic energy?

# data[].attributes.subject
How does an antenna convert electrical energy into electromagnetic energy?

# data[].attributes.attachment_link.title
How does an antenna convert electrical energy into electromagnetic energy?

# data[].attributes.attachment_link.description
Answer (1 of 5): The ability of antennas to couple electrical signals with free-space electromagnetic radiation is made possible by the fact that accelerating charges radiate electromagnetic energy. Antennas, like the simple dipole antenna below, are driven by an oscillating AC current with a ...

# data[].attributes.body
Technologies of wireless communication
Made with a stroke of good luck
Avatar of Janat Aymaganov
Janat Aymaganov
●
2h

# data[].attributes.attachment_link.readable_text
GPS ( Global Positioning System) Tracking is a system of Satellites, Receivers and complex algorithms that work in sync to provide a location, time sync and velocity for all forms of travel; land, sea, and air.

GPS works at all times, no matter how harsh the weather conditions may be!

What is GPS used for?

GPS has certainly become integrated into the very fiber of our society. Here is a list of the most common platforms GPS is used for:

Do you remember the days of maps? Better yet, MapQuest! I'm a 90's baby so I do remember a bit of that era. In 1996 MapQuest was looking for a way to provide people the ability to get from point A to point B without needing to have a map, which at the time was all people were using to travel to new destinations that they weren't already comfortable traveling to.

A Brief History of GPS:

The first satellites in existence came to be in 1957. While Sputnik was developed by the Russians, the technology evolved in 1959 as US scientists discovered that A satellite in space could be tracked by something called the Doppler Effect.

This effect is best described with the example of a car passing by while honking its horn. You feel the pitch rise as it approaches you , and fade as it passes. For scientists, this meant tracking from the satellite, back to earth was a possibility.

Thus we would be able to track something on the ground given it's varying distance from the satellite!

From the 60's up until the late 90's GPS had mainly been used for Military and Commercial purposes. Although the US government allowed GPS open to the public in the early 80's it took president Al Gore in 1998 to allow additional signals for civilian use. Some cellphones with GPS capabilities were released the following year, and finally we had the birth of modern GPS!

How is GPS used today?

Global Positioning Systems are used in industries like Emergency Response, Entertainment, Health and Fitness, Construction, and Transportation & Logistics!

Those are just a few of the mainstream niches, there are several other micro niches in which GPS can be used to monitor and track.

It has become quite popular in the space that Medallion GPS currently occupy.

We provide a turn-key solution to keep your vehicle tracked at all times. We use state of the art GPS Tracking Devices to help you monitor speed, boundaries, and help keep your vehicle from being burglarized.

How Accurate is GPS?

Simply put: Extremely accurate. There are multitudes of systems in place. For example, Garmin GPS uses a receiver that is accurate from 10 meters! That is incredible precision for something that is orbiting 12,000 miles above earth. Even in terrible weather conditions, you can still track whatever it is that you need track thanks to these receivers.

Understanding the GPS Satellite System:

These satellites orbit us from 12,000 miles above us, like I had previously stated. They are constantly moving and are being driven by small rocket boosters that travel just around 7,000 miles an hour to keep them on track in their orbit. The satellites weigh around 2,000 pounds are measure in at just under 17 feet across with their solar panels extended. These solar powered tracking vehicles have back up batteries included, just in case there is a solar eclipse.

The GPS Signal:

The GPS communicates with a radio signal. At least two low-power radio signals travel by line of sight, which will pass through clouds, glass, plastics, gas, and usually less dense objects like houses or small structures. Note: GPS can not pass through mountains or solid buildings (usually steel or solid concrete). '

There are three types of GPS information:

Pseudorandom Code, which is an ID code that identifies which satellite is transmitting the received information.

Ephemeris Data will determine a satellites position and give information on the health of a satellite, along with the current date and time.

Almanac Data tells a GPS receiver where each GPS satellite is at any given time throughout the day and will show the orbital information for that particular satellite and every other satellite in the system.

What is a Global Navigation Satellite System?

A GPS is actually a global navigation satellite system, meaning it is a satellite navigation system with global coverage. There are two in existence at the moment. NAVSTAR GPS and GLONASS. The NAVSTAR GPS consists of thirty two satellites owned by the US and is the best known and most widely utilized. While the Russian GLONASS is compromised of 28 satellites.

The European Union has a system that is planned to reach full capacity by 2019. That system is called GALILEO. China has a system in the works called BEIDOU with 35 satellites planned, and India is building a system called IRNSS with 7 satellites confirmed.

By 2019 there will be five separate satellite systems in orbit of the earth and even more in the works in the coming years.

GPS vs GNSS?

GPS is a sub system of the GNSS, but the receivers for these two systems are where they differ. Basically, GPS receivers are only capable of reading information from satellites in the GPS satellite network, while GNSS devices can receive information from both GPS and GLONASS at the same time.

GNSS receivers have around sixty satellites available for to determine a location, and while only three satellites are necessary to track a location, accuracy is improved with a larger number of satellites.

All of this comes down to accuracy. The GNSS receivers will record data and plots with more accuracy than a GPS system.

The drawbacks of the GNSS are power consumption are and a higher consumption of bandwidth. All of that pertains to cost.

That is why GPS makes more sense for personal tracking and individual systems.

What is the Next Leap For GPS?

GPS devices don't come without their hiccups. Although GPS has surpassed it's expectations, there are still major improvements on the way! The trend for the next generation will include better protection for signals, making them even more useful for us and users worldwide. Signal Jamming will be a thing of the past and the GPS systems will become even more accurate than they already are!

Where Medallion GPS Vehicle Tracking makes its Way:

We at Medallion sought out to solve a problem. That problem being reliable GPS tracking for your personal vehicle.

As the technology has become available, we have stepped in to make a difference in our global community by providing a solution to those looking to protect their families, and their vehicles.

The Medallion GPS Tracker allows you to utilize this amazing GPS technology to set speed limits, boundary zones, alarm inputs, power starter disable, location updates and grant insurance discounts!

Thanks for reading!

# data[].attributes.attachment_link.description
GPS (Global Positioning System) Tracking is a system of Satellites, Receivers and complex algorithms that work in sync to provide a location. Read through the article to find out how GPS works, it's history, and how it is utilized in your day to day activities!

# data[].attributes.attachment_link.readable_text
Request info

A spectrum analyzer is an instrument that graphically displays signal amplitude against frequency, in the frequency domain. It will show which frequency components are present in a signal and how strong these are.

Not all electrical systems can be characterized properly in the time domain. Circuits like filters, amplifiers, oscillators, mixers, modulators and detectors can be characterized best by their frequency behavior. That frequency behavior is best obtained by observing the electrical signals in the frequency domain. To display the frequency domain, an instrument is needed that can distinguish different frequencies from each other and measure the signal size at the different frequencies. An instrument that can display the frequency domain is the spectrum analyzer.

In the time domain all frequency components of a signal are seen summed together. In the frequency domain, complex signals (signals composed of more than one frequency) are separated into their frequency components, where the amplitude of each component is displayed.

The frequency domain contains information which is not available in the time domain. Therefore the spectrum analyzer has certain advantages compared with an oscilloscope:

With a spectrum analyzer small harmonic distortions on a signal can be displayed better than on an oscilloscope. A sine wave may look good in the time domain, however in the frequency domain the harmonic distortion is visible.

A noise signal may look fully random in the time domain on an oscilloscope, in the frequency domain on a spectrum analyzer it can appear that one frequency is dominantly present.

In the frequency domain it is very simple to determine carrier frequency, modulation frequency, modulation level and modulation distortion from a modulated signal (AM or FM).

Features of the Multi Channel software spectrum analyzer

Figure 1: Spectrum analyzer screen

The spectrum analyzer function in the Multi Channel oscilloscope software uses a Fast Fourier Transform to convert the time domain to the frequency domain. Various different windowing functions are available to minimize the effect of spectral leakage.

Spectrum analyzer graphs

The spectrum analyzer can have one or more graphs, each displaying one or more signals, where each graph can display different parts of a signal. Colors of all items in a graph can be set to any required value. Graph dimensions can be adjusted to any required size, graphs can be located in one single window or in separate windows, which can be located anywhere on the desktop.

Axes can be set to linear or logarithmic.

Cursors are available to make on screen measurements, including determining the Total Harmonic Distortion in a signal. Signals can be given descriptive names and a legend is available to simplify identifying the displayed signals. Text labels can be placed to mark interesting parts of the signal(s).

To reveal all details of the measured signals, unlimited zooming is available in both vertical and horizontal direction. All zoom actions can be undone with an undo zoom function.

Touchscreen friendly toolbars

An instrument toolbar and channel toolbars are available for each detected instrument. The convenient toolbars provide clear buttons for all settings of the instrument and its channels. They show the current settings of the instrument and allow to change all settings. The large buttons are very suitable for touchscreen operation.

The toolbars are fully configurable through the program settings. You can set the button size, add or remove buttons and change the order of the buttons.

Mathematical operations in the spectrum analyzer

Mathematical operations can be performed on the measured data:

Storing spectrum analyzer measurement data

Measurement data can be stored in various different ways:

Saved to disk in various different data file formats

Printed, with customizable layout and colours

Stored as image file, in various common formats

Spectrum analyzer controls

Controlling the spectrum analyzer is done through customizable toolbars, through popup menus and by hotkeys. A quick function toolbar is available for often used functions.

# data[].attributes.attachment_link.description
All TiePie engineering measuring instruments can be used as a USB spectrum analyzer. A spectrum analyzer is an instrument that graphically displays signal amplitude against frequency, in the frequency domain. It will show which frequency components are present in a signal and how strong these are.