September 20, 2016

The History of Wireless Technology: Wireless or Radio? (Part 2 of 5)

Back in the latter half of the nineteenth century, uses for electricity were just being discovered. By 1880, Thomas Edison had improved his original light bulb to the point that it was a viable product, and early wiring of cities for power had begun. But scientists were discovering that there was a lot more to this new source of energy than first appeared.

In 1888, at the University of Karlsruhe in Germany, a young professor named Heinrich Hertz, proved what other scientists had only suspected; you could send electric "waves" through the air.

However, there hadn't been much work on the practical use of these waves at that point. So, the scientific and technical community just called them "Hertzian waves", since Hertz was the first to prove their existence. But it wasn't long before experimenters were looking at ways of using these new "waves" to do some useful work.

The wired telegraph had been around for a long time. In the United States, Samuel Morse created the first useful wired telegraph as early as 1844. Of course, to make it work, you had to string wires. That was time-consuming and expensive.

Some of the early pioneers of electrical science got the idea that maybe they could get rid of the wires by using these "waves" Hertz had already proven existed to send telegraph code instead. The scientific term that describes the sending of the waves is "radiation". You are "radiating" electricity when you create and send the waves. Once you do that, you have to have a way to "hear" them. The human ear can't hear these waves, so it was necessary to build something to do this. 

In 1890, Edouard Branly, a French physicist, developed a device that would do just that. He called it a "radio-conductuer", since it could receive waves that were being "radiated". However, not everyone used "radiation" or "radio" when discussing this new form of communication.

Gugelielmo Marconi, working in England between 1896 and 1898, showed that you could send signals through the air at considerable distances, and you could send Morse code on these signals.

Marconi called the company that he founded "The Wireless Telegraph and Signal Company" to make sure everyone knew that you didn't need any wires to send Morse code by this method. So, "wireless" became a common term for this new form of communication in England.

However, some technical people began to gravitate more towards using the term "radio" in place of the term "wireless". In the January 21, 1898 issue of The Electrician (London), a letter from a reader suggested that the term "radio-telegraphy" might be preferable to "wireless-telegraphy". 

In 1904, the British Post Office, which was the branch of the government that sent telegrams, specified that any telegram sent by an over-the-air method had to insure that "...the word "Radio"... is send in the Service Instructions". 

Meanwhile, in 1906, in Berlin, Germany, the Berlin Radiotelegraph Convention included a Service Regulation specifying that "Radiotelegrams shall show in the preamble that the service is 'Radio'", again to distinguish it from the use of wired telegraphs.

There were some holdouts on this, however. Electrical engineer William Maver, Jr., who, in the preface to his 1910 book "Wireless Telegraphy and Telephony", said that he intended to stay with the older term "wireless". Apparently, he was a traditionalist.

Between 1907 and 1920, "radio" and "wireless" were used to describe the new communication method interchangeably. In the United States, Lee de Forest, an early researcher who is credited with developing some of the first tubes used in receivers, called it "radio". This led to a general migration to the term "radio" in the United States. However, in England and Europe, "wireless" was still widely used.

It wasn't until the early years of broadcasting, around 1920, that the term "radio" began to become the more common term used everywhere. In 1923, the British Broadcasting Company (BBC) launched it's magazine devoted to broadcasting, called "Radio Times" (still in publication today). The BBC's decision to use "radio" pretty much put "wireless" aside. In most places around the world, "radios" became an understood term for over-the-air broadcasting and communications.

That is, until the rise of computer networks in the latter half of the 20th century.

Just like the early telegraph signals that were sent in the nineteenth century, early computer networking was done using wires, or, more properly, cables. Many times, the choice of cabling was either a coaxial cable or a twisted-pair cable. (Today, the bulk of the wired networking is done with twisted-pair cables.)

As computer networking evolved, it was easy to see that the need for over-the-air, un-cabled networks would provide a lot of convenience and solve a lot of problems. Just like what happened in the early 1900's with Morse code communications, scientists and technologists knew that, somehow, a way would be found to get rid of the cables.

Some early over-the-air computer communications with microwave systems was successful, due to the wide-band capability of these systems. Because of the bandwidth available at the higher microwave frequencies, these systems could transmit a large amount of data at a fast rate. Satellites, too, had this advantage due to the frequencies at which they operate. Uplinks and downlinks could replace terrestrial cable systems, including those that ran under oceans.

Finally, regulatory agencies created radio bands which were originally intended for use in "Industrial, Scientific and Medical" research, appropriately called ISM bands. Hardware designed to operate in these bands did not require users to obtain licenses. This opened the door to allow unwired computer networking systems to be implanted without users having to comply with complex regulatory filings.

And so, as these systems became more common, the term "wireless" arose again, due mainly to the fact that the use of these bands allowed elimination of the wires (or again, more properly, cables) needed to tie computer systems together.

So, now we're back to defining these systems as "wireless", just like in the early part of the last century. To quote baseball's Yogi Berra, "It's déjà vu, all over again".

Interestingly enough, today one major technical group defines wireless networking as: "Using radio, microwaves, etc. as opposed to cables to transmit computer networking signals". 

"Wireless" or "radio", the term used is less important than the ability to perform the work needed to get data across given distances. Call it what you will, it has revolutionized our ability to connect computers into a network and contributed greatly to the rise of the world-wide web.

Timeline: Radio vs Wireless

In part 3 of our series, we'll look at some of the requirements necessary to make radio/wireless systems capable of sending and receiving data without interfering with each other, as well as touch on the software systems that create these results.



Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com



September 16, 2016

ROAD REPORT: Space...the Wireless Frontier

Ok...time to get out your Star Trek communicator pin, your Mr. Spock ears and Klingon mask and sash. Clear-Com brings us to the edge of space exploration - or at least to the training centers.



We start with a 6 million gallon pool that's bigger than a football field. A major space agency uses this pool to train astronauts from around the world, simulating the weightless conditions of working in low earth orbit.

The astronaut trainees put on their space suits and, through an umbilical of tubes and cables to the poolside tender positions, get their air, medical telemetry and communication needs. They all connect via standard 4-wire connections (line-level inputs and outputs to a matrix port in the main control server room). There are controllers at poolside and controllers simulating Mission Control Center-like consoles that guide the trainees and the scuba diver assistants through the paces of their exercises. A beautiful techno-ballet in the slow motion world of the underwater, weightlessness of simulation training.

Why Do Astronauts Use Training Pools?


Imagine you are all suited up in your cool, high-tech space suit. HAL900 has opened the Pod Bay door. You stand on the step, taking in the unbelievable view and....you step off into the abyss to do your spacewalk in order to fix an antenna on the other side of the Space Station. In the weightlessness of space, you turn your wrench to tighten the bolt on the antenna. But, if you haven't practiced your task while weightless, just as you move your body to turn the bolt....it's quite possible you might also turn the whole Space Station! Didn't know your own strength, did you?



Well, this training is why the astronauts do simulation training at the pool. Using Clear-Com's FreeSpeak II wireless and Eclipse HX digital matrix systems, the team is able to coordinate communications between the Control Room simulations, the Dive Boss' station, the medical team (who constantly monitor the astronauts' and assistant divers' vitals), and the technical coordinators, while maintaining clear and open lines of communications. This way, the task of learning how to work in weightless conditions can be run in a smooth, efficient and safe manner. 



Wireless Work Flow

Wireless communication can be very persnickety, as we all know. In this decade, we are seeing the loss of wide swaths of the narrow UHF spectrum. As these bands are sold off to the highest bidder, we are all left looking for new places to use our small signals for mics, comms and IFB (interruptible fold back for talent and in-ear monitors). 



Clear-Com's FreeSpeak II plays a big part in the workflow here. First off, the 1.9 GHz model keeps the comms well out of the way of other frequency traffic, both in the remaining UHF and the now very crowded 2.4 GHz spectrum. With that said, with the deployment of Frequency Hopping Spread Spectrum (FHSS) technology and recent Clear-Com innovations, the use of 2.4 GHz wireless systems are becoming more attractive. The FreeSpeak II 2.4 GHz has been chosen for some of these training facilities because of the redundancy transmission of the FHSS scheme, which helps with the immensity of the room and reflective nature of the architecture and the huge water surface reflectiveness. 



The FreeSpeak II solution uses a deployment of an array of Transceiver Antennas that can service up to 5 beltpacks per transceiver. These are then spread out around the needed coverage area and the beltpacks hand-off from one antenna to another as the users move about the covered areas. Their seamless hand-off is clean and has a killer clear sound. The high quality spectrum of audio makes the FreeSpeak the best sounding multi-channel communication system around. And when using the matrix integration card option, as the large training pool area has, it makes it possible for any intercom panel in the facility to directly talk with any and every beltpack user, and vice versa. When programming the FreeSpeak II through the Eclipse HX's EHX software, it's just a simple drag and drop function. BINGO...you're all set to get to work. When using this integrated method, the beltpacks can do just about anything that the wired matrix user panels can do. If there's a telephone interface in the matrix, the FreeSpeak II beltpacks can be programmed to make a telephone call (including speed dial to the actual destination phone number) or trigger relays or GPI's with the touch of a button.


The award-winning audio clarity of the FreeSpeak II wireless system makes for crisp and clear communications, in an environment where it's most vital, like simulated training courses for astronauts going into space. These expert technicians need a system that can adapt to their unique workflow and one that they can trust will work in any environment. Perhaps, one day......even in space. 



Rom Rosenblum has always been a capable, yet rebellious audio-guy. Originally in the music recording business as an engineer, with a long Emmy Award winning career in live TV broadcasting, Rom worships at the altar of All Things Audio. As one of the Applications Engineers at Clear-Com, he works as a catch-all fixer for folks who need tech support, commissioning, systems design, product development, and sales support.







August 15, 2016

Wi-Fi: What Does the Name Mean and How Does it Work? (Part 1 of 5)



WHAT IS Wi-Fi? 

Unless you've spent the last few years inhabiting a cave, you've probably heard the term "Wi-Fi" (or maybe "WiFi", which is an alternate spelling). It's become one of those common "buzzword" expressions, like "cellular", or "mobile", or "social media".

But just exactly how do we define Wi-Fi? We all know what its most basic use is; it allows us to connect to the Internet without having to plug a cable into whatever we're using to connect. 

What the name actually means, where it came from, and how the technology works are things that many people don't fully understand. What we hope to achieve in this series of posts is some enlightenment on these subjects.

Wi-Fi IS NOT AN ACRONYM

The original standard for all wireless capability was developed from the Institute of Electrical and Electronics Engineers, or IEEE, and was originally published in 1999. The full-blown name for the important part of this standard is "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications".

As time went by, it became obvious that there were certain products that wouldn't work with other products. Many times this was because the wireless modem in one device worked differently than the one in the device that it was trying to connect to. This was due to the face that the IEEE had no way to test different manufactures' equipment for compliance with the standards it had published.

So, thus was created a non-profit organization called the Wireless Ethernet Compatibility Alliance. It was formed to help ensure that wireless Internet products conform to certain interoperability standards. The idea was to make certain that one company's "box" could talk to another company's "box". 

However, after the Alliance had been in existence for a while, a non-technical issue arose. This was that the name of both the Alliance, and the standard, were considered too long and too clumsy.

Some thought was given to using the initials, WECA, a shortened version of the Alliance's name, but that was only part of the problem.

The bigger problem was that the standard's name had become known as the "IEEE 802.11b Direct Sequence". As one founding member of the Alliance commented, "We needed something a little catchier than that". The name just didn't have that "ring" to it to make it memorable. 

So, the Alliance hired a consulting company, called Interbrand, to help them come up with something that was more memorable, and would still be descriptive enough to explain the standard, and the work that the committee was doing. 

The result was the term "Wi-Fi", and the new name for the Wireless Ethernet Compatibility Alliance became the Wi-Fi Alliance. Although some members of the Alliance were not sure that this was a good idea, since the name didn't have a specific literal explanation, the consensus was that this satisfied all the requirements. It was easy to spell, easy to remember, and had the potential to become one of the "buzzwords" that populate our conversations today.

NOW THAT WE'VE NAMED IT, HOW DOES IT WORK?

Because of the speed, reliability, and usefulness of Wi-Fi, we sometimes forget there is a single most basic concept to it; a radio frequency signal. (If you're familiar with the OSI computer networking model, this is the "physical layer")

When you get on the other side of all the software, the protocols, the modulation techniques and all the other stuff involved in Wi-Fi, you can boil the whole thing down to the fact that Wi-Fi consists of a series of computer-controlled two-way radios. That might sound almost too simple, but really, within the laws of physics, that's all there is.

Of course, some people will balk at the term "radio" and insist that non-wired data communications should be referred to as "wireless". For right now, just keep in mind that radio waves being sent through the air from one device to another are what allows information to be transferred in a Wi-Fi environment.

Since the real purpose of Wi-Fi was to provide a way to transfer the same type of information that can be sent through a wired network, such as a 100BASE-T Ethernet network, some challenges faced the early developers. 

First off, all the protocols, control codes, and other metadata that a wired network uses had to be put onto the radio signals. Also, all this information had to flow in both directions, that is, to and from each network node. When you include the data itself, this means sending and receiving a lot of information.

In a wired environment, you don't have to constantly turn on and off the radio waves in the devices. With radio communications, this usually has to be done because two radio waves on the same frequency, at the same time, will interfere with each other.

Trouble is, this can be very time-consuming. It can slow data transfer down significantly. In data communications, speed is of the essence.

So, how do you overcome this challenge? What can you do to a radio wave to make it work compatibly with other radio waves right next to it, all around it, or even on its very own frequency?

In Part 2 of our series, we'll explore some of the ways to overcome these issues, and take a look at the history and definitions of the words "wireless" and "radio".




Paul Black is a freelance writer and broadcast engineer in Northern California. He holds a Certified Professional Broadcast Engineer certification from the Society of Broadcast Engineers and an FCC Lifetime General Class Operator License. He is a licensed amateur radio operator (call sign N6BBZ) and has worked for several broadcast companies, including Bonneville Broadcasting, RKO General Broadcasting, and CBS Television. Visit his website at www.paulblackcopy.com