Digital Terrestrial Television (DTT) is one of a few ways of receiving Digital Television (DTV) at home. However, in order to receive DTT transmissions and fully realise the benefits available from this new medium the choice of antenna and its positioning needs to be carefully considered.

The antenna (or aerial for us Brits) is the first and arguably the most important link in the chain to receiving a high quality TV signal. If you live in an area of poor reception or do not have the correct type of antenna, then no matter what you do later in the chain, performance is likely to be compromised.

While this article provides an introduction to the antenna issues that directly affect the quality of reception, your local antenna installer should be able to advise which antenna is best suited for your particular location.

Signal Strength

While Digital Terrestrial Television (DTT) can offer improved picture quality over conventional analogue TV by eliminating traditional picture reception problems such as ghosting, a reasonable signal strength is still required.

All or Nothing

A weak analogue TV signal is easily recognised because it will suffer from increased noise or ‘visual snow’. Digital TV however will continue to provide clean reception until a minimum threshold is reached. Beyond this the digital data can no longer be accurately decoded and the output from the TV tuner will cease. A drop of 3dB on a Digital TV or set-top box is enough to make the difference between crystal clear reception and no reception at all.

However, before this point is reached, parts of the digital signal will become lost or corrupted. While the sophisticated error correction algorithms used in DTT decoders can mask these effects to a certain degree, this is second best compared to having the full quality original signal, which is only achieved with a good quality antenna installation.

Frequency Ranges

Digital terrestrial television signals in the UK are transmitted on UHF (Ultra High Frequency) bands IV and V on channels  21 – 68 (471 – 847 MHz). Each channel occupies a bandwidth of 8 MHz, the amount of space required for one traditional analogue TV channel. Historically these channels have been grouped together in different frequency bands:

Matching the Aerial

To extract the maximum signal strength from any received transmissions, the associated antenna needs to be correctly matched to the local transmitter’s frequency band / group and polarisation. In the UK the coloured plastic cap at the end of the antenna indicates which group the antenna is designed for.

Antenna Types

Yagi Antennas

Most TV antennas are of a specific type of antenna called Yagis. A Yagi antenna comprises a number of parallel elements or arms along a rod, a dipole (which collects the actual signal) and a reflector at its rear.

A Yagi antenna is directional and is designed to have a high gain (signal ‘amplification’) to pick up distant signals. The more elements that a Yagi antenna has the higher its gain and therefore the more sensitive it is to weak signals.

Being directional the antenna must be pointed at the transmitter. It will  pick up signals very well from its main direction, but much less so for stations from alternative directions. However, this directionality can be beneficial in rejecting strong, unwanted signals that lie in different directions from the main signal.

Wideband vs Grouped Aerials

Television antennas can be broadly classified into two categories, those chosen for a specific frequency band or channel group and those designed to receive all of the channel groups; wideband.

• Grouped – This antenna is best suited to areas where reception is poor as it can have a higher gain than its wideband counterpart. A grouped antenna usually has a coloured cap denoting which group it belongs to.
• Wideband – This antenna has a lower gain than its comparable grouped antenna and as such is best suited for areas with good to moderate signal strengths.

As Digital TV signals in the UK are transmitted on the same range of channels as those used for analogue TV, it may be possible to receive a digital signal using an existing grouped TV antenna. However, DTT transmissions are sometimes transmitted from more than one group, in which case it is best to consider installing a wideband antenna if you wish to receive all of the available channels reliably.

Antenna Installation

Having chosen the correct antenna, it now needs to be correctly positioned and installed: this is best done by a specialist digital TV antenna installer.

Polarisation

Digital TV signals in the UK are usually transmitted using horizontal polarisation from a main transmitter and vertical polarisation from a repeater transmitter. To maximise the efficiency of the antenna system, the antenna should be aligned to receive the appropriately polarised signals from the local transmitter (i.e. in the case of a horizontally polarised signal the rods of the antenna should be horizontal).

Directivity

The antenna should be directed at the nearest TV transmitter for maximum signal strength as TV signals travel in straight lines.

Location

All antennas should be located away from possible sources of electrical interference such as mains wiring or digital equipment (e.g. computers). It is also preferable not to point the antenna through any metal work or nearby building structures as these will reduce the received signal strength.

In most cases, the higher the antenna can be mounted the better the reception is likely to be. The increased height is also likely to minimise any signal masking effects from local buildings or geographical features.

Indoors

Loft mounted antennas should be mounted away from water tanks and metal pipes. Indoor antennas may also be adversely affected by the building’s construction (e.g. reinforced concrete or steel frames).

Connections

Digital TV antennas are designed with a 75 Ohm output impedance to ensure compatibility with the Digital TV tuner. For optimum performance a 75 Ohm ‘satellite grade’ coaxial cable (type CT100) should be used between the antenna and TV.

All connections should be made using quality connectors, with appropriate precautions being taken for weather proofing of external connections.

Antenna Amplifiers

In cases of very weak reception or where long cable runs are required, an antenna amplifier may be necessary. The amplifier should be mounted as close to the antenna as possible (a masthead amplifier) and matched to the correct local frequency band.

In weak reception areas an amplifier should be considered a ‘last resort’, a higher gain antenna on a taller mast will generally give better results.

Conclusion

Digital Television enables high definition TV to be received at home with a minimum of fuss or capital expenditure. While some Digital TV stations may be received using a standard TV antenna, the best performance will always be achieved by using a properly installed antenna of a type that matches your local frequency range and signal strength conditions.

Remember, if in doubt please contact your local installer for assistance.

As the costs of computer monitors and powerful graphics cards have tumbled year on year, so has the affordability of having multiple displays connected to a PC. It is now no longer just the preserve of a select few blue chip company employees.

Computer monitors have also continued to shrink in size from the traditional, bulky CRTs to the slimmer, more compact flat panel LCDs, as such so has the desk space required to accommodate a multiple monitor set-up.

There is no better time to consider upgrading to a multi-monitor setup; it is now a much more practical proposition than ever before for the average householder to have more than one monitor attached to their home PC.

The Early Days

Back in the early days of the PC everybody used to use the familiar CRT computer monitor. These were rather bulky and  heavy, and offered comparatively small screen sizes relative to their own dimensions.

My first computer monitor, back in the early 1990s, was a meagre 14”. In 2000 I upgraded my PC and opted for a 17” CRT monitor, which I thought was the Bee’s knees at the time compared to my old 14” model.

Flat Panel Monitors

Thankfully technology advances rapidly and within a few years the flat screen LCD monitor became an affordable alternative to the old faithful CRT monitor.

LCD monitors offered similar viewing apertures to CRTs, took a fraction of the desk space and weighed appreciably less. They were also more power efficient than their elder CRT counterparts.

In 2004 I upgraded my old CRT monitor to an Iiyama TFT E431S 17” LCD monitor for the princely sum of £318. In the process I managed to reclaim some valuable desk space; it is surprising how much bigger and uncluttered this made my desk and my office appear.

Dual Monitors

Photo courtesy Dell Inc.

I never planned to have a multi-monitor set-up, but in 2007 a good friend of mine bought me a new PC that came with a monstrous 24” Dell 2407WFP LCD monitor.

A Gift Horse

After upgrading from my old 17” monitor to this huge 24” one you would of thought that I should have been more than satisfied. Under normal circumstances I would. However, I now had a spare monitor that was surplus to requirements, and my new PC came equipped with an Nvidia Quadro FX 3450 graphics card that sported two independent outputs.

How could I not take advantage of this golden opportunity? It would have been silly not to, so I dutifully connected my spare monitor to the spare output of the graphics card and instantly joined the dual monitor club.

Multiple Monitor Upgrade

I had been bitten by the bug!  Having grown accustomed to a multiple monitor system I could no longer resist the temptation and after much consideration I decided to enhance my setup from a humble dual screen system to tri-screen system, thus increasing my virtual desk space by 50%.

Multi-Port Graphics Card

The first problem to overcome was the number of monitors that my current graphics card could support;  two, while my new scheme required three. Unfortunately, due to the age and internal layout of my PC, it was not practical to add an additional graphics card. I therefore required a new graphics card that was capable of supporting at least three independent displays.

Having scoured the Internet, and had a very helpful conversation with the chaps at Nvidia via their online chat system, I settled on the Nvidia Quadro NVS 450 which had four independent DisplayPort connectors. The connectors on my monitors did not support this new display connection format, but fortunately adaptors were readily available for a few pounds a piece.

The new graphics card happened to be more efficient than my old one, but more importantly, was also quieter as it had no fan. This may be of little concern to most people, but as I often record podcasts and other audio projects, any reduction in background noise would be most welcome.

The Third Monitor

The final piece in the jigsaw was to buy the third monitor. Instead of buying just one additional monitor however, I bought two new Dell P170S 17” LCD monitors.

While this helped to preserve the look and symmetry of my system, it also enabled me to use the old LCD monitor for my  Linux server in the garage, replacing an old 15” CRT monitor that got retired to the local skip. Interestingly the two new Dell monitors cost less combined than the single 17” Ilyama monitor that I bought 7 years previously; they call that progress I think.

Restrictive Considerations

I could have undoubtedly chosen larger monitors for my upgrade, but as I use a head mouse to control the PC due to my physical disability, extra wide monitors would have meant that I would have had to virtually twist my head off to get the mouse cursor to the extremities of the screens.

Furthermore, as my audio speakers are mounted on a bookshelf behind the computer monitors, and I do quite a bit of audio work in my study, I did not want the new computer displays to be too tall and therefore shadow the speakers.

As a result of these various considerations, my new system looked like so:

The Benefits

Having used a multiple monitor setup for a few years, I would now find it very restrictive to have to return to a single monitor system. Within a few days of installing my third monitor I was already beginning to wonder how I ever managed to cope with a measly dual monitor system.

Having multiple monitors allows you to spread open documents across your different screens, just  as you spread papers across a normal desk top. This allows for quick and easy referencing across the different documents, instead of having to sift through various open documents on your screen, ultimately improving your efficiency.

If the true paperless office is to have any chance of success in the future, then I think multi-monitor setups will be an essential component.

On the face of it, laying an acoustically reflective surface as a flooring option would seem a particularly stupid idea if editing and recording audio in the room was going to be one of its key uses. However, as is so often the case in life, there were other factors competing in the equation that demanded consideration and therefore necessitated the now irksome wooden floor.

The Need for Change

The choice of “purple” decor in my study was that of the house’s previous owners; not mine. After living with it for a number of years, I decided it was time for a change. As I spend a significant period of time in my study “nerding”, I chose to go for a clean, modern look and feel.

Prior to commencing the project, I measured the area in question and drew a 3D model of its basic layout using Google’s amazingly cool free 3D modelling software: Google SketchUp (see image to right).

Once I had the basic shell constructed, I then played with a few colour schemes and flooring options. My study only has one small window, making it quite dark at the best of times, so the original purple wallpaper was ditched in favour of clean walls painted in a light colour.

Flooring Options

My study was previously carpeted with a dark purple carpet, which while it made the room quite dead sounding, also darkened an already dark room.

I quickly decided on laminated wood as my new flooring of choice for a number of reasons. Firstly, I liked the look of it and felt it would help give the study a contemporary feel and create a more pleasing environment to work in. Secondly, it was light coloured, which would help lift the gloomy impression of the dark room. Finally, it was more durable and easy to clean, which was an important factor, as unfortunately I am confined to a wheelchair following an accident in July 2000.

Despite my convictions that I had made the right choice to use wooden flooring, I remained nervous of its acoustic implications; potentially making the room very reverberant. On an encouraging note however, all of the recording studios and audio editing suites that I have visited in the past all had wooden flooring. So hopefully my decision wouldn’t come back to haunt me.

Secret Plan

Once I’d made the decision to use wooden flooring, I then started to consider the possibility of placing acoustic tiles on the wall directly behind me (when I was sitting at my desk). This was the largest wall surface in the study, so hopefully some large panels would be able to mop up some of the reverberant clutter.

Typical acoustic panels are not the prettiest things in the world, particularly when you’re considering using them in an essentially domestic environment. However, with a little research I discovered that you could get acoustic panels with artwork printed on acoustically transparent fabric. Something that would look good, plus be functional. Result!

The first company I came across (Auralex) had an impressive range of artwork options for their Sonic Print panels, but nothing that really “worked” for me. I eventually settled on a company called GIK Acoustics after having seen a sample image of a guitar spread across 3 panels on their ArtPanel web page. Perfect, particularly as I was a guitarist in a former life.

Another hiccup however was that their standard panels were  2 foot x 4 foot, which would have been a little too tall for the wall I planned to put them on (a dado rail was in the way). Fortunately the guys at GIK Acoustics were very accommodating, and after much deliberation we managed to get the artwork to fit in a manufacturable way on a 2 foot x 3.5 foot frame.

Acoustic Performance

The acoustic art panels contain 2 inch thick mineral wool as the acoustically dampening material. While the manufacturer didn’t have acoustic performance results for the art panels, they did for their 4” panels. The results are apparently very similar, but with the thinner 2” panel not being as effective at the lower frequencies, rolling off at about 250Hz as opposed to 70Hz for the 4” panels. This isn’t too much of an issue for me as most of the audio work I do is speech based, which doesn’t tend to contain a large amount of energy in the low frequencies.

The End Result

When my study decoration project was initially completed (without the acoustic panels) the reverberation times in the room were quite high, making any recordings sound rather echoey. However, when the acoustic panels were installed the difference in sound was amazing; initially it sounded almost like an anechoic chamber to my ears as I’d become so accustomed to the live sounding room.

The acoustic art panels have certainly been very effective in taming the room’s reverberation, probably now down a normal level or even a bit below. I’m sure for true professional standards more would be required, but they’ve done exactly what I wanted and look really cool too.

I think I’ll live with the room as it is for a while before I rush into any decisions regarding further acoustic treatment, but as things stand I can highly recommend acoustic art panels as an ideal solution for a domestic environment: nice artwork plus acoustically functional.

My home network was never planned (it just kind of happened), but since its inception it  grew rapidly to meet my ever expanding needs. For along time it more than met my requirements, but as is inevitable,  I began to demand more of it than it could comfortably provide. So after much deliberation I have just completed a long awaited and much needed upgrade.

My home network originally grew from having a single Laser printer connected directly to my PC, to having my house wired throughout with CAT5e network cable, with every room having potential access to the Internet and a central file server. The file server was responsible for storing all of the household’s data (user files, music and pictures etc.).

My file server (an old 300MHz Compaq) was probably passed its sell by date when I first installed it, but after 5 years of continuous use it was certainly struggling to keep up. This, coupled with the fact that my storage capacity of 100GB was almost maxed out, meant that it really was time to upgrade!

Office Refit

The first part of my network upgrade was instigated by the redecoration and remodelling of my study after much planning with the aid of Google SketchUp (a free and remarkable bit of 3D modelling software).

As part of the reorganisation I wanted to keep my new office space as uncluttered as possible. Prior to this (apart from my main PC) the study played home to the following office equipment to meet my printing and scanning needs:

1. HP LaserJet 5p Laser Printer
2. Intel NetportExpress PRO Print Server
3. Cannon LIDE 50 USB Scanner
4. Epson R300 USB Colour Inkjet Printer

Network Printing

While the little HP Laser printer had given me sterling service over the years (and was in fact the origin of my home network) it was time to retire it. I decided to combine four devices into one with the purchase of a network connected Xerox Phaser 6128MFP-N colour laser printer with integrated scanner.

Apart from saving valuable desk space, this now enabled quick photocopies to be made without having to boot up my desktop PC.

Fast and Furious

As part of the long term plan to upgrade my network, I had previously installed a Gigabit (1Gbps, 1,000Mbps) network switch so that I could transfer large files (such as video) around the network 10 times faster than the standard 100Mbps.

Luckily, my installed cabling was already 1Gbps compatible and my desktop PC had a 1Gbps Ethernet card installed. Up until now however, no other devices on the network were 1Gbps capable. Time to remedy the situation…

Server Upgrade

As my old server was used not only as a general file server, but also as a development web server,  I decided to split the new server system into two; one running Linux for web site development, and a second running Microsoft Windows Home Server with a few terabytes of storage for music, pictures and video.

Windows Home Server

After much deliberation I opted for the HP Data Vault X510 for my Windows Home Server (WHS) box. The particular version that I chose came fitted with two 1.5TB discs giving a potential storage capacity of 3TB; a 30 fold increase over my old system.

This server now holds all of my music, photos, general user files plus a selection of DVDs and videos.

Videos

To store my DVD collection on the new WHS box, I use a free little utility called DVD Shrink. This great little utility rips a DVD in about 15 minutes to a file of about 5GB. The program also enables you to remove the menus and trailers so that you can get straight into a film.

Linux Web Server

The second half of my server upgrade was via a retired Dell PowerEdge 2850 rack server that was kindly donated to me by a friend who luckily happens to own a large UK Internet Service Provider; Zen Internet (thanks Rich!). So please excuse the shameless plug.

The Dell server is a bit of a beast and rather noisy and as such was consigned to the garage. The garage wasn’t originally included in my home network (or its upgrade plan), but with my Google like megalomania taking hold I ran two additional network cables into the garage to facilitate the expansion of my burgeoning data centre.

This server is running a server version of Ubuntu Linux, configured with an Apache web server, PHP and MySQL database server; a configuration often referred to as LAMP (Linux, Apache, MySQL and PHP). I’ve also installed Webmin on the server so that I can remotely administer it via a web browser interface.

Data Protection

Backups

One of the reasons that I chose Windows Home Server, is that every day it automatically backs-up every client computer connected to the network. This works flawlessly with my three client machines being backed up regularly, giving a little extra peace of mind.

Data Redundancy

The WHS box also has folder duplication, so that important files are duplicated on two discs. Thus in the event of a single disc failure, no valuable data should be lost.

While the Linux server data is also protected in a similar manner, with its files being stored on a RAID1 disc array (meaning all data is duplicated across two identical drives), I have also configured it to backup its key data files across the network weekly onto the WHS box for increased protection.

Uninterruptible Power

As I completely rely on my computer systems and their data integrity, I decided to protect the two new servers with Uninterruptble Power Supplies (UPSs). For this function I bought two APC UPSs, both connected to their respective servers via USB so that the servers know when the battery backup is running low, enabling them to shut themselves down in a controlled and safe manner.

Taking Stock

My home network now comprises:

• My Desktop PC
• Laptop (wireless)
• My son’s PC (wireless)
• Network Printer/Scanner
• File Server (music, pictures, videos and files)
• Development Web Server (Linux)
• Music Player (kitchen)
• Music Player (lounge)
• Media Player (bedroom)

Every room in the house now has at least two network connection points, each giving access to:

• Broadband internet 24/7
• Network printing and scanning 
• My entire music collection
• A selection of my videos and DVDs
• All of the family pictures
• Central file storage and backup
• Home intranet

Future Plans

After such an upgrade you’d think that my network would be complete for a while, but it doesn’t take long before the mind starts ticking over and improvements are sought.

The first immediate areas that I think require some attention are:

1. Additional Backup for WHS: This is my weak link for data safety at the moment.
2. New Router: My router presently only supports 11Mbps wireless, so it could really do with upgrading. A new router would also allow me to accept the higher speed ADSL options that are around the corner, which my current router won’t support.

After that, who knows…

Object Oriented Programming represents a paradigm shift away from the traditional modular programming methodologies that have prevailed since the advent of computers. While today’s computer scientists are undoubtedly clever chaps, the intrinsic concepts underpinning Object Oriented Programming were actually considered almost 2,500 years in the dialogues of Plato!

Now, it is extremely doubtful as to whether the architects of Object Orientated Programming (OOP) were aware of these prior concepts, as the stereotypical computer scientist is not normally renowned for his classical education. However, even if they weren’t aware, there does seem to be a remarkable correlation between the thought processes of Plato and the later day software architects, even separated across the millennia.

Ancient Greek Philosophy

Plato was born in Athens, Greece in the year 428 BCE and was tutored by Socrates (often credited as the father of Western philosophy). However, it is Plato, not Socrates, who is arguably the best known of the ancient Greek philosophers (if not of all philosophers), due in large to his profound influence on modern philosophy through his legacy of prolific writings; 35 dialogues and 13 letters.

While Plato’s writings cover many philosophical subjects, it is his radical metaphysical concepts, developed throughout his many dialogues, that are of particular interest in our comparisons with object oriented programming. Fundamentally, it is Plato’s theory of forms that is directly analogous to the foundations of OOP.

Theory of Forms

Throughout his metaphysical discussions, Plato refers to forms as abstract representations that are templates or patterns for real world objects or characteristics of objects.

By way of example, to explain the concept of a form, Plato discusses the concept of beauty. A flower is beautiful and a picture can also be said to be beautiful, but neither are beauty itself. Plato argues that the form  of true beauty exists independently of the objects that have it, as such we may have a notion of perfect beauty, but can never actually experience it first hand.

In Plato’s parlance, a flower is said to partake of the form of beauty. It’s beautiful, but we never see true beauty. The flower is said to be a particular that inherits its qualities from the forms, one of which is beauty.

The form of true beauty is constant and unchanging, whereas a flower may possess beauty for a while, but ultimately looses it when it withers and dies. Being abstract, forms exist independently of the particulars or real world objects that inherit their qualities.

Heavy stuff at the best of times, let alone for over two millennia ago.

Computer Programming

The Traditional Approach

Computer programs are essentially a list of instructions to be followed in a pre described order by a computer; do A, then do B etc.. A bit like following a cooking recipe step by step.

As computers became more advanced, their associated software programmes also became much longer and quite cumbersome. Quite often, a computer would need to run the same bit of code again and again. So, rather than rewrite this bit of code every time it was required, functions or procedures were written as semi-isolated pieces of code that could be called upon whenever they were required. This helped software develop in a modular fashion, with individual modules being responsible for certain computational procedures.

Object Orientated Programming

Object Orientated Programming took modules to the next level, with the modules becoming self contained pieces of code called classes.

A class is a piece of computer program that serves as a template for the creation of an object in exactly the same way that Plato’s forms were abstract philosophical templates for real world objects. The piece of code, or class, is not the object itself, but like the Platonic form, merely a pattern describing what the object will actually be like and what properties it will have when created. Exactly the same concept as Plato’s, just transposed to a different discipline and separated by 2,500 years!

Similar to Plato’s hierarchical system of forms, these classes or templates can be enhanced. Expanded classes can be created, inheriting all the properties of the parent class, but enhancing it with additional properties to create a new “child” class containing all of it’s parents properties, plus a load more of its own:

 1: // Our template or perfect form of a chair

 2: class Chair

 3: {

 4:     // bits of code to define the chair goes in here

 5: }

 6:

 7:

 8: // New template for a type of chair inheriting properties from the perfect chair form

 9: class OfficeChair extends Chair

 10: {

 11:     // bits of EXTRA code for the office chair goes in here 

 12: }

 13:

 14:

 15: // Create an actual object, or particular of the office chair

 16: $objMyOfficeChair = new OfficeChair();

 17:

 18: // Create an another object, or particular of the office chair

 19: $objMyOtherOfficeChair = new OfficeChair();

This is an extremely simplified example, but hopefully the concept of classes and objects and their associated analogies to the Platonic forms and particulars can be seen.

Nothing is New

So, whilst we may think that we’re the cleverest generation to walk on the face of this planet, it may be worth pausing a while to reflect an try to gain a little humility, as we may often just be taking a new slant on old ideas.

Even the bible, in Ecclesiastes 1:9-10, recognises this:

Nothing is new under the sun. Even the thing of which we say, “See, this is new!” has already existed in the ages that preceded us.

Great scientists and thinkers of the past have also acknowledged this fact. Even Isaac Newton paid homage to the inspiration of his predecessors:

“If I have seen a little further it is by standing on the shoulders of Giants.”

Seeking Inspiration

If you’re struggling to come up with an answer to an intransigent problem, or want to find a new way of doing things, perhaps you could do worse than brushing up on your classical education in search of inspiration.

By studying history, even in different disciplines to your own, you may come across ideas that could transpose into your own field of expertise and take you in directions that you would never have dreamed of. They even have a name for the process, they call it the cross fertilisation of ideas.

So, next time you’re a little stuck with a problem, where will you turn to for your inspiration? Plato, Aristotle…

Like many people, I’ve used Microsoft Windows operating systems exclusively for more years than I care to remember. Now, while I’m not about to abandon my comfort blanket entirely, I’ve decided it’s about time to poke my nose out from under the Microsoft blanket and explore the world of Linux; to see what all the fuss is about and if it’s something that I can put to good use.

For the average user, the only serious contender to a Microsoft based desktop PC for regular daily use is an Apple Mac computer with their proprietary operating system. However, if you already have standard PC hardware then Apple’s operating system isn’t really a viable option as it only runs on their hardware.

For the more adventurous however, a third, lesser known alternative exists that also runs on standard desktop PCs: Linux. While Linux is becoming a popular operating system for the new wave of notebook PCs, it’s probably better known as a server based operating system (servers running Linux form much of the backbone of the internet, particularly web servers).

The Linux Alternative

Whilst Linux dates back to 1991, it wasn’t until relatively recently that it became considered as a serious alternative desktop operating system, partly due to its popular Ubuntu version being offered pre-installed by PC manufacturers such as Dell.

Reflecting Linux’s rise in popularity as a desktop alternative, the statistics for my blog last month showed that 3% of visitors to this site were using Linux operating systems (the third most popular operating system of visitors to this blog behind Macintosh [11%] and Windows [85%]).

Now, while I don’t intend to abandon Microsoft as my operating system of choice for my regular desktop PC just yet, I have decided to dip my toe in the Linux pool and experiment setting up a web server on an old PC with Linux. After all, server systems are where Linux flourishes.

The Need for Change

On my home network I currently run Microsoft Windows Server 2000 on an old machine to store my music and pictures, which is accessible by all of the client machines throughout the house. As I develop websites, this machine also acts as a development web server.

However, this server is beginning to creak at the seams and is certainly well passed its sell by date. As most of the websites that I develop end up being hosted on web servers running a version of Linux, it would make sense to have a web server at home running Linux so that I can develop and test web sites in an environment more representative of what they’re likely to be hosted on in the wild.

At this juncture I’ve decided to split my home server system into two. One running Linux for web site development, and a second running Microsoft Home Server with a few terabytes of storage for music, pictures and video.

Ubuntu

Linux comes in many flavours. One version that is gaining a lot of publicity at the moment is Ubuntu, which is available as both desktop and server versions.

The desktop version is essentially built on the server version, but with a graphical user interface added, plus other goodies like the Firefox web browser and the OpenOffice suite of office programs.

As Ubuntu seems very popular, with quite a lot of support for it via internet forums etc., this is my choice of Linux.

If at first you don’t succeed…

I did install Ubuntu (desktop version) on an old machine about six months ago to play with out of curiosity, but never really got too far with it. I eventually gave up, not feeling I wanted to invest the time required to learn a completely new operating system on a whim.

When my present server system started hitting it’s limits I decided that it really was time to decide on a definite course of action for its replacement.

My initial thoughts were to use Microsoft Windows Server 2008, but this is a bit of overkill for what I need, plus pretty expensive. I then stumbled on Microsoft’s Home Server offering. This captured my attention, partly because of its price (about a fifth of its bigger cousin) but also because it’s specifically designed to stream audio and video media and back up all of the home PCs and replicate its data across multiple discs to provide fault tolerance.

Linux for Free

The downside however is that this operating system doesn’t support a web server suitable for the development of websites. Thus, if I want to use Microsoft’s Home Server I will need another server for web development. Linux is the obvious choice for two reasons. Firstly because it’s the operating system that the websites will end up on anyway, and secondly it’s FREE!

So, if I’m going to go this route I thought I’d best have a serious attempt at getting a Linux server running on my old machine to make sure I could get it to do what I wanted it to, before investing in new hardware for my proposed new servers.

If I was going to do it though, this time I was going to do it properly i.e. install the server version of Ubuntu without the graphical user interface, instead of the desktop version. This time I’m going hard core!

If things go to plan, I hope to write a few posts on how I set the system up and the pitfalls encountered.

Fingers crossed, into the abyss we go. Watch this space…

Manufacturers like to develop and retain technologies that gives them a commercial and technological advantage over their competitors. To this end we as consumers have ended up with a collection of competing, but unfortunately technically incompatible, solutions to the same problem; that of storing large amounts of audio on portable audio players.

Thankfully the majority of manufacturers (but by no means all) of these portable audio players have eased our potential incompatibility problems by making sure that their players can play the majority of compressed audio formats that are in common usage today.

So what are these common compressed audio formats, why do we need them and what are the associated problems with having so many different formats?

Why Compress?

Back in the dark ages of computing, not so long ago, computer memory was not so plentiful, or cheap as it is today. As such, storing large amounts of data, such as audio files, was very costly.

As necessity is the mother of invention, the limited quantities of computer memory available prompted the white coated technical boffins to develop fiendishly cunning ways of throwing away most of the audio data from these files, while still retaining a high level of perceived audio quality.

How they do this is rather complicated, but they essentially save space by not storing the bits of the music that we can’t hear. During compression of a 128 kbits/s MP3 file, typically 90% of the audio data is discarded, leaving a file size of one tenth of the original size. This in turn means that your MP3 player is able to store ten times the amount of songs compared to if it had to store the original uncompressed CD data.

MP3

MP3 (MPEG-1 Audio Layer 3) is by far the most well known out of all of the audio compression systems available today, and while it may not be as technologically advanced as some of the newer systems, it is the most widely used and provides perfectly adequate results for moderate bit rates for the majority of people’s requirements.

The major benefit of encoding your audio files in MP3 format is that you are pretty much guaranteed you’ll be able to play your resultant files on almost any modern media player or device. It is for this reason that most podcasts choose to adopt the MP3 format as their preferred compression system.

While most people think that MP3 is a free and open source format, it’s not! There are numerous patents owned by a host of different organisations that are applicable to the MP3 technology. This can make official licensing of MP3 technology for use in encoding software or playback devices quite tortuous. Out of all of the organisations that lay claim to the technology underlying MP3s, the German Fraunhofer Society is probably the most notable.

AAC

AAC (Advanced Audio Coding) is actually part of the MPEG-2 and MPEG-4 specifications and is designed to be a superior technological replacement for the older MP3 format. AAC is designed to provide improved sonic quality and transparency compared to MP3 files encoded at the same bit rate, although this advantage only becomes dominant for lower bit rates (below 128 kbits/s).

AAC is the default format that Apple have adopted for their iPods, iPhone and iTunes and for their iTunes online music store.  Sony has also adopted AAC as the standard audio encoding system for their PlayStation 3 and has been incorporated into their PlayStation Portable and recent Sony Walkman systems. Other companies adopting this format include Nokia and Nintendo (Wii and DSi).

WMA

WMA (Windows Media Audio) is Microsoft’s proprietary audio compression system built into its Windows operating system and is the default compression option used for ripping CDs to your computer using Windows Media Player.

Whilst WMA is a proprietary Microsoft system, the technology has been licensed by numerous third parties meaning that if you’ve ripped your entire CD collection onto your computer’s hard drive in WMA format (as I have), then you have a good chance of being able to play these WMA encoded audio files on a host of compatible devices.

I have a Creative Zen MP3 player, which plays WMA files without any problems and I also have two Netgear MP101 media players at home linked to my home network that can stream music from my server in WMA format.

ATRAC

ATRAC (Adaptive Transform Acoustic Coding) is another proprietary audio compression format, this time developed by Sony, originally for their MiniDisc systems in the early 1990s, but has since been used in the company’s range of portable audio players.

Since its inception, ATRAC’s compression algorithm has been improved over the intervening years, with the newer versions offering improved perceived audio quality over earlier versions for similar bit rates.

Unfortunately, ATRAC encoded files are not widely supported by other manufacturers and as such, if you have a Sony branded audio player and have ripped all of your CD selection into ATRAC files, you’ll be extremely limited as to where else you can play your audio files.

Licence Free

Ogg Vorbis

While the Ogg Vorbis audio compression format is not hugely popular outside of the geeky computer nerd circles, it is worth a brief mention as a number of commercial “MP3  players” support the format. More importantly though is the Ogg Vorbis system is FREE!

There are no patents or licence issues to worry about if you choose to adopt this system, although compatibility with other media playback devices may prove to be an issue.

FLAC

FLAC (Free Lossless Audio Codec) is another audio compression system worth a mention, partly because it’s free (as its name suggests) and partly because it’s lossless.

All of the above compression systems loose some audio quality in their compression process. FLAC does not, but the downside is that the same sort of compression levels are not achievable.

FLAC files tend to be between 40 to 50% the size of the original audio file, which is not that impressive compared to a typical 10% figure of an MP3 file.

Like anything in life, it’s a balancing act. If you can afford the additional storage space required and want original quality audio, then FLAC is the way to go. For the majority of people however, these tiny improvements in audio quality compared to the space saving benefits of any of the above compression formats will not be worth the penalty of compatibility issues.

Summary

While MP3 is the most common and well known of all the audio compression systems, it’s by no means the best. There are a multitude of different audio compression systems available, with just a handful of the most common ones mentioned above.

The choice of compression system can depend on many factors, but for most people, providing the audio quality is reasonably good and the file sizes acceptably small the overriding issue will probably be compatibility.

By now you’ve probably heard of the term “bit rate” used in connection with MP3 tracks and podcasts, you may even know that higher bit rates give better quality audio. However, like most things in life, nothing is simple and we can further complicate the whole bit rate discussion with variable and constant bit rates. So, what are the pros and cons of these constant and variable bit rates?

Choosing a bit rate for a podcast, or an MP3 track, is a bit of a balancing act at the best of times. On the one hand, higher bit rates (variable or constant) give improved audio quality, whilst on the other they lead to bigger file sizes.

Introducing yet another variable into the equation, that of constant or variable bit rates, only serves to confuse the situation even further. What then are the relative pros and cons that may affect your choice of type of bit rate to use?

Balancing Bit Rates

If you’re not familiar with bit rates, then my previous post on What are bit rates? should point you in the right general direction and help to get you started.

In essence, higher bit rates give improved audio quality, no matter whether variable or constant bit rates are used. However, higher bit rates will always lead to larger file sizes, which in turn lead directly to longer download times and require more storage space.

When choosing which bit rate to use for your podcast or MP3 track, you really need to go for the highest bit rate possible, while retaining reasonable file sizes and practical download times.

Accepting the fact that you need to choose the highest practical bit rate you can, which option should you go for next (assuming your encoding software gives you the option) constant or variable bit rates?

Constant Bit Rates

Constant Bit Rates (CBR) are pretty much as their name suggests, where one fixed, or constant bit rate is used for the entire file or track.

However, constant bit rates are not optimal as they waste valuable data bits encoding simple sections of audio, and conversely may not use sufficient data bits on more complex audio passages, resulting in poorer audio quality during these sections.

The more complex audio sections of tracks encoded with a constant bit rate will be of a lower audio quality compared to the more simple sections of audio within the same track, so a suitable bit rate must be chosen that provides sufficient audio quality for the most demanding sections of the audio being encoded.

Constant bit rates are easier and therefore faster to encode compared to variable bit rates and lead to consistent and predictable file sizes. Being an older format, constant bit rates are more compatible with older MP3 players.

Variable Bit Rates

Variable Bit Rates (VBR) are likewise pretty much as their name suggests, where the bit rate may change throughout the file or track being encoded.

Variable bit rate encoding analyses the audio file, adapting the bit rate as it goes to match the complexity of the audio it encounters.

For simple audio passages, the system automatically turn its bit rate down, saving valuable data bits, while retaining the perceived audio quality. Conversely, during more complex passages, the system automatically turns its bit rate up, using more data bits to retain the same level of audio quality.

Using this method, the average audio quality of a file can be increased as the available data bits are used more flexibly to encode the sound data with increased overall accuracy.

When encoding an MP3 track or podcast with the VBR method, the encoding software usually allows you to decide on the overall quality of the resulting track that you desire, after which the system encoder uses the bits required to achieve this defined quality level. Higher quality levels will require more bits.

Compared to constant bit rates, variable bit rates produce smaller file sizes for a given audio quality. However, as the bit rates are variable, it’s difficult to predict the size off these files in advance.

Variable bit rates are harder and therefore slower to encode compared to constant bit rates, as the adaptive encoding process is more complex an processor intensive.

Being a more recent encoding method, some older MP3 players or computer software may not be compatible with variable bit rate encoded MP3 tracks or podcasts.

Constrained Variable Bit Rates

A Constrained Variable Bit Rate (CVBR) is a flavour of variable bit rate, where the maximum bit rate allowed, or the Average Bit Rate (ABR) are predefined.

For example, encoding an audio track with the bit rate set to be an average of 128kbps should produce a resultant audio file of higher perceived quality than the same track of encoded at 128kbps CBR, as the ABR file can use data bits it saved during the simpler passages to add extra data bits (above the 128kbps average) to the more complex passages to improve the overall audio quality.

Which to Use and When

Compatibility

Generally speaking, encoding an MP3 track or podcast using a constant bit rate will be better for the sake of compatibility compared to using a variable bit rate, as some older MP3 players don’t support variable bit rates.

By way of example, in their guidelines for broadcast media, the BBC recommends the use of constant bit rates for their all of their podcasts and downloadable audio files.

Quality

If compatibility isn’t a significant issue for you, then you will probably be better off using a form of variable bit rate of encoding to squeeze the best audio quality that you can out of the available bits.

Whether you choose to use a constrained variable bit rate, so that you can keep a handle on the size of file you’re likely to get, or go for a fully variable bit rate, is entirely up to you.

However, before fixing which method you’re going to use, it may be best to do a few test recordings using different bit rates and bit rate types, before deciding on which suits your purposes best.

In Summary

Attaching speakers to your Hi-Fi system usually only requires a few cables. You wouldn’t think that getting these cables mixed up would present much of a problem would you, providing your music plays back OK and no smoke comes out of the system?

Well, under most circumstances you’d be right, with a simple channel mix up being the most likely probable outcome, but if you have a real knack for getting things back to front, then you could have your speakers wired out-of-phase, which while it won’t do any damage, certainly won’t help you to get the best out of your system.

These potential problems are easy to spot with a few simple tests and luckily the corresponding remedies are equally simple.

Left and Right Tests

In the grand scale of things, getting your left and right speakers mixed up is not a major problem. If your left and right speakers are mixed up, your music will still come out in wonderful stereo (providing of course that you’re listening to a stereo track) it’s just that what should be coming out of the left-hand speaker is actually coming out of the right-hand speaker and vice versa.

Record producers and mix engineers spend weeks mixing and producing an album and as part of the process they will decide where in the mix to place certain instruments. So if you have a favourite track that has an instrument panned (music speak for stereo positioning of sounds) to one side, wouldn’t you prefer to listen to it as the artist intended rather than topsy turvey?

You would? Good.

Then try the following two fairly self explanatory tests on your music system. Listening to the left speaker test, you should hear Winnie’s voice coming out of the left hand speaker (or headphone) only and vice versa for the right speaker test.

Left Speaker Test:

Download audio file (left.mp3)

Right Speaker Test:

Download audio file (right.mp3)

If things don’t go according to plan, then you have either got your speakers wires mixed up (or headphones on the wrong way round), or the audio cabling (shown right) from your playback device to the amplifier crossed over.

Normally audio signal cables (as opposed to speaker cables)  are colour coded with the red plug going to the red socket and white to white at each end of the cable.

You will need to check the wiring of your system, rewiring where necessary and then repeat the two tests to make sure that both channels are working and in the correct order.

The following diagram shows how to wire your speakers to your amplifier:

Balance Test

Now that you’re happy that you have your left and rights sorted out, the next thing to check is your speaker balance.

When you listen to the following test, place your head as centrally as you can between your two speakers; you should hear Winnie coming from the dead centre of your speakers. In this case you are hearing equal amounts of Winnie from both speakers.

Centre Balance Test:

Download audio file (centre.mp3)

If Winnie sounds to be coming either to the left or right of the centre position, you may need to check to see if your amplifier or system has a balance control. If it does, ensure that the balance control is in the centre position.

If after checking the balance control, things still sounds one sided, you may have a more fundamental problem with your system that requires investigation or professional attention. This could be as simple as a dirty connection or a dodgy interconnecting cable, or if things are worse it could be a more ingrained electronic or speaker problem.

Alternatively, if you can’t pin point the sound as definitely coming from the centre, you may have a phasing problem…

Phasing Test

A phasing problem with speakers is very simple to fix, but can significantly degrade your system’s sonic performance.

Trying to describe how out of phase speakers sound is a little difficult unless you’ve experienced it first hand. You’re likely to hear significantly less bass and instead of producing a strong centre image, the sound appears to stay within the speakers, making things sound rather disconnected.

Listen to the following and you should be able to hear the difference for yourself:

Speaker Phase Test:

Download audio file (out-of-phase.mp3)

Or, download: out-of-phase.mp3 [0’ 07”, 128kB]

If the above test sounds perfectly fine, but the previous centre channel test sounded really odd, then your speakers are out of phase.

Fixing the Problem

Thankfully, while the effect can be quite strange, the fix is really simple.

Pick a speaker, but not both, this must only be done on one speaker. Now swap the two wires on the back of the speaker around. Usually the speaker will have two connections; one black (the negative or – connector) and one red (positive or + connector).

That should  be it, job done. Now listen to the centre/balance test and phase test again to confirm that you have everything working hunky dory.

Sit Back and Relax

Now that you have your speakers wired up correctly with your lefts and rights where they should be and no strange out of phase effects, you can lie back, put your feet up and listen to my latest podcast in knowledge of a job well done.

You had no problems; excellent, so there’s no reason not to listen to my latest podcast either! 

Our desire for the illusive paperless office has been around for many years. So, are we any closer to achieving this seemingly impossible dream with recent technological advances, or are we still consigned to emptying the shredder and waste bins every other day?

The concept of the paperless office is certainly nothing new. In 1975, Business Week published an article on “The Office of the Future”. Much of what was predicated in that article has since come true, thanks largely to the release of the now ubiquitous IBM PC in 1981.

However, since the release of the aforementioned PC, rather than decreasing, paper usage in offices doubled in the following 20 years, eventually stabilising around the millennium; hardly a success for the supposed paperless office!

According to the Economist however, since 2001 office paper usage has actually decreased. So, it looks like we’ve finally turned the corner in our paper consumption, but does this mean that we’re close to realising the dream of the paperless office, or do we still have a way to go?

Current Trends

There probably isn’t any primary reason why our paper usage is finally decreasing, but rather many reasons:

• Environmental driving factors are certainly key. We are becoming increasingly aware of our planet’s limited natural resources and are beginning to use them more wisely. Paper comes from trees; so it doesn’t take a rocket scientist to realise that using less paper will mean less trees get cut down.
• Every company tries to minimise its overheads to remain competitive. Reducing paper usage is one such way, as printing on paper costs money.
• The younger generation have been brought up on computers, e-mail and the internet and tend to print less.
• Newer technologies have undoubtedly helped, such as the widespread adoption of broadband internet. Bigger and better monitor technologies, like widescreen LCDs and multiple monitor systems, have made it easier to read and manipulate documents on screen.

Look, No Hands!

My interest in the paperless office was kind of forced upon me. In July 2000 I dived into my neighbour’s swimming pool, breaking my neck and leaving me paralysed from the neck down. Consequently, turning pages or scanning through a book suddenly became quite problematic. If my sanity was to stay intact (some may debate this point), then I clearly had to find alternative ways of doing things.

Scanners and PDFs

Prior to my accident, I was half way through writing my PhD thesis. I had a lot of papers to reference and a logbook full of notes and experimental results. I needed to be able to reference these quickly and easily without having to rely on someone to change pages for me.

Thanks to a cheap scanner and a copy of Adobe Acrobat Professional, I was able to scan all of my key documents and save them in the now common PDF format. I could then grab any of the documents at anytime from my computer’s hard drive.

I now use the scanner and PDF combination on a regular basis to electronically file an array of documents that may need to be referenced in the future; from equipment manuals through to tax returns!

Scanning Alternative

Scanning can be cumbersome or overkill for certain situations. For quick image capture, I have sometimes taken digital photographs of equipment labels for future reference.

Author of the book, The Four Hour Work Week, Tim Ferriss, takes this approach to the next level and takes digital photographs of documents to archive rather than mucking about with a scanner.

How you capture and store information digitally doesn’t really matter, providing it’s quick and convenient and readily accessible at a later date.

Death of the Fax Machine

If the fax machine hasn’t died already, then it’s certainly got an extremely weak pulse and all of it’s relatives are crowded around the bed.

If you need to send a document, just scan it and e-mail it as a PDF attachment. This is essentially all a fax machine does anyway. If the receiving party really needs a paper copy, they can always print one off, although this is obviously not to be encouraged.

Signing Electronic Documents

If someone needs your signature on a document, what’s the difference between signing a paper document and faxing it or attaching your scanned signature to an electronic copy and e-mailing it? None that I can determine, they both get sent down the telephone wire.

So, why not scan your signature and keep it on file somewhere. Next time you need to send a signed document, just paste it in and click send; so much simpler and quicker.

Internet

The internet is an amazing tool to help with the paperless office, but if used unwisely can also conspire against us. How many people regularly print out e-mails as a case in point? They’re electronic, so leave them there; only print them out if absolutely necessary.

Using online banking and direct debits to pay your bills will help reduce your paper consumption as will opting to receive ALL of your bills via e-mail.

Parcel Post

Most delivery companies ask you to sign for parcels on a small PDA carried by the delivery man. Not only does this greatly reduce the amount of paper used, but also allows you to track our parcel’s progress online.

Electronic Books

Electronic books can be downloaded online and read on your computer with free eBook reader software such as Adobe’s Digital Editions. This technology has been available for a while, but unfortunately it’s only recently that publishers have started releasing their offerings (old and new) in this format.

The new Sony eBook Reader allows you to download hundreds of eBooks into one standard paperback sized, lightweight package and read them whenever you want, just like a conventional book. Using new paper like display technology, one charge of the battery can last the equivalent of reading 20 average paperbacks!

The Next Stage?

So, if we’re not quite there yet, what’s stopping us moving forward to the truly paperless office?

There are legal implications relating to the validity of digital signatures on electronic documents, although progress is being made. In the UK, the Law Commission is quoted as saying:

“Digital signatures, scanned manuscript signatures, typing one’s name (or initials), and clicking on a website button are, in our view, all methods of signature which are generally capable of satisfying a statutory signature requirement…”

Paper is comfortable, we’ve grown up with it and it’s hard to kick the habit. Younger generations have less of a problem with this, but it takes time to filter through the system.

If we can manage to wean ourselves off paper, what befits can we look forward to?

• Save space and reduce clutter
• Increase productivity
• Save costs, increase profitability
• Environmentally friendly
• Increase interaction, sharing information online

You may not want to do it all at once, but every little change will have an impact. After all, Rome wasn’t built in a day…