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DTT
Digital Terrestrial Television
THE FUTURE OF TELEVISION!

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Digital Terrestrial Television - The future of television is with us

All analogue television in the UK is being switched off between November 2007 and October 2012

DIGITAL SWITCHOVER BY ITV REGION

Borders:  Nov 2007 - July 2009

 
South West England: July - Sept 2009

Wales: Sept 2009 - March 2010

North West (Granada): December 2009

West (HTV):  April 2010

Scotland (Grampian):  May - Oct 2010

Scotland (Scottish):  Oct 2010 - March 2011

Channel Islands:  November 2010

Yorkshire:   May - September 2011

Central England:  March - October 2011

East Anglia:   April - June 2011

Southern England:  February - June 2012

London:   April 2012

South East England:  May - June 2012

North East England:   September 2012

Ulster:   October 2012

TV viewers in Wales, the Borders and the south west ITV regions were the first to have their analogue television transmitters switched off as part of the UK-wide timetable for Digital Switch Over "DSO".  After an initial test where the television transmitter at Ferryside was switched over to digital-only television in 2005, the Whitehaven transmitter, in the Border region, was the vanguard for full digital switch over. Whitehaven DSO was in November 2007 with the Selkirk transmitter following in November 2008 and Caldbeck and Douglas in July 2009.

Media regulator Ofcom set the timetable that will see the UK will be fully digital by 2013. This just misses the UK Government's target date of 2012. The digital switch over will be accomplished region by region.

The phasing in of a digital-only service would end with the analogue signal being switched off in the Ulster region in 2013.  Initially digital terrestrial signals could reach 73% of UK households,  at lower power than after "DSO", with a significant increase in coverage not possible until analogue television is shut down.

To continue to receive television programmes after the switch-off of the analogue signal, viewers would have to connect all their TV sets to a digital TV service, via Freeview, cable or satellite.

In most cases, that would require them to buy a digital television receiver box (Set Top Box) and possibly to upgrade their aerial.


Each region would be converted over a period of several months, giving households time to switch to a digital terrestrial (Freeview), cable, or digital satellite service.


[ As a personal aside, I cannot understand why the UK government has been faffing about for years over DSO, and continues with even more faffing about by taking six full years to achieve digital-switch-over on a piecemeal, region by region basis, lengthening the period of viewer confusion!

Denmark and the United States of America performed DSO on one clear date. The USA switched off ALL main, high power, analogue television transmitters on 12th June 2009, leaving everyone with just the digital signals. That seems far simpler. I appreciate the huge engineering challenge in equipping all the transmitters for digital, but then maybe the UK should have started preparations earlier, rather than ending the process four years behind the USA and other countries!!
In fact Germany* and Switzerland had made the switch to digital by the end of 2008, while Britain still had five more years of faffing to endure.]
* except one transmitter

TV Regions


Some of the best Digital Switch Over information can be found on these web sites:



MB21 - Mike Brown's TV resource -
http://tx.mb21.co.uk/dso

Digital UK - clear information for TV viewers -  http://www.digitaluk.co.uk

FREEVIEW - official site - http://www.freeview.co.uk

FREEVIEW - postcode checker - http://www.freeview.co.uk/availability

UK Free TV - general free TV information - http://www.ukfree.tv

BBC - digital reception advice - http://www.bbc.co.uk/reception/digitaltv/index.shtml

Digital TV Group - postcode reception checker - http://www.dtg.org.uk/industry/coverage.html

DTG - Details of television channels on each multiplex -
http://www.dtg.org.uk/industry/dtt_channels.html

Digital TV Group - with sections for consumers & industry -
http://www.dtg.org.uk

Digital TV (government site)
- http://www.digitaltelevision.gov.uk

Arqiva - the UK's transmission provider - http://www.arqiva.com

Ofcom - the regulator's DSO page - http://www.ofcom.org.uk/research/tv/reports/dsoind/


Engineer
                  Andy Elston at the Crystal Palace transmission site
Tuning out:

The digital switchover signalling the end of an era for television's analogue transmitter


[The Crystal Palace London digital television switchover]

Daily Mail article By Robert Hardman  - 17th April 2012

(Extract): [Just after midnight on the 18th April 2012] ....so late, in fact, that most of us will be in bed – an engineer called Andy Elston will walk into a concrete bunker in South London and press a button marked ‘off’ on the side of several white steel cabinets. As these machines fall silent, Andy will walk next door and press the ‘on’ button to start up what looks like a brand new ship’s engine. And up above - at London’s highest point - a stack of metal dishes will start pumping out an entirely new digital television signal. Even though there will be nothing to see and most of us will be asleep, this moment has already been hailed as the ‘most important moment’ in modern British broadcasting history. Andy Elston, take a bow.

The great £630 million UK switch-over (from analogue to digital television) has already happened in several regions across Britain. And it will not be until October [2012] that the last old-style analogue transmitter is finally disconnected (in Northern Ireland).
ut, as far as the industry is concerned, the most important moment is tonight when the Crystal Palace Tower changes its tune. Because Crystal Palace, perched above south London suburbia, is to television and radio broadcasting what Wembley is to football.

Britain actually has a total of 1,154 television transmitters reaching 60 million people, from the Outer Hebrides to Bodmin Moor. All of them either have been, or are about to be, converted to the new technology. But this single monster is by far the most important because it accounts for a fifth of the population all by itself. It was from here that colour television first took flight in 1967, from here that HD television was transmitted for the first time in 2009.

So it will be the end of one era and the start of another at one of Britain’s most conspicuous - and well-connected - landmarks. After all, it is from Crystal Palace that the Queen and her Government receive everything from Coronation Street to Question Time. If radio transmitters were awarded royal warrants, this one would have a handful.

Read the full article : http://www.dailymail.co.uk/news/article-2130899/The-digital-switchover-signalling-end-era-televisions-analogue-transmitter.html    The photograph above shows Engineer Andy Elston at the Crystal Palace transmission site.  -   Daily Mail 17th April 2012

Andy
                Elston in charge of analogue switch off and Digital
                Switch Over
Andy Elston in charge of the Crystal Palace transmitters at Digital Switch Over
------------------------------------------------------------------------------------------------------------------------------------------------

The end of
                Channel Four analogue television from Crystal Palace
The end of Channel Four analogue television from Crystal Palace
ETP1 test pattern
------------------------------------------------------------------------------------------------------------------------------------------------


HOW TO RECEIVE FREE DIGITAL TELEVISION


By the end of 2005 about 70 to 75 percent of households could receive around thirty channels of free to view Digital Television from FREEVIEW via an ordinary roof mounted television aerial  and an Set Top Box (STB).  A set top box is very simple to install and operate. The set-up procedure is generally fully automatic with little need for any technical knowledge.

Installation usually takes less than 5 minutes, with the box auto tuning all the available multiplexes and TV channels. Day to day use is also very simple.

Goodmans GDB300HD
Goodmans GDB300HD Freeview Set Top Box
Provides access to all Freeview channels including High Definition (HD) channels.


The 75 percent coverage of FREEVIEW will be expanded to near universal population coverage between 2008 and 2012 as the analogue transmitters are switched off thereby allowing additional digital terrestrial television transmitters to be switched on and powers to be increased at all the existing DTT transmitters. New Freeview HD (high definition) broadcasts will also be available.


A SUITABLE TV AERIAL

Apart from a set top box like the one shown above, viewers will need a suitable tv aerial.  In many cases an existing tv aerial will be sufficient;  As long as existing analogue pictures are clear and free from snow, noise and interference (and that DTT - digital television - is transmitted from the transmitter that the aerial is pointing towards) then viewers could reasonably expect to be able to receive the many digital channel available from FREEVIEW. Other commercial and pay TV channels may also be available.

If the pictures were a bit snowy and noisy on analogue (indicating that the aerial is poor anyway) there is a good chance that digital reception will not be possible and that an aerial upgrade will be required.  Additionally if the DTT multiplexes are transmitted in different UHF channel groupings than the local analogue channels (more about this below) it may be that the existing aerial may need to be replaced with an aerial of a more suitable group or a 'wideband' aerial (more below). However the transmission providers have attempted, wherever possible, to keep the new digital transmissions within the groupings previously used by the old analogue channels.

A  word of caution about aerial installers: 

There is no such thing as a "Digital Aerial". As long as the aerial is in good condition and of the correct type - called the "group" - it will receive analogue and digital television equally well - assuming that the local transmitter is providing digital television coverage in the area.

There are many good installers of course, but there are very many cowboys who are trying to leap on the digital switch-over bandwagon and sell inappropriate aerials, badly fitted and with cheap low quality coaxial cable and charge vastly inflated prices! If possible use a CAI approved installer http://www.cai.org.uk/

For unbiased and accurate information about digital television and television aerials do look at the PARAS website - Professional Aerial Riggers Against the Sharks:  http://www.paras.org.uk/

Freeview coverage can be indicated by performing the postcode check here: http://www.freeview.co.uk/availability  (It does seem to be designed to be a little pessimistic, possibly so that people's hopes are not unduly raised while the Freeview signals are a lower power than they will be after 'digital switch-over'.




INTERFERENCE TO TERRESTRIAL DIGITAL / FREEVIEW TELEVISION RECEPTION -
THE 800MHz  - 4G - Spectrum Sell Off Problem

TVs facing black-out from 4G interference, claims Freeview   -    News Story from The Scotsman June 16th 2012

Millions may be affected by effects of internet signal, says Claire Smith:

THOUSANDS of people across Scotland could face loss of television channels, fuzzy pictures or even lose reception altogether because of the roll-out of 4G internet, says Freeview. New figures estimate 185,474 households in Scotland could be affected – with 2.1 million across the UK expected to face a loss of signal because of interference caused by 4G. The 4G network, which will mean faster smartphone internet access, is due to be rolled out across the UK from next year – however, because the frequency is close to that used by by free digital channels, it is expected to cause difficulties.

Although the Department of Culture, Media and Sport has earmarked £180 million to pay for adapting televisions where the signal is affected, Freeview says this may not be enough. According to figures obtained by the company, fitting filters to televisions to restore picture quality and lost channels is likely to cost at least twice what the government has earmarked to pay for it. Furthermore, the government has only offered to provide a filter for one TV in each affected household – meaning consumers themselves will have to pay to adapt any further TV sets.

Representatives of Freeview, which provides 50 free channels to 20 million homes across the UK, are meeting with culture and creative industries minister Ed Vaisey on Monday to demand further action. Ilse Howling, managing director of Freeview, said: “The government has committed to recouping the cost of protecting viewers from interference using proceeds from the 4G mobile auction. However, this will still leave viewers to bear a substantial proportion of the cost. The mobile phone operators will be the ultimate beneficiaries of this new service, and we believe that they should pay to mitigate the television interference according to the ‘polluter pays’ principle.

“Free, quality TV is part of Scotland’s DNA. Almost 90 per cent of Freeview homes and 75 per cent of second set homes would be unhappy if Freeview were no longer available.” A DCMS spokesperson said: “We have announced a £180 million help scheme, to be funded by the winning 800MHz licensees, to deliver solutions to TV interference resulting from 4G mobile services. For most households, fitting a filter provided by the scheme will solve the problem, but there is funding for more complex cases.

“Ofcom is considering responses to their consultation on how the help scheme should work and we will listen to any concerns raised by them, or by Freeview, in planning next steps”

A Which? spokesperson said: “The 2.3 million Freeview households that could be affected by the new 4G networks should not have to pay to combat interference. The government has said every affected household will receive one free filter, but for some households the installation costs could prove expensive. The government must be clearer about the level of support available to these households, and ensure the costs fall primarily to the mobile operators and not the taxpayer or individual consumers.”

Earlier this year, Orange and T Mobile launched a joint campaign under the name Everything Everywhere to lobby for the government to speed up the roll-out of 4G across the UK.

Background:

Traditionally in Britain the frequencies from 470MHz to 862 MHz have been used for domestic, terrestrial television broadcasting using both analogue (BBC 1, BBC 2, ITV, Channel 4) and digital (Freeview) methods: This range of frequencies provides TV channels from 21 to 69. It should be noted that channel 36 is used for radar, channel 38 is used for radio astronomy and channel 69 is used for licensed and 'licence exempt' wireless microphones.

It has been announced that channels 31–40 (600 MHz) and 63–68 (800 MHz) are to be sold off or auctioned and thus may be made available for other uses, under the supervision of the UK "regulator" Ofcom. This is the so called 4G sell off.
http://www.scotsman.com

For more information please see:  Let's Be Clear  -  https://at800.tv/

The 800MHz Sell Off:

By 2013 the UK all analogue television transmissions will have been switched off. Digital Switch Over ("DSO") will have been completed. Rather than using all of the UHF band that was previously reserved for television broadcasting for digital terrestrial television post 'DSO' the government department BIS and Ofcom decided to sell off some of the frequencies for other uses: The "800MHz Sell Off ". The spectrum space, once used for your television channels will be sold off to the highest bidder - probably to mobile networks.

The close proximity of the frequencies to the domestic television channels will mean that once the new sold-off frequencies are being used up to around 3/4 of a million homes will experience interference to their television reception and may lose reception altogether.

What a great idea !

Ofcom and BIS between them have proved themselves time and again to be Unfit For Purpose as far as technically sound spectrum management is concerned. Proper radio spectrum management should ensure that interference is eliminated or at least minimized - not as is the case here seemingly encourage by the so-called regulator Ofcom.

Ofcom and BIS, remember, are those august bodies that continue to allow the proliferation of Power Line Networking systems that transmit interference over EVERY radio frequency from HF to VHF - that is many and various licensed radio services that include your own FM and DAB radio, also business radio ("PMR") such as taxi companies etc, not to mention other vital and safety critical radio communications such as Air Traffic Control.

When elected David Cameron suggested that his government would wasteful and inept quangos? Ofcom unfit for purpose?


Here is more of the Freeview DTT Interference story:

Freeview Interference from 2013

Up to 760,000 homes in the UK may find that they start to experience interference to Freeview Digital Terrestrial Television from 2013, according to a report from OfCom. As you're probably aware, the UK Digital Switchover is set to be complete by the end of 2012. Once this has been done, a part of the spectrum that was once used by analogue TV, will be auctioned off to mobile operators to use for the next generation of mobile Internet services, known as 4G 100mbps services, and is set to use the part of the band from 791 to 862MHz, otherwise known as UHF channels 61 to 68.

The problem, is that many TV aerials do a good job of picking up signals in that band, and if those signals are amplified by a signal booster, the interference from 4G base stations could overload the tuners in Freeview TV sets and set-top boxes. Particularly as risk from interference from 4G would be those that get their Freeview via a communal TV aerial (which are normally amplified), or those using a masthead TV amplifier, where the signal is amplified at the aerial.

In many cases, this 4G interference can be reduced or removed by using a filter, which would cost around £10. Ofcom is proposing that the 4G operators foot the bill for the filters. Filters will not be the answer for everyone though, especially those who rely on a Freeview signal that's right at the top of the band. Around 30,000 homes could be in this position, and the answer for them, would be to switch to a satellite TV service such as Freesat or Sky, or go for cable TV from Virgin.
More details: http://www.radioandtelly.co.uk/news/2011/06/freeview-interference-forcecast-from-2013.html


For more information please see:  Let's Be Clear  -  https://at800.tv/


March 2012 News:

THE GREAT 700 MHz QUESTION

Ofcom Announce:  "A resolution was passed signalling that the neighbouring 700 MHz band will now be allocated for mobile services [data, telephone, 4G etc] on a co-primary basis from 2015 throughout ITU Region One (Europe, Africa and the Middle East). This resolution makes it clear that there is now a realistic prospect for long term change of use at 700MHz." 8 March 2012

We know that the 800 MHz part of the television spectrum was to be sold off, probably to the mobile phone / data provider companies. But this ruling means that yet another chunk of spectrum, currently used by the domestic television broadcasting system, is to also be lost to the mobile phone / data industry.


THE GREAT 600 MHz QUESTION

Ofcom state:  "The 600 MHz band will be cleared of existing uses  [analogue television and current temporary digital, Freeview, television uses]  when digital switch-over (DSO) is concluded in a few months' time. It was our intention to award this cleared spectrum before the end of 2012. However, decisions taken at the World Radiocommunication Conference (WRC-12) in Geneva mean we think it sensible to reconsider our approach to the release of this spectrum." 8 March 2012

"Ofcom will shortly publish a consultation discussing how to secure long term value for citizens and consumers from the use of UHF bands IV and V, which include both the 700 MHz and 600 MHz bands. In particular, the consultation will consider whether - in light of the evolving international context and the expected growth in mobile broadband demand - enabling change of use at 700 MHz in the long term could increase the overall benefits delivered to citizens and consumers. This will include a discussion of the long term role that 600 MHz could play in delivering these benefits, and the implications of these longer term prospects on use of the 600 MHz band in the interim."

"It is clear that In these changed circumstances, it would be unwise to proceed with an award of the 600 MHz band before the implications of the WRC-12 decision for UHF spectrum as a whole are fully considered. For this reason, we have decided to postpone putting forward detailed proposals on how to enable use of 600 MHz spectrum until the conclusion of our consultation on the future use of the UHF spectrum band IV and V."    8 March 2012

What this means is that after 'DSO' there would have been some spectrum space at 600MHz that Ofcom / the government could sell off to bring money into the Exchequer. The sell off may have brought about additional television multiplexes (MUX's) that could have benefited the television viewer with more channel, perhaps local television or maybe more HD channels. However the loss of the 700 MHz television spectrum to the mobile phone / data networks means that existing television channels currently located in the 700 MHz block that is to be sold to the mobile phone companies, will now have to be moved down to the 600 MHz area.

This not only means a lot more re-planning of the current Freeview transmitter network, but also more re-tunes and possible reception problems and expensive and inconvenient television aerial changes / upgrades for viewers who are currently experiencing no problems. It also means that the potential for better or more HD channels on terrestrial 'Freeview' television may be lost.

Of course all this potential for viewer confusion could play very nicely into the hands of the pay TV providers; they may not only get their hands on a chunk of spectrum that they can exploit, but may also find confused viewers being told that they now have to buy an expensive television packages in order to continue watching TV.


Is there a 'silent hand' at work here? We'll say it's for Africa (seems like a good cause) but what it will mean is eventually, slowly but surely, getting our hands on the lucrative television bands in Europe - forcing off Free To Air television stations, and thereby 'encouraging' unsuspecting (ignorant) viewers onto our very expensive satellite television or data network contracts. Cynical? Ofcom will ssurely wave it all through without noticing.

Ofcom - unfit for purpose?


MORE ABOUT AERIALS AND UHF CHANNEL GROUPINGS - Technical Stuff

When considering digital television the viewer must also consider the aerial.  Although DTT (Freeview etc) - even when being transmitted at full strength after Digital Switch Over (DSO) - will be transmitted at lower powers than traditional analogue TV (about 7dB less) digital television receivers only need signals of about 20 dB less than analogue sets to work properly.  HOWEVER with analogue, if your aerial is producing a weak signal the pictures on the viewer's TV will just be a bit weak - i.e. snowy, grainy, noisy.  NOT SO with digital television! - If the signal produced by the aerial is a bit too weak then the pictures will simply not appear on the screen at all and the viewer will end up with a black screen.  Once the signal threshold has been reached or exceeded then the perfect digital pictures will return - With digital it is an All Or Nothing situation - there is no snowy analogue 'half way house'!

An aerial that is in good condition, not too old and damaged by the crows is essential, as is good quality (NO) VERY HIGH QUALITY screened digital,satellite grade 75 ohm coaxial downlead cable.  The aerial must also be of the correct GROUP for the digital signals (see below) and accurately installed and aligned with the appropriate transmitter.

When analogue 625 line colour television was introduced to the UHF band in the 1960's each transmitter site was allocated a group of four channels to transmit the four anticipated tv stations (BBC1, BBC2, ITV and The Fourth Channel).  The four UHF channel groupings were close together and repeatedly used at hundreds f sites all over the country to make efficient and organised use of the limited radio spectrum available.  Due to the laws of physics aerials can only work effectively over a limited range of frequencies (channels).  For this reason The UHF band, which covers a huge range of frequencies from the lowest at 471MHz (UHF Channel 21) to 847MHz (UHF channel 68), was split up into three "GROUPS" or "AERIAL GROUPS":

GROUP A aerials can work efficiently between u.h.f. channel 21 to u.h.f. channel 37 
GROUP B aerials can work efficiently between u.h.f. channel 35 to u.h.f. channel 53
GROUP C/D aerials can work efficiently between u.h.f. channel 48 to u.h.f. channel 68

If a grouped aerial is used to try to receive an 'out of group' transmission poor reception will usually result as there will be very little 'gain' and the direction properties of the aerial may also be lost - instead of the main pick up lobe facing directly in front of the aerial, as it should, the lobe will be distorted and face off at some unwanted angle.

More recently new aerial groups have been introduced that cover wider bands, the gain and directional characteristics may be slightly less than the above equivalents, but they are designed to work with larger groups of channels properly:

GROUP K - 21 to 48
GROUP E - 35 to 68
GROUP W - WIDEBAND - All Groups from 21 to 68 (The gain of these aerials may not be quite as high as those for the grouped aerials, A, B, C/D)

GROUP W Aerials have become much more frequently used with the introduction of DTT where wide spacings of u.h.f. channel groups are used at the transmitter.  It is not always necessary, however, to use a WIDEBAND aerial simply because one is trying to receive digital television, many transmitters have managed to squeeze in the DTT multiplexes in groupings that fall within the existing analogue grouping.

As an example, in the Sutton Coldfield transmission area five of the six digital multiplexes fall within the original analogue grouping, except the highest multiplex, MUX-D which is on u.h.f. channel 55, channel 55 just falls outside the GROUP B Aerial grouping!  Maybe a group B aerial would work okay, but maybe it would be better to install a Wideband aerial just in case?  But then the gain of a wideband aerial in the B group part of the spectrum may be a little lower than the gain of an equivalent B group aerial.  Difficult


Sutton Coldfield's channel groupings:

Analogue: BBC1 = ch 46   BBC2 = ch40  ITV = ch43  Channel Four = ch50 Five = ch37(Lichfield)    :  U.H.F channels 37, 40, 43, 46 and 50 fall within AERIAL GROUP B. 

The DTT multiplexes are MUX1= ch41  MUX2 = ch44  MUX-A = ch47  MUX-B = ch51 MUX-C = ch52   MUX-D = ch55


Winter Hill's channel groupings:

With Winter Hill it's much easier - all channel groupings fall within the C/D Aerial Group:

WINTER HILL Analogue TV : Channels BBC1= ch55   BBC2=ch62   ITV1=ch59   CH4=65   FIVE=48 (very low power)
Digital TV: MUX1=ch56  MUX2=ch66  MUXA=ch68(slightly lower power) MUXB=ch67  MUXC=ch60  MUXD=ch63



THE MOVE TO DIGITAL TERRESTRIAL

The FREEVIEW DTT service was established jointly by the BBC, Crown Castle International (the then transmission service provider) and SKY to bring Multi-Channel television reception to a wider audience and via the existing infrastructure of terrestrial television masts that could be received through standard rooftop aerials.

FREEVIEW digitally transmits multiple television services in blocks called "Multiplexes"* The BBC channels BBC1, 2, 3, 4, BBC News 24, CBBC, CBeebies and BBC Radio etc. are all transmitted together in the BBC's dedicated multiplexes; ITV1, ITV2, ITV3, ITV News etc are lumped together into another multiplex and other TV services such as Channel Four,  FIVE, Sky News etc arrive in further multiplexes.  Many more TV and radio channels are available by this method than would otherwise be possible by traditional analogue methods.  Further services, in addition to FREEVIEW, are also available via the normal rooftop television aerial and set top box as pay to view services providing a number of so called 'premium' channels. These channels are packaged into further multiplex space and require a viewing card, bought at additional cost, and a dedicated set top box that is equipped with the necessary viewing card slot - conditional access. These pay tv boxes will also receive the subscription free FREEVIEW services.

Many of the main terrestrial television transmitter sites, along with some of the larger relay transmitter sites, started carrying the digital Freeview services years in advance of analogue switch off and full DSO. However to squeeze in digital television alongside existing analogue television services meant that not all transmitter sites could be used to transmit digital TV due to the lack of spare channels / frequencies available in the UHF television band between channel 21 and 69. Another consequence of the limited number of UHF channels was the fact that Freeview (and the other Pay TV channels) had to be transmitted at significantly lower power than would be the case after Digital Switch Over was complete.

The vast majority of small relay transmitters (of which there are hundreds) could not initially carry Freeview and other stations (Pay TV etc) at all due to the severe lack of frequencies / channel space. This lack of spectrum space would hold up the expansion of DTT until all the analogue television transmitters were switched off - freeing up spectrum for the smaller relay transmitters to radiate digital TV signals.

Initially around 70 - 75 percent of the population could receive DTT but very much less of the geographical area of the UK would be covered by DTT signals.  This is because for both economic reasons and the need for radio spectrum efficiency, television signals must be concentrated on areas of significant population.  Even with the 99.6% population coverage of the analogue television network there would be vast geographical areas that could not receive any signals - but this is generally not a consideration if there are only one or two households in a sparsely populated area.  The later analogue TV relays to be commissioned at great expense only provided TV reception to populations of only one or two hundred households.  With the initial DTT network it was relatively easy to get coverage to densely populated areas with a just few dozen transmitters, but to bring coverage to the last 25 to 30 percent of the population requires many hundreds more transmitters to be built - incredibly expensive of course, and really demonstrating the Law Of Diminishing Returns!

When all the analogue transmitters (UHF PAL Colour) of BBC1, BBC2, ITV1, Channel Four and FIVE are switched off by 2013, digital terrestrial television will be able to be transmitted from all necessary low power relay transmitters (though not all of those previously needed by analogue television), and at full power from the main transmitter masts, to provide the 99+% coverage that was previously available via the old analogue TV networks.  The switching off of analogue television was, however, a politically a hot potato because millions of people could have been left without any television, perhaps unwilling to pay for a new set top box and  a possible aerial upgrade or adjustment.


*NOTE:  A MULTIPLEX is a special method of digital broadcasting in which the a single transmission can be used to combine and transmit several television services.  The use of sophisticated digital compression techniques, such as MPEG4, enables many television and radio services to be accommodated (squashed into) a single multiplex.  Several multiplexes will be used from each television transmitter to bring a multitude of channels to the viewer/listener.  A multiplex is broadcast on a single UHF channel just like an analogue TV station, but using digital technology.  This digital technology uses very clever compression techniques to shoe-horn in five or more television services into the space normally occupied by a single analogue station.



"FREESAT" - Subscription Free Satellite Television

As an alternative to FREEVIEW via an aerial,  free digital television channels are available via the FREESAT service which has been launched, independently of Sky TV, by the BBC and ITV.  FREESAT is free to air unlike Sky Television - this means that there is no monthly subscription millstone. All that is required is a small set-top box that costs about £50.00 and a mini-dish (satellite aerial).  There may already be a minidish fitted to the residence from former residents or a lapsed Sky Television installation. As long as the minidish and LNB are in working order this can be connected directly to a new "Freesat" set top box for instant subscription free satellite television.

[Other methods of receiving digital television are via SKY and paid subscription to the SKY satellite service, or paid for monthly subscription to a local cable company, if there is one. Additionally Sky also offer their version of a free satellite service.]


LINKS TO OTHER HELPFUL WEBSITES:
(All links will open in a new window)

www.aerialsandtv.com  -  Aerial installations, theory and practice

www.atvcircuitsandservicemanuals.co.uk  -  TV service information

http://www.wrightsaerials.tv/  -  Bill Wright's aerial installers website

FREESAT official website - http://www.freesat.co.uk

Goodmans Digital UK - Manufacturer of FREESAT Set Top Boxes


WHY THIS PAGE?

It was a Reader's question that prompted me to include this page on the website back in 2005:

Peter W Robinson asked:  "I live in a valley.  Please can you tell me when we will have a transmitter able to transmit Digital TV to our homes - other than BBC which is very good.  Of course we could get a dish for sky etc. but I believe that sooner or later we should be able to receive the Freeview signals from ITV and other channels.  Please let me know what is holding up this work?"

In essence the answer to the question is this:

How Analogue Television Was Arranged

The five 'ordinary' analogue television channels, BBC1, BBC2, ITV1, Channel Four (or S4C) and FIVE are broadcast on the UHF band (Ultra High Frequency radio band) using the analogue PAL (Phase Alternate Line) colour standard in the UK on frequencies between 471 MHz and 847 MHz which are divided into 'channels' numbered from 21 to 69.   There have been over 900 television transmitter masts constructed jointly by the BBC and IBA between the 1950's and 1990's (and latterly some further small relay masts installed by Crown Castle and NTL).   Almost all of these transmitting stations transmit the four terrestrial TV stations; BBC1, BBC2, ITV1 and Channel Four/S4C.  Each TV service having being carefully allocated a specific 'UHF Channel' number to be transmitted on from the mast.  Eg the Winter Hill mast in Lancashire transmits on these channels:

BBC1 on UHF channel 55
BBC2 on UHF channel 62
ITV1 on UHF channel 59
Channel Four on UHF channel 65

Some 50 of these masts are designated as 'Main Stations' and transmit at high or very high powers in the order of 20,000 to 1,000,000 Watts effective radiated power.  These 'main stations' reach the majority of the UK population.  The remaining population has to be served from hundreds of medium or low power relay transmitters using powers typically in the order of between 2 Watts to 10,000 Watts.  In this way 99.6% of the population of the UK is served with four channels of analogue TV.

Due to the fact that the UHF television band was originally planned in the 1960's to accommodate four television services it was a challenge for the DTI, ITC , NTL and BBC to factor in a fifth television service in the early - mid 1990's in the form of Channel Five Television.  Because of the limits of radio spectrum space available FIVE TV, as it is now known, could  be allocated a total of (only) 47 transmitters and so reaches around 80% of the UK population.  Some of Five's transmitters are at the same or similar power as the other four analogue channels, but there are many that are at lower power; for example FIVE TV is transmitted from Winter Hill on UHF Channel  48, but at much lower power than the other four TV services so as not to cause interference to existing transmitters elsewhere.  This is also the case at other FIVE TV transmitters where lower power must be used to avoid interference to viewers of other stations.  Powers for FIVE's analogue transmitters ranged from 33 Watts to 1,000,000 Watts of effective radiated power.


What UHF Channels Will Be Used For D.T.T. Post Digital Switch Over?

It will be all change post digital switch over, not only will there be no more analogue television, but there will be a new arrangement for the allocation of UHF channels used in the UK for broadcasting. Not all of the channels previously used for analogue (PAL) television will be used for digital broadcasting. The unused channels will probably be auctioned off by the government / Ofcom to raise money for the treasury.

These auctioned off channels may go to the highest bidder and may or may not be used for transmitting television. There is a possibility that the auctioned off channels could be sold to other commercial TV operators, possibly used for high definition (HD) television services, or may be used for something entirely different such as data communication.

Our friend and correspondent, Martin Watkins, has complied one of his typically marvellous transmitter lists which you can download here - the list (v9) was compiled in November 2006 and shows the ITU UK DTT allocations that were anticipated at that time, however things have been continually changing since then so this list is now out of date (November 2009) but we have left it in place here merely out of historical reference.

Pre Digital Switch Over Coverage
                of digital terrestrial television - Five TV





OFCOM : SNOUTS IN THE TROUGH

The 'Independent' media regulator costs taxpayer millions and holds Middle England in contempt.


[ Firstly - the staff and engineers of Ofcom are, without any doubt, excellent people who are unquestionably helpful and professional. The problem with Ofcom is not their excellent staff, it's the structure and remit of the organization created by Government and its Chief Executive. Ofcom's primary function, it appears, is to maximise the amount of money made for the Exchequer, rather than to instill technical excellence. ]

Talk to anyone in the insular, self-regarding, oh-so-liberal London media world about Ofcom chief executive Ed Richards and they will say he’s brainy, self-assured and carries a vast amount of information around in his head. True, he is slick, articulate and plausible, dressed in dark, well-cut suits with fashionable narrow lapels. But more than anything, Ed Richards is a leading member of the New Labour political establishment, an interconnected, back-scratching mafia that, while bankrupting Britain, made its own members seriously rich.

For Richards has done extremely well for himself — the total amount of his salary and pension benefits since he took the helm of Ofcom in 2006 is heading towards the £2 million mark. When asked to justify his own captain-of-industry salary or his watchdog’s  £115 million budget, he does not talk of anything so vulgar as ‘value for taxpayers’ money’. Rather, he speaks of ‘delivering objectives for the least possible resource’.

And, in typical bureaucrat’s gobbledegook, he once told a committee of MPs that budget forward planning is a matter of setting ‘multi-year horizons’. As well as being a master of New Labour management lingo, Ed Richards has impeccable connections. Greg Dyke, the BBC director-general brought down after his run-in with the Blair government over Iraq weapons expert David Kelly, described Richards as ‘a jumped-up Millbank oik’.

But that is to grossly underestimate his smooth political skills. Perhaps his greatest political achievement has been to persuade David Cameron to break yet another of his pre-election pledges. As part of his promised ‘Bonfire of the Quangos’, Cameron vowed that under a Conservative government the vast, politically correct Ofcom empire would ‘cease to exist as we know it’.

Today, the truth is that this citadel of New Labour remains, under a Tory- dominated Government, utterly unreformed. If David Cameron thinks Ofcom is going to show respect for the family values he espouses or do something about properly policing the 9pm watershed, he is deluding himself. As one industry insider puts it: ‘Ed Richards cannot understand public anger about a row over decency because he views the world entirely through a Left-wing prism. He simply doesn’t get what all the fuss is about.’

Richards is protective about his personal privacy, and Ofcom declines to provide any details about his life or career beyond the barest details. Edward Charles Richards is 45, a graduate of the London School of Economics, and lives in South-West London. He seems to share Ed Miliband’s ambivalence towards marriage, for though he has two children with his long-standing partner Delyth Evans, he has not married her.

Evans, seven years older than Richards, is a well-connected member of the media-political establishment in her own right as a communications consultant. She was a speechwriter for Labour leader John Smith and a Labour member of the Welsh Assembly from 2000 to 2003.
Her business of consulting on media policy must be greatly assisted, one assumes, by sharing a roof with the most important media regulator in the land.

'Ed Richards is a jumped-up Millbank oik'  But how has a man who has never held an executive position in the real world risen so quickly to a job with a salary of £381,713 (though it was revealed recently that he had taken a 10 per cent cut)?

The answer, it turns out, is all down to football.

During the late Nineties, a group of young Labour activists and Labour-supporting media people had kickabouts on a pitch in a scrubby area of North London near King’s Cross railway station. They named their team Demon Eyes, an ironic homage to the Tories’ depiction of Tony Blair as satan in their 1997 general election posters.
It was through Demon Eyes that Richards got to know future Labour Cabinet ministers Andy Burnham, James Purnell, David Miliband and Ed Balls, the last-named an aggressive centre-forward who frequently shouted abuse at the referee as well as his team-mates.

So connections, rather than executive performance, explain Richards’s rise. Indeed, his curriculum vitae is strikingly thin. In the late Eighties, he worked briefly as a researcher for a TV company that made programmes for Channel 4, which may explain his apparent profound reluctance today to criticise any of the broadcaster’s output. For a brief time he was political  adviser to the then National Communications Union, before working for two years for Gordon Brown in the early Nineties.

Former Ofcom chief executive Stephen Carter left in 2005, allowing Ed Richards to get the top job

He later joined the BBC in the key corporate role of Controller of Corporate Strategy, before being chosen by Tony Blair in 1999 as senior adviser for media, telecoms, internet  and e-government. He worked on the 2001 Labour election manifesto and together with two key Blair loyalists (and Demon Eyes team-mates), Andy Burnham and James Purnell, Richards drafted the Communications Act that set up Ofcom. He proceeded to rise yearly up the ranks of the Guardian newspaper’s list of media movers and shakers, reaching number eight, and  was described by the paper as a ‘quintessential New Labour man’.

Richards moved from Downing Street to the number two role at Ofcom. When the watchdog’s chief executive Stephen Carter left in 2005, Richards got the top job.
The fact that few objected to the blatantly politically partisan Richards’s appointment to head what was meant to be a totally independent regulator speaks volumes for the moral ambiguity of the New Labour years.

Incidentally, to further demonstrate the incestuous relationship between No 10 and that same supposedly independent media regulator, Carter later went back to Downing Street in a doomed attempt to rejuvenate Gordon Brown’s media profile. Previously, Carter had been a senior executive at NTL, the cable TV company that went bankrupt with debts of £12 billion.

According to an allegation contained in court documents at the time, he told a fellow executive who feared he had misled shareholders: ‘What I tell them is nine-tenths bull**** and one-tenth selected facts.’ Soon after these alleged remarks, the firm collapsed in one of the largest corporate bankruptcies in U.S. history.

He defends the media industry, not the public. No one suggested he was responsible for the state of NTL’s finances, but U.S. court documents filed by aggrieved investors accused him and three other directors of ‘deceit’ and making ‘materially false and misleading statements’ to the media about the company’s true financial status. Carter — who denied the allegations — walked off with £1.7 million in compensation, including a £600,000 bonus. The other key figure at Ofcom is Colette Bowe. She became non-executive chairman in March 2009, replacing Lord Currie, who also happened to be a Labour donor and adviser and was ennobled by Labour as Baron Currie of Marylebone.

Bowe is a career economist, a former board member of the Left-leaning think-tank the National Institute of Economic and Social Research and a board member of the Camden People’s Theatre. She earns £180,000 a year — for working ‘up to three days a week’ for Ofcom. Her pay triggered criticism from MPs, who asked why a part-time employee should earn more than the prime minister. Bowe (whose appointment was championed by Labour’s Peter Mandelson) recently agreed to a 10 per cent pay cut, like Ed Richards.

She also holds several other lucrative posts, saying she’s ‘well able to give 60 per cent of my time to Ofcom’. She had previously been head of the investors’ watchdog, the Personal Investment Authority, where she was criticised in 1998 for slow progress in clearing up a £15 billion pension mis-selling scandal. She  left with a pay-and-compensation package of nearly £500,000.

As for the rest of Ofcom’s executive, the majority of members are on six-figure salaries. Latest figures show that Jill Ainscough, the chief operating officer, received an annual package worth £261,858, including pensions, benefits and £25,000 performance pay; and Stuart McIntosh, head of the Competition Policy Group,  took home £282,139 in pay, pensions and benefits. Polly Weitzman, head of Ofcom’s Legal Group, enjoyed a package worth £250,971; and Christopher Woolard, head of Content, International and Regulatory Development, got £214,125 in pay, pension and benefits.

Six individuals were listed as earning between £150,000 and £164,999, including the grandly titled Director of Spectrum Policy (Olympics), whose job it is to ensure there are adequate wireless communication channels for international broadcasters at the 2012 Games. The perks aren’t bad either. Over the past five years, individual expenses bills have included up to £5,278 for overseas accommodation and up to £13,766 a year on air fares.

One executive — former Left-wing newspaper editor Ian Hargreaves, who was Ofcom’s international director — claimed £22,726 for travel costs during the year 2007/8 while on a total pay package of £247,896. In 2008/09, seven members of the executive board put in expenses totalling £58,388. The previous year, they claimed £63,754. 
So incestuous is the world of think-tanks, government and media policy that Professor Philip Schlesinger of Glasgow University has written an academic paper on the subject, tracing how ‘a New Labour policy generation has emerged’. This was enshrined in the thinking that went into the legislation that set up Ofcom — through a government Bill drafted by Ed Richards.

Under Richards and New Labour, criticism of anyone working in their beloved ‘creative industries’ was tantamount to sabotaging the very branding and performance of UK plc. With this mindset, it would be unsurprising if Richards saw his role as defending the industry — rather than the viewer. For example, after 4,500 complaints about the lewd final of The X Factor last Christmas, when Rihanna and Christina Aguilera appeared in soft porn performances on prime-time Saturday evening TV, Ofcom cleared the programme of wrongdoing, saying merely that the scenes were ‘at the limit’ of acceptability for broadcast before 9pm for a family audience.

This didn’t stop the recent review on the sexualising of the young singling out the offending X Factor show for special criticism. One media executive explained: ‘It is not a question of Ed Richards being out of step with middle England values — he would see it as an insult if you suggested he was in step with them.’

So there was no surprise that when Ofcom censured Channel 4 — albeit in a rather mealy-mouthed way — after Glaswegian comedian Frankie Boyle made unrepeatable ‘jokes’ about Katie Price’s disabled son, it failed to fine the channel. Richards himself is, according to one media executive, a grey, technocratic figure, and Ofcom’s fashionably appointed £90 million HQ on the Thames is a dreary place in its boss’s own image.

Technically, Ofcom is a non- ministerial department, but is subject to parliamentary scrutiny, which means Richards must present himself before the Public Accounts Committee. Perhaps he got complacent during the loose-touch years of New Labour, but when he went before the committee last December he took quite a bashing.
According to someone who witnessed the encounter, it was ‘a train wreck’ as he stammered and obfuscated, unable to explain how his empire spent millions and millions of public money.

Steve Barclay, the Conservative MP for North East Cambridgeshire, a former soldier who worked in the private sector until winning his seat last year, was scathing about the state of Ofcom’s accounts.  In effect, it was accused of burying millions of pounds of unspent money in various ‘contingency funds’, while rewarding its own staff. In one year, £14 million (10 per cent of the total budget) was used to top up the staff pension fund. Until the wind changed with a new government and the need for austerity measures, with lavish public sector salaries coming under scrutiny, Richards even employed an assistant, grandly styled as Director of the Chief Executive’s Office, on a salary of £213,000.

‘Ofcom has spent £2.7 million on something called ‘‘thought leadership’’ and they employ 180 consulting providers,’ says Mr Barclay. ‘So you can imagine who’s scratching whose back. The accounts would certainly not pass muster in the private sector.’ Richards, one observer concedes, was quick to realise after such criticism that bodies such as Ofcom needed at least to make a gesture of tightening their belts. He froze executives’ vast salaries.

Though he is known to respond furiously to any criticism, he reluctantly bent to pressure to reduce the size of Ofcom, which had increased its staff numbers every year of his tenure. Whole aspects of the empire, notably its media literacy unit, which produced reports such as one that found children were often better on the internet than their parents, have been pruned, and the number of staff reduced by 153  in the past 12 months to the still bountiful level of 720.

But many Tory MPs remain frustrated at the way the media remains in the firm grip of Ofcom, which continues to function according to Blairite-Brownite nostrums, despite the fact Britain has a Conservative-dominated government. It’s rather like an incoming Labour government finding an important department being run by alumni of the Bullingdon dining club and opting to keep them all in position.Indeed, there are signs that Jeremy Hunt, the lambada-dancing Culture Secretary who is not entirely trusted by the Tory Right, is as comfortable with Richards as were his Labour predecessors.

Meanwhile, the lesson gleaned from Ed Richards’s survival from Labour to Coalition rule is that we shouldn’t expect any tougher control of the more distasteful programmes screened by our main TV broadcasters.

That, and the fact that once New Labour snouts are in the trough, it’s very difficult to get them out.


Read more: http://www.dailymail.co.uk/news/article-2007124/Snouts-trough-Independent-media-regulator-costs-taxpayer-millions-holds-Middle-England-contempt.html

Should Ofcom be abolished immediately?


Why Ofcom is not fit for purpose
The PLT issue


The following is from The EMC Journal, issue 85, November 2009
Log in to the EMC Information Centre to download the journals and full articles:
http://www.theemcjournal.com
http://www.compliance-club.com

Text in blue are quotations from the OFCOM document 2.9.2009.

Ofcom’s  PLT  statement of  2nd  September this  year (www.ofcom.org.uk/radiocomms/ifi/enforcement/plt/) is a prime example of why it is not fit for purpose as a spectrum regulator and protector. Almost every line contains things that are economical with the truth, irrelevant, or spin – that is, when they are not blatant misdirection, or just plain insulting. Let’s look at a few quotes from it....

“Ofcom has exercised its enforcement functions under the EMC Regulations. Ofcom has investigated alleged breaches  of  the  EMC  regulations  resulting  from  the supply of Comtrend PLT apparatus by BT...... On the evidence,  Ofcom  has  not  so  far  found  that  there  is  a
breach of the EMC essential requirements. Ofcom has therefore  decided  against  taking  further  enforcement action at this time”

But what “evidence” are they talking about? Of the technical evidence submitted in formal complaints by the UKQRM group (www.ukqrm.org)  and  by  the RSGB,  Ofcom  has  refused  to respond to any of it.

By  all  accounts  Ofcom  has  undertaken  no  technical  tests  or examined  the  Comtrend  PLT  devices  (the  ones  that  are  the subject  of  all  Ofcom’s  complaints  of  interference  from  PLT devices) against the points made in these complaints.

The  RSGB’s  complaint  (published  on  their  website, www.rsgb.org) was made on 31 July, just four weeks before Ofcom’s PLT statement. That’s hardly sufficient time for them to consider the evidence in detail and then write their response, if they could actually have been bothered to do so. Which they weren’t.

Indeed, their response does not even mention the two central points of RSGB’s complaint:

a)  Comtrend’s PLT products emit conducted noise at levels way above the limits in EN55022, the most relevant EMC product standard

b)  They rely for their EMC Declaration of Conformity on a discredited CISPR committee draft (CISPR/I/89) – simply a committee paper – never a published standard – which anyway was withdrawn several years ago.

Either of these plain and obvious facts should be enough to have their products immediately withdrawn from the entire EU market. That Ofcom have not done so brings the whole process of Single Market Compliance and CE marking into disrepute.

“Over  the  past  12  months  Ofcom  has  received  143 individual PLT interference complaints; all from radio enthusiasts... There are many other users of the HF Band including  long  range  aeronautical  and  oceanic communications,  the  Ministry  of  Defence  and international  broadcasters.  Ofcom  has  not  received complaints of interference to these services.”

Ofcom are apparently suggesting that complaints from radio enthusiasts are not as important as those from professional radio users. Would Ofcom have acted differently if there had been complaints  from  the  professionals? The  EMC  Directive  and the  UK’s  corresponding  2006  EMC  Regulations  do  not discriminate  in  this  way,  and  in  fact  the  EMC  Directive’s Recitals make it clear that Member States must actually protect amateur radio from “electromagnetic disturbance”.

Although professional radio users may not have complained of interference from PLT yet, you can be sure that they have been telling Ofcom how worried they are that it may happen!

As for being economical with the truth, Ofcom’s statement just happens not to mention that  the total number of complaints they have received about PLT interference, in just over a year, is  already their 4th  highest after complaints  about  lighting equipment; thermostats and aerial pre-amps which have been accumulating for several years.

Their statement also just happens not to mention that the rate at which they are receiving complaints of interference from PLT is far higher, per million units sold, than from any other technology.

“Evaluating the complaints received and the evidence so far obtained, Ofcom has concluded that there does not at present appear to be significant public harm arising from this situation.”

Perhaps Ofcom could point to the place in the 2006  EMC Regulations where it says that the number of interference complaints are a factor in determining whether something meets the Essential Requirements or not?  And perhaps they could also point to the place where it says that professional radio
users are more important than mere enthusiasts?

And where does the test of  “significant public harm” arise in the  EMC  Regulations?  None of these issues exist  anywhere other than in the fevered brains of Ofcom’s spin-doctors, who hope to convey the impression that they have some meaning – some relevance to the issue of interference from PLT, which of course they do not.

Ofcom  has  managed  to  get  BT  to  sort  out  many  of  the  143 reported problems with Comtrend PLT products. (BT sell the Comtrend devices bundled with their “BT Vision” product, so that customers don’t have to trail Ethernet cables from room to room, causing unsightly lumps in the carpets).

But the point is that the interference complaints are caused by the fact that these PLT products have a non-EMC-compliant design. If the PLT devices were compliant in the first place, they would most likely not have caused any interference.

“It is recognised that EMC compliant equipment may still, in certain circumstances, have the capacity to cause interference to other radio communications equipment. This  may  happen  due  to  the  manner  in  which  it  is installed or operated.”

Well, yes, but this is irrelevant. This is not a situation where a compliant  device  happens  to  cause  interference  to  a  radio receiver. Comtrend PLT devices are designed in such a way that they are almost certain to cause interference when operated in the vicinity of an HF (short-wave) receiver.

And as to “the manner in which they are installed” – how is this even possible? All you do is plug them in – how wrong can you get that?

“Is  there  an  EU  harmonised  standard  for  PLT?   No. The EU has not yet published a suitable harmonised standard for this type of apparatus.”

There is no standard specifically  for  PLT, but PLT is quite clearly  already  covered  by  EN  55022  –  whose  conducted emissions limits the Comtrend devices exceed by about 30dB.

And as for creating “a suitable harmonised standard for this type  of  apparatus”  –  it  seems  that  this  may  prove to be impossible (see later).

“Are  existing  EU  harmonised  standards  for  other products helpful?  Existing  harmonised  standards  are  helpful  only  to  a limited extent because they are not specifically intended for this type of equipment.”

Well, the information technology (IT) EMC standard, EN55022, does cover PLT (as mentioned above), because PLT devices are simply another kind of IT device. But what the PLT industry lobby wants is a standard that says that simply because a product is PLT, it is permitted to emit 1,000 times more radio-frequency noise  into  the  mains  network  than  anything  else  is  legally allowed to emit.

If  such  a  standard  was  created,  you  can  be  sure  that  other powerful industry lobbies would very quickly insist on having their own EMC standards that allowed them to emit 30dB more noise into the mains distribution too.

After all, if PLT products can emit noise at this high level and yet enjoy a presumption of conformity to the EMC Directive, why not their products?  Then they could remove all their mains filters and save a very great deal of money.

“Ofcom believes the electromagnetic disturbance produced by this technology is an inevitable by-product of  its  operation and not  attributed to poor design or manufacturing.”

This is a perfectly correct statement!   Only not in the way that Ofcom wants it to appear to the reader. The Comtrend PLT design is not at all “poor” and neither is
their manufacturing. Both are perfectly competently done. It is just that the design of Comtrend’s PLT products is intended to put signals onto the mains distribution network at 1,000 times the maximum level required to protect the radio spectrum from interference. So of course “the electromagnetic disturbance produced by this technology is an inevitable by-product of its operation”!

Aren’t Ofcom’s spinmeisters clever? One has to be impressed!

But since Ofcom are employing such clever people, why doesn’t it employ them to do something a little more useful, perhaps something that contributes to Ofcom’s legal duty of protecting the radio spectrum?

For example, they might apply their huge and powerful brains to noticing that Comtrend’s EMC Declarations of Conformity are complete eyewash.

“Would the development of an EU standard for PLT help?  Yes. At  present,  testing  and  assessment  takes  place against a backdrop of wider technical uncertainty than is normally the case and there is an increase in the take-up of this apparatus across Europe. The  development  of  such  a  standard  would  be  an
important  step.  The  standard  could  be  used  by manufacturers  and  Notified  Bodies  to  assess performance against recognised benchmarked values. If the apparatus complied with the harmonised standard under  the  Regulations,  there  would  be  a  legal presumption  that  the  apparatus  met  the  essential requirements.”

There is work ongoing in CISPR/I to try to create a product specific  standard  for  PLT  devices,  but  it  suffers  from  huge difficulties because the opposing factions (PLT manufacturers versus almost everyone else) are each determined to get their own way, and there is no middle ground.

Either  PLT  emits  at  1000  times  the  emissions  limits,  or  it complies with those limits and doesn’t work. (At  least,  this  is  the  entrenched  position  taken  by  the  PLT industry, although recent work has shown they can emit at the limits given in EN 55022 (the “CISPR limits”) and still achieve data rates that would satisfy the vast majority of their market. But the PLT Industry appears to believe that because it spends so much on lobbying, it should be able to get just exactly what it  wants.  Unfortunately,  because  the  way  the  European Commission operates, this is quite a reasonable belief.)

Anyway, an “EU standard for PLT” is a complete non sequitur. There is no need for any product to declare compliance to any standard. A technical assessment for EMC compliance purposes can use Harmonised Standards, or not, as the manufacturer sees fit. So why all this fuss about standards?

Ofcom  states  that  it  believes  that  the  electromagnetic disturbance is an inevitable by-product of the operation of PLT devices – which is actually an admission of non-compliance! Since  they  don’t  appear  to  understand  this  basic  point,  we suggest  Ofcom  bothers  to  actually  read  the  Essential Requirements in the UK’s EMC Regulations – where they will see  that  apparatus  is  simply  not  permitted  to  be  designed/constructed in a way that interferes with other equipment, and especially not with radio reception.

The fact is – as many have said – broadband PLT (“Greedy PLT” as it is coming to be known) such the Comtrend products, uses an inappropriate technology. It deliberately produces a lot of  electromagnetic  energy,  then  tries  to  couple  it  into  an unknown impedance of unbalanced, unscreened cables (i.e. the mains distribution  network  in  a  house). Any  radio  engineer would call that a recipe for disaster. And it is.

This is why there is all this fuss about creating an “EU standard for  PLT”.  Such  a  standard  would  effectively  authorise  the Greedy PLT industry to claim presumption of conformity and legally affix the CE marking to their horribly noisy (by design) products, even though they could not possibly comply with the Essential Requirements.

A final piece of nonsense and [Ofcom] obfuscation:

“The  EU  Commission  is  aware  of  concerns  resulting from the proliferation of PLT in the EU and in response, issued a mandate (M/313) to the European Committee for  Electrotechnical  Standardisation  (CENELEC)  to produce a PLT harmonised standard”

M313 is totally irrelevant to the compliance of PLT devices. In fact, it specifically excludes them.  Instead, M313 concerns the compliance of complete data networks.

Spin,  once  again.  Or  is  it  obfuscation?  Whatever, it is intentionally misleading. It is also offensive and/or insulting, because it assumes that readers are so ignorant that they can’t tell the difference between a network and a device that connects to it.

M313 has been worked on for 10 years with no signs of success. There has been some further work on it recently, but agreement looks as far off as ever, and even  then  many  commentators suggest that it could never be applied to PLT networks, simply because – by their very nature – most mains networks pre-date the EMC Directive and were never installed for the purpose of carrying data in the first place.

Should we be surprised by all the spin, smokescreening, whitewash, eyewash, hogwash and (no doubt) many other kinds of wash, in Ofcom’s PLT statement of the 2 nd  September 2009?

Well,  probably  not,  because  Ofcom  is  manifestly  unfit  for purpose.  We  should  probably expect that  –  given  its contradictory  roles  –  something had  to  give,  and  the  PLT statement is just a result of that failure to reconcile opposites.

Ofcom was conceived and created to fill the role of a single regulator to oversee the apparently converging fields of broadcasting, telecomms and spectrum protection. As far as spectrum protection is concerned, Ofcom is required to be both poacher and gamekeeper. What has happened is that the needs of telecoms and broadband (the spectrum poaching role) have prevailed over  proper  management of  the spectrum  (the gamekeeper role).


Someone who has long worked in Government in the UK, and who  shall  remain  nameless  (for  obvious  reasons),  wrote  the following in a private email recently:

“Having worked in Ofcom I know how that works too. Created by the present Government, it is rather like an out-of-control  child  that  sometimes  attacks  its  own parents  and  ignores  anything  it  doesn’t  like.  It  is dominated by media luvvies and telecoms economists, with spectrum management coming a poor last (just one fact, out of many: they have reduced EMC enforcement / interference  staff  by  60%  since  taking  that  duty  over from the Radiocommunications Agency). And it has its  own  effective  spin  machine  that  –  like  the  whole organisation – is not accountable to anyone, which is not surprising when you realise that both of its Chief Executives have been No.10 spin-doctors themselves!”

The  only  real,  sustainable,  sensible  answer  is  to  remove  all EMC regulatory duties from Ofcom and give them to a separate, independent Regulator, who is able to focus on managing the radio  spectrum  without  being  dominated  by  big  business interests.

The above is from The EMC Journal, issue 85, November 2009, ISSN 1748-9253
Log in to the EMC Information Centre to download the journals and full articles:

http://www.compliance-club.com
http://www.theemcjournal.com


Detailed Technical Studies and Evidence from the ELECTROMAGNETIC COMPATIBILITY CENTRE

Read the article "Greedy PLT" here:
   http://www.compliance-club.com/PLT/PLT%20book.pdf


EMCIA Electromagnetic Compatibility Industry Association - http://www.emcia.org



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