All posts by Trevor Harris
Below are all of Trevor Harris's postings, with the most recent are at the bottom of the page.
@Watlingfen
DRM is designed for LW, MW and SW and can give quite good quality if there is sufficient bitrate. In fact several broadcasters are using this including BBC Worldwide. It seems that India and Brazil are the biggest users as large areas can be covered at very low cost. With 18khz bandwidth 64kb/s can be achieved. AAC_HE will produce higher quality than DAB at 128kb/s but not HiFi. This is what makes DAB look so silly. UK coverage only needs a few transmitters and so the costs are minimal.
@Brian Wright
The reason the BBC have to record the "proms" at the highest quality is that they want to sell CDs and DVDs. They also want to sell to other broadcasters who would not accept the low quality they dish out to licence payers.
The same argument applies to HD television which the BBC transmits to UK viewers at the lowest possibe bitrates.
@Mark
The £1 million was based on the actual cost of a 64kb/s station 2 years ago.
The £1 billion was not my estimate but considers DAB has been going for 18 years I think it is a reasonable estimate. The BBC has been agressively promoting Pure radios something they are not supposed to do. It is very noticable that in many of thier programs they promote DAB in there dramas. You often see DAB radios in the most unusual places.
I explained in my previous post why DAB is not FREE.
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@mark
mark said "The analogue TV pictures were superior to the compressed SD pictures on Freeview."
This is not quite true. Freeview pictures suffer from the low bitrates which have resulted from squeezing too many channels on each multiplex. PAL analogue pictures had very low chrominance bandwidth which means that the colour definition was very poor. It also suffered from a dot pattern appearing in strong colour areas. Analogue also sufferers from colour interference patterns with pictures containing things like fine striped shirts etc. In freeview the colour definition is only about a quarter that of the luminance signal. This is less noticable because the eye colour in less definition than black and white. On satellite I would say that SD pictures are generaly better than analogue.
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It does not seem clear to me how much Freesat will benifit. Freesat does not have any transponders of its own. The footprint of this satellite looks to be quite big which makes it less attractive to UK free to air broadcasters.
One possible use will be for Ultra high definition TV. Sky has been building up a library of 4K material for some time. Sky have also been experimenting with thier infrastructure and have found it possibe to pass 4k pictures across 4 HD links. Sky has made no commitment yet but I suspect they are very likely to do so in the next 2 years.
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The Ofcom report on Digital Radio is out
The latest annual report on digital radio from Ofcom shows people are still buying more FM radio sets than DAB, and 60% of new cars still dont have DAB as standard.
Forty-six per cent of people claimed ownership of a DAB digital radio, but out of those who do not have access to a set at home, only 14% claim that they are likely/very likely/certain to buy a set in the next 12 months.
Radio Today | Report: Not much interest in buying DAB
It is interesting to read the comments to the radio today article. Many seemed to be hacked off the switch off of regional DAB.
William Rogers, UKRD Chief says: This report tells us what we already know to be true. There will be no switchover to DAB in 2015, the choice of DAB as the alternative platform to FM for local radio was an error, DAB has failed to become the choice of platform for those listening to local radio stations, more sets are sold today without a DAB enabled receiver than those that have one, the choices people are making in terms of listening to a digital platform are increasingly those that are not DAB related and the coverage for local radio on DAB remains totally inadequate. This is an inferior and more costly platform.
So there we have it no switch off in 2015.
The end is near for DAB
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So what can the BBC do with DAB. Eventually DAB will have to be switched off. How and when is the difficult question. Most DAB recievers have FM and so can still be used. The big question is to whether or not we need to replace FM or just use the internet. One option is to switch to DAB+ but this is still not realy fit for purpose. At the moment I think the best radio system is DRM+ but it would be difficult to sell another system when DAB has been such a big failure. DRM+ can be introduced alongside FM and DAB which is probably the best solution. DAB and eventually FM could then be switched off when and if the listening figures on DAB or FM droped to a very small level e.g less than 10%.
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@mazbar
Only 20% well thats the point. This is a very low figure considering the DAB system has been running for 18 years!. Having a DAB radio does not mean people are listening on DAB. They all have an FM tuner. Most stations are available on FM and there are only a small number of DAB only stations as Ofcoms report shows. Many local stations are not on DAB. Many people bought DAB radios to listen to thier favourite station on a regional DAB mutiplex only to find they have closed down the regional multiplexes.
I would not choose a car on the basis of having a DAB radio. A DAB radio can always be retrofitted.
@Mark
Well I agree that the BBC might not be able to switch off DAB until an alternative is available. I do support DRM+ as it seems to me to be the best system at ther moment. DRM is a relative new standard but it is being used even by the BBC. In fact the BBC is activly involved in DRM and DRM+ development. What do you sugest then?
Actually I am 66 and active on the forums!
In general DAB and DAB+ are experiencing the low level of take up found in the UK.
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@PJH
Actually there is a DRM, DRM+ radio being sold on Amazon. The reason there are not many DRM sets available in the UK is because there are no DRM stations in the UK.
The BBC has been experimenting with DRM in the medium wave but with a very low bitrate. Using a bandwidth of 18khz would give much better results.
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@Mazbar
According to Ofcoms report only 15-19% of radios used at least weekly are digital. Oddly enough 45.7% of individuals claim to have a DAB radio in the home. So there are alot of people with DAB radios and don't use them.
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@Mark
The 23.9% is as you say for all listening. The 15-19% is the proportion of DAB radios used at least weekly. These are different numbers. Ofcoms report is available here
Ofcom | The Communications Market: Digital Radio Report 2013
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Saturday 21 September 2013 10:53AM
Actually Michael FM, AM and DAB are not 0p. The DAB system alone has cost hundreds of millions to set up. A single 64kb/s national station costs about £1 million a year to run. Some has estimated that the advertising campaigns have run into a value of a billion pounds. All paid for by licence payers. As Bevin said "If you want a free National Health Service you are going to have to pay for it".
The latest Rajar figures show DAB listening figures at 23.9% which makes DAB the most expensive white elephant ever.
There are few DRM radios at the moment but the chips are available to make them. There have been quite a few trials showing that coverage is comparable to FM so transmitters can be co-located with FM transmitters. FM and DRM can share band 2. It all means that DRM could be implemeted fairly quickly.
But I think we do need to consider that we may not need a seperate radio system if 3G and 4G prices fall.