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Freeview : Do I Need a New Aerial ?
The first question which most people ask is
"Can I get Digital reception with my present aerial ? "
Examination of the Digital Transmitters Nationwide page will tell you (amongst other things) of any change of group for your transmitter which is an essential starting point in order to answer the aforementioned question. After this it`s a matter of knowing the signal strength in your area to determine which aerial we would recommend. If your transmitter has a dedicated page on this site that is the first place you should look for the required information. The case of the Sheffield area (below) is a “worked example” of how to ascertain if you will need a new aerial or not.
As a “worked example” in the Sheffield area (not including those on the Chesterfield transmitter) if you got all five analogue programme channels perfectly then you would almost certainly have got Digital OK. This simple test proved that you are either on Emley Moor (which has not changed group) or you are on Sheffield/Crosspool ((or Belmont)) and you already have a wideband aerial potentially capable of receiving the digital broadcasts. If you are in the Sheffield area and only got a poor C5 the chances are you would have required your antenna changing.
One thing which needs to be stressed is the unreliability of the "Post Code Predictions
of Coverage". That is only a guide and it is frequently wrong. The very idea of being
able to accurately predict RF (Radio Frequency) coverage is laughable. How can they
possibly know if (for example) there is a tree or high building in the path from
any particular transmitter, or if the site is in an “RF dead spot” ? A site survey
by a decent aerial installer is far more accurate, but (unless that includes climbing
on the roof with an aerial and a Digi-
What is a Digital Aerial Installation ? The obvious (and correct ! ) answer is any aerial which receives a Digital signal well enough to allow reliable viewing. The word reliable cannot be over stressed because if your signal is marginal the Digital Cliff Edge can make viewing Digital a very frustrating experience, particularly when the sound mutes just at the punch line of a joke that`s taken 10 minutes to reach its denouement.......
Generally speaking a Digital TV aerial installation is one where the signal reception quality is maximised in order to minimise the effects of the Digital Cliff Edge. This may require a different group or quality of aerial, upgraded cable or wall plate, a better quality amplifier or splitter,
or nothing at all !
And, arguably, most people fall into the latter category.
Note that after Digital Switchover (DSO) many aerials which were not “digital” before,
will then be able to pick up the Freeview signal.
There are so many misconceptions and so much (deliberate ?) misinformation about "Digital" that we thought we should tell the unvarnished truth. We can do that because unlike the government (wanting to use the RF spectrum to make money, not that we should object to that ! ) or the TV retailers (wanting to sell you a new TV...) we have no hidden agenda. Perhaps the biggest Digital myth is that it will make your TV obsolete and that is a complete fiction. You may need a Set Top Box (from around £15) but all TVs will work with a Digital Box.
In fact, if you buy the correct box, even sets with no SCART input will operate perfectly well on Freeview. Furthermore, for ease of repair, we actually used to recommend buying an analogue TV (where available and use it with a Set Top Box.
The fact is that many unscrupulous people are trying to make money out of the Digital Switchover as the BBC have found, also see www.paras.org.uk.
I thought we would list the Positives and the Negatives of Digital.
So we can end on an upbeat note we`ll start with the Negatives.
1 What I said about inferior Digital picture quality is undoubtedly true, but that`s only if you have good analogue signals. Unfortunately, many people do not have good analogue signals because they either live in a "fringe" area or they have a poor quality aerial installation. If your signal is of sufficient quality to reliably drive a Digital box there are a lot of people who will get a greatly improved picture. Digital can be particularly effective at eliminating ghosting, provided the signal stay`s at the top of the "cliff edge", see graphic.
2 The sound quality is “near CD quality”. Better sound quality is always a positive but remember the analogue system has FM sound anyway, also see Nicam. If you are unhappy with the sound quality of your analogue TV it`s more likely to be deficiencies in the sets amp and speakers than anything else. If your set has a SCART (or Phono audio out) try putting the sound output through your stereo, though think of the neighbours if you`re tempted to turn it up !
If sound quality is important to you I would buy a Freeview box with separate Phono audio out sockets (though you can also use a SCART to Phono lead) which gives you the option to connect the STB to your Hi Fi. This is particularly useful if you want to listen to the radio stations which are also available on Freeview.
3 There are more programme channels available and the chances are you`ll like at least one of them. Most STB`s have basic "interactive" functions which could be really useful, for instance by giving you a choice of which sport at the Olympics you want to watch. Unfortunately at last Olympics the choices seemed to be Synchronised Team Pursuit Fencing or Rhythmic Freestyle Sandcastle Building rather than the swimming that I actually wanted. Consequently I was even more frustrated than I was before ! Let`s give it the benefit of the doubt though, it`s potentially a worthwhile feature.
One can buy the relevant card for ones PC and watch TV on it.
In addition there are a number of radio channels available including R5 Live which is not transmitted on FM, see paragraph above.
Lastly you can buy a Personal Video Recorder (or PVR) which can pause and rewind live TV. From only about £100 you can buy one which will record up to 180 hrs of TV and has 2 tuners to record one channel whilst you watch the other, or record 2 different channels at the same time !
Who needs Sky+ (at great expense) when you can get Freeview+?
PVRs certainly make recording much easier, particularly when using "series link", but it`s not all good news. PVRs do have their down sides. Some are quite complicated to use, they can also be unreliable in recording programmes, occasionally they freeze up and must be hard reset (i.e. switched off then on at the mains....) and if they ever fail completely all the recordings are lost.
Furthermore I think it appalling design that most PVRs (or Virgin + or BT Vision [not the newer black boxes from late 2009 anyway]) don`t have RF modulated outputs, which means you can`t pipe the output of the PVR round the house to watch on other TVs, like you can with Sky boxes (actually you can but you`ll need to buy and fit an RF modulator).
Cynics, like me, would say they only do that to force you to pay for another box.
To be fair, extra PVRs can easily be added to the system, unlike an extra Sky box, but some PVRs are £200, and anyway, if you`ve recorded a programme on a PVR in the lounge and you want to go and watch it in the bedroom, it`s not like a Video where you can just take the tape out.
It`s even worse with Virgin (cable) and BT (BT Vision) because it`s not as easy (or cheap) to source an extra box, and it`s not as easy to add it into any distribution system you may have.
In my professional opinion those companies` designs are so poor that customers should complain to them and get them to pay for any modulator you may require.
Read some more of the manufacturers` pathetic excuses on this Forum thread.
4 The reliability of the digital signal will improve when they turn off the analogue signal at Digital Switch Over (DSO). The plans are to considerably up the power outputs of the main transmitters and transmit 3 of the 6 MUXES (the most important ones, the so called “PSBs”) from all of the smaller repeaters. The latter are the “fill in” transmitters which are used to increase coverage in fringe areas. Note how there are no plans to broadcast all of the Freeview output from all of these relays. When the DSO occurs it is proposed that (wherever possible) these transmitters will stay in their original groups. The switchover for the Borders area reflected this strategy. Of the 61 transmitters in the Borders region only 6 will be broadcasting digital outside of their original groups and in all six cases the new frequencies are below the existing group. This is significant because Yagi aerials are reasonably responsive below their designed for band, so even those
six locations will probably still pick up the digital signal OK !
The frequencies for the repeaters in Anglia, Borders, Central, Granada, London, Meridian, Scotland (Central), Scotland (North), Tyne Tees, N Ireland, Wales, West Region, West Country and Yorkshire have been released by Ofcom. Of all the hundreds of repeaters listed there all but three [including Cefn Mawr in Wales] will probably work fine off existing aerials. Though this is less likely to apply for some cheap crappy Contract aerials though......
As we`ve been saying for years * the great majority of transmitters are reverting to their original groups and unsurprisingly this includes all of the “Big Five” which cover about 30 million of us.
In fact all the existing Digital transmitters will broadcast the main three MUXES (the so called PSBs) within band, i.e. those of us who are quite satisfied with the “basic” five channels, will almost certainly get them with the aerial we already have !
As for the other three MUXES, 24 of the 81 transmitters will be broadcasting between one and three of the other 3 MUXES out of their original group. Fortunately seven of these will be transmitting the new frequencies below the existing group, meaning that those in reasonable signal areas will still have a good chance of picking up the signal OK.
That leaves 17 out of 81 transmitters, and of these only six are “main” transmitters, these being Belmont, Bilsdale, Craigkelly, Sandy, Sudbury and The Wrekin. It must be admitted that for these “Dirty (half) Dozen” an aerial change may well be required in order to receive all the digital transmissions, as opposed to just the PSBs, which will be available from your existing antenna in the vast majority of cases.
So, for the great majority, when the DSO occurs many of those who haven`t yet “upgraded” to a wideband (and most people never needed to do so anyway) should then pick up the Digital signal OK. Furthermore many of those who live in fringe areas can, if required, then take advantage of the superior gain of grouped aerials to improve their signal.
Also see Digital Transmitters Nationwide and Major Transmitters: Which Aerial To Use.
I do wonder how the government are going to end up with spare slots in the RF spectrum to sell off because one only has to look at the Transmitter Channel Allocations for the Sheffield area to see how well filled the RF spectrum is.
For the record the “reserved” channels were 31 to 37, 39 & 40 and 63 to 68, but in 2009 the “800MHz clearance” was adopted. This basically means that CHs 61 and 62 will be cleared of Freeview transmissions but CHs 39 and 40 will be released for it. Thus the “reserved channels are now planned to be 31 to 35, 37, and 61 to 68. This has some unfortunate consequences in that all MUXES allocated to channels 39, 40, 61 & 62 will probably all require reallocating with all the retuning etc that that will entail, also see the Ofcom 600Mhz band document. Basically the MUXES which were on CHs61 and 62 will be moved to CHs 49 and 50, and those which were on CHs 49 and 50 will be moved down to CHs39 and 40. The reason for all this muxical chairs is to keep the MUXEs within the original groups of the aerials, though I have to say it`s probably somewhat unnecessary because I`ve never tested a C/D group aerial which isn`t still working pretty well down on CH39. There is one beneficial side effect of moving some of the MUXES down the band, because grouped aerials generally work OK below there designed for band, so more people may well be able to use grouped aerials post DSO than was originally planned. However, generally speaking, some crappy contract C/Ds might not work as well in this regard ?
By way of recompense, hopefully, when they`re flogged off, these reserved channels are going to raise a decent amount and save us all some tax dollars.....
Ofcom have also identified some ‘spare’ channels which they believe will be available after DSO, possibly for TV transmission. There are two different (potential) plans here, but, as far as TV broadcasting is concerned, neither include CHs 61 to 68.
(Information correct as at December 2011 : Ofcom)
The first is known as “interleaved spectrum” channels. These were originally slated for auction to the highest bidder so they may, or may not, have ended up being used for TV broadcasting. However the government announced in 2011 that they could only be used for local TV stations. It remains to be seen how many will actually get off the ground but that`s the plan.
The full list of the potential frequencies is on p49 (or is it p46 ? ! ?) of this
Ofcom document and It will be noted that the virtually all of them are within same
groups as the previously announced post DSO transmissions. However many of these
interleaved spectrum frequencies will not be transmitted omni directionally or at
full power, due to co-
After switchover is complete a gap from CH31 to CH37 will open up in the UHF transmission spectrum and these frequencies will be auctioned off to the highest bidder. The frequencies may (or may not) end up being used for TV transmission. Great, we`ve got the possibility of even more crap and/or repeated programmes...... If any TV is broadcast in this gap then, by accident or design, they`ve actually chosen this band quite cleverly because all A group aerials will pick it up, most B group aerials would, and even many C/D group aerials (the decent ones anyway) will still work, after a fashion, between CHs 31 and 37 [see aerial group curves]. On the other hand it must be admitted that most C/D group aerials wouldn`t be working at their best at CH31, particularly in a poor signal area. So, if you`re on a C/D group transmitter (e.g. Winter Hill) and you want to "cover all bases", but sacrifice a bit of gain/directivity, go for a Yagi18E (or a DY14WB) rather than a Yagi18C/D.
Pre DSO (i.e. dual analogue digital running) the Digital power outputs are all significantly lower than the analogue ones but the nature of the digital signal means the output levels do not have to be as high to give a noise free picture, i.e. no “grainyness”. Theoretically the Digital signal only needs a 26 dB signal to noise ratio to achieve a “perfect” picture, as opposed to the analogue which requires around 44dB. Thus the Digital signal received at the antenna can be 18dB lower and still give (what passes for) a perfect picture. As an example, Emley`s 10kW Digital output coverage is approximately equivalent (radiation patterns differ between the two) to its 870kW on analogue. I`m not convinced that the power outputs are actually equivalent but in any event they are due to be greatly increased when the analogue switch off occurs. To continue the Emley Moor example its present digital power of 10kW will be increased to 174kW. That`s a big increase, even if one does bear in mind the inverse square law, which means that to get double the coverage you need four times the power, or something like that ! Some frequencies from some of the TXs will only go up to full power towards the end of the DSO in order to prevent interference to areas which haven`t yet switched over. As an example, MUXES 4 to 6 off Caldbeck were originally1.6kW before DSO, were 15kW during DSO, but became 50kW after full DSO.
There is a distinct possibility that many people, particularly those with with aerial amps, may experience cross modulation interference or other deleterious effects when the power is turned up, see variable gain amplifiers. Also see post DSO analogue to digital power equivalance.
5 OK, so you may need to pay for a new aerial (most people won`t though) but you`ll need a new one sometime anyway. Nothing lasts for ever, though some things last longer than others !
If you have a steel pole it will eventually rust through (see Poles), your down lead
will eventually perish and/or wear through (by the action of the wind if it is not
pinned to the slates, see Cable) and sooner or later your aerial will fall apart,
particularly if it is a "Contract" or a poorly constructed X-
See article on finding a decent aerial installer (and tradesmen generally).
High Definition TV is about more detail in the picture, and this is great when you`re watching the set from a few feet away, which is precisely the distance you`d see it from in the shop whilst the salesman tries to sell it to you. There is no doubt that HD has a better picture than standard digital and even (good) analogue but for the average size set I have my doubts about how much of the extra detail you would actually see from the normal distance which you would watch TV from. As an example, if you had a 28” TV and sat 10ft (or more) from it then most people would not see any difference in the picture over a (good) analogue 625 line resolution picture. There is no question that High Definition TV would be worthwhile if you had a screen the size of your wall but I`m unsure how many people would actually want a TV of that size. I suppose it would at least save on having to redecorate that side of the room and bearing in mind that these days anyone who doesn`t have a "House Makeover" every other month is considered abnormal (Home Makeovers, the new Rock & Roll ?, count me out....) this could save a considerable amount of time. This saved time could then be used to put in extra hours at work which would then help pay for the expensive wall sized TV you`ve just purchased, and so the circle is closed. Isn`t the symmetry of life beautiful ?
My advice is don`t bother talking to anyone or spending any time researching HDTV. Go down to the shop, try to be impartial (sub conscious influences, it looks very swish therefore it must be better....) and ask to see the set on showing a football match next to a SD TV.
Watch the picture from the same distance you would normally do so at home and then make up your own mind mind, but remember to bear in mind that (on either Freeview, Cable or Satellite) only a small percentage of all the channels will be High Definition anyway !
Having said all the above, and liberally taken the piss (you wouldn`t expect anything less, surely), when the switchover comes the superior analogue picture (superior to “standard” digital that is) will no longer be available. So, if and when my trusty 1988 B&O 21” TV (it`s really only a Ferguson/Thomson in disguise...) finally expires I may well get an HDTV.
That`s mainly because I`m a TV engineer (an ex TV engineer) and I`d constantly be looking for all the imperfections in the standard digital picture [esp on the more compressed channels]......
But I won`t pay any extra for HD, no way ! Why ? Because by then the three (later four) promised Freeview HD channels will have started broadcasting !
HD on Freeview (originally recommended by Ofcom in Apr 08) will consist of one MUX being given over entirely to HDTV, and the programmes which were originally on it then squeezed onto the other 5 MUXES. Note how this would not require any more wideband aerials to be installed than are currently required, or not as the case my be.... However, even using an entire MUX for HDTV will only give three (later four) HDTV channels and this would be at the cost of increased compression (i.e. a worse picture) to all channels moved onto the other MUXES.
Oh yes, and you`ll need a new box as well.
No Freeview box/TV on the market before spring 2010 will decode the HD signal.
This raises interesting questions as to whether the TV you bought as "HD ready", has been mis sold to you. I`m sure the courts will end up deciding that little one.....
Personally I think they`d have been better advised using the additional bandwidth to improve the quality of the standard picture and increase the error correction content of the signal (see Digital Cliff Edge) and thus make it more robust and less likely to freeze and pixellate. I suspect there are millions of people in marginal signal areas who would agree with me.
Whatever happens there won`t be a huge number of HDTV channels on Freeview, or any
other system, because there simply isn`t the bandwidth for it. You may get a few,
but probably not that many, and definitely not all of them. HD began broadcasting
the three HDTV MUXES as DSO occurred in each area (starting with Granada -
But, to be fair, what comes first, the chicken or the egg ? ! ?
From early/mid 2010 as the transmitters switched over they started transmitting HD
on MUX3 (e.g. Mendip in Mar/Apr 2010), with those that had already switched (e.g.
Stockland Hill) being phased in over time. Some of the larger transmitters (Emley
Moor, Pontop Pike, Lichfield [ = Sutton Coldfield], Crystal Palace & Black Hill)
started low power HDTV transmissions in 2010 in advance of their full digital switchover.
Some of these initial transmissions were be subject to restrictions in certain directions
due to co-
(All sourced from Ofcom, Sept 2009)
The government want to sell off the spare slots in the spectrum (which could have been used for more HDTV at DSO) and, to be honest, if it`s going to save me paying some tax they can go ahead as far as I`m concerned.
You can get HDTV through Sky though unsurprisingly the grasping Murdochs will require you to pay extra. For all that outlay not all the receivable programmes are available will actually be in HD. The actual number keeps changing so check with Sky as to the latest situation. NTL/Virgin Cable TV also do HDTV, but again not all programmes are in HD. Oh yes, and you will require different STB, at extra cost naturally, haven`t I just said that.......?
In May 2008 the BBC (and ITV) launched a free to view satellite platform which is carrying some HDTV, but it will suffer from all the additional complication/expense involved in satellite reception.
NOTE ! You`ll only get an HD picture if either :
1 You`ve got a TV with built in HD (i.e. one purchased after Spring 2010), not an “HD ready” TV bought before that time, in which case will require an external HD Freeview box (see 2).
Many "HD Ready" TVs purchased before this date will appear not to receive any signal on the frequency that HD is being transmitted on. So, if you get good signals on the 5 other MUXES, but nothing at all on MUX3 (the HD MUX), how old is your TV ?
2 Your TV is “HD ready” and connected to your HD box via an HDMI lead and the TV is switched to the HDMI AV input. If the TV is just connected by SCART, or by the RF (i.e. through the tuner, as all distribution systems are) you should still get a picture but it won`t be in HD !
We are more than willing to give advice to those actually purchasing from us.
Could those only seeking information please just find the answer somewhere on this site,
or ring an aerial installer local to them, or call the reception advice phone numbers.
A Digital TV picture (as in standard definition, not High Definition) is NOT superior to a good analogue picture. In fact (and "the powers that be" are very quiet about this) it`s actually worse. Because the broadcasters want as many programme channels as possible they have sacrificed picture quality (and a robust signal) to that end. A good (I must stress that word) analogue picture can take advantage of its greater bandwidth to give more detail and a "higher refresh rate" to the picture. I accept that one has to look closely at the picture (or be an expert) but a digital picture is worse, though some digital channels are worse than others, it`s down to the amount of compression used for that particular transmission. Look at the fine detail (particularly on a moving shot, a football match is a good example) and one can see it "blocking". Even more annoying, to me anyway, one can sometimes see the staccato movement associated with a low refresh rate. All the inferior picture qualities of Digital (plus a few more) are also present on LCD or Plasma Televisions.
The graph on the right shows how the relative picture qualities of the analogue and digital systems vary as the signal quality deteriorates.
Note how with a perfect signal the analogue picture is superior to digital (not HD), then falls behind as the signal quality degrades, before retaking the lead when the digital signal runs out of error correction data and falls precipitously down the ”Digital Cliff Edge”.
Note that the quality of the [SD] digital picture can vary according to programme, some (mainly the crappy, “all repeats” esoteric ones.....) are more compressed than others.
The “powers that be” keep changing the name of the MUXES, so we just refer to them as MUXES 1 to 6, as they should be anyway....
Don`t you just hate all this name changing b****x ?
Pre DSO : Programme to MUX allocations (For England, updated 10 Aug 11)
MUX 1 = BBC1 & BBC2 + BBC3 + CBBC + BBC News
MUX 2 = ITV1 + ITV2 + C4 + C5 + More4 + E4 (Note Film 4 is on MUX 6)
MUX 3 / A = ITV3 + Top Up TV 1 & 3 + QVC + GOLD + Bid TV + CITV + Five USA
MUX 4 / B = BBC4 + BBC Parl + CBeebies (+ BBC Radio 1, 2, 3, 4, 5 & World S+ BBC Asian N)
MUX 5 / C = Dave + Sky News + E4plus1 + Price Drop TV (+ Talk Sport Radio etc )
MUX 6 / D = Yesterday + Film 4 + The Hits + Top Up TV 4 + Ideal World
For a comprehensive up to date list go to www.dtg.org.uk/retailer/dtt_channels
(England is the 1st column, Wales the 2nd, Scotland the 3rd & N Ireland the 4th)
Post DSO : Programme to MUX allocations
MUX 1 / BBC A = Main BBC channels
MUX 2 / D3 & 4 = Main ITV, C4 and C5 channels
MUX 3 / BBC B = Three (eventually four) HDTV channels (initially BBC1, ITV & C4)
MUX 4 / SDN = ITV3 + Top Up TV + QVC + Gold + Bid TV + E4 + FIVE USA
MUX 5 / Arqiva A = Dave + Sky News + Pick TV + E4 plus 1 + Price Drop TV
MUX 6 / Arqiva B = Yesterday + Film 4 + ITV4 + Ideal World + 4Music
For a comprehensive list go to www.dtg.org.uk/industry/dtt_channels.html#post
Note. The first three MUXES are known as PSBs (Public Service Broadcasting) and as such they receive higher priority in the allocation of channel space, or frequencies within a particular transmitters original group. Furthermore, from 2012, MUXES 4 to 6 (the COM MUXES) will have a bit less error correction data than the PSBs
Post DSO the PSBs will be the only ones broadcast by the smaller repeater transmitters. However, it should be bourne in mind the three PSB MUXES contain all the “main” channels (including the 3, later 4, HD channels).
And let`s face it, most of the rest are either repeats, or rubbish.....
Digital TV
Note, as work takes place on various digital transmitters (to prepare for the DSO) you may experience problems, e.g. with certain MUXES disappearing. First try rescanning your TV/set top box (do it manually if possible), but if this fails to work check on transmitter work,
or call the reception advice phone numbers. Also see basic digital fault finding.
Some people will need their aerial and/or downlead changing. This can mean swapping to a wideband antenna but for most people it does not, they will get a perfectly good signal off their existing grouped antenna. In fact, in poor signal locations, grouped aerials actually work better anyway Some houses are in such poor locations that they will never get decent terrestrial digital although it should get a lot better after DSO.
Unfortunately some people will have no alternative but to go down the "Freesat/Sky" route.
Or there`s Cable TV but that has its own drawbacks as well.
Incidentally, I would always advise anyone with Sky to have a back up aerial. Not
only will it mean you can feed any number of TVs or PVRs (capable of tuning independently)
but if your LNB / Dish / STB fails you will still get the basic analogue 5 channels
plus (for most people) Freeview. We regularly get customers phoning us up in desperation
at Christmas, their Sky has stopped working and no-
The Digital signal is not as robust as the analogue one. An analogue signal can be really quite poor and one will still get a watchable picture. It may be grainy, and maybe even ghosting as well, but when Mr Rooney sends a right foot pile driver towards the top left corner of the Brazilian goal in the 2010 World Cup final (sorry, out of date, 2014 cup final, then the 2018 then the 2022 etc.....) you will see it go in (or not....).
A digital signal will not degrade in the same manner. Generally you will either get (what passes for) a perfect picture, or you`ll get very annoying blocking/freezing, or you won`t get anything at all. Sods law being what it is (if you live in a marginal area) this picture loss will occur just when you really, really, don`t want it to.
Did he score ?
Did we win the World Cup ?
Of course we didn`t, what are you, a fantasist ?
Digital transmissions have in-
To be perfectly honest you will always get the odd signal “glitch” (freezing etc) with Digital signals and that applies to Sky as well as terrestrial. All you can do is try to limit it as much as possible by maximising the quality of your signal, see graphic.
When the Digital Switch Over (DSO) occurs those with Portable TVs running off “set
top” aerials are likely to be affected in the most negative way. Many people use
portables in upstairs rooms (with no connection to their outside antenna) and put
up with a less than perfect -
* The amount of error correction data (known as FEC, or Forward Error Correction) is being reduced on COM MUXES during 2012. This is so the broadcasters can squeeze more programmes onto each MUX. This is, I`m sure you`ll all agree, absolutely fantastic !
We`ll get even more crap and/or repeated programmes, which are more likely to break up whilst we watch them. Now I don`t know about you, but I love life.
Note, the FEC reduction will only be occurring on the COMs (MUXES 4 to 6), not the PSBs (MUXES 1 to 3) and, if it causes a problem, it can usually be overcome by a better aerial install.
Most people already have (or had) Teletext and this was a digital system, so was Nicam stereo. Both of these demonstrated the same type of failure mode as digital TV, and also the importance of a decent signal / aerial system because it is deficiencies in reception which were the most likely cause of problems with either Teletext or Nicam.
Teletext is particularly relevant when it comes to error correction data. The header line had significantly more of the latter than had the main body of text. This explained why even when most of the page was a meaningless collection of random letters the header line could still make a reasonable amount of sense. And in the case of Nicam many TVs had the facility to switch it off (and revert to the original FM sound) if the signal level degrades to the point where drop outs are excessively annoying.
This is perhaps the ultimate proof of the more robust nature of the analogue signal .
4 Every conventional (i.e. analogue) TV or video will need its own Freeview "Set Top Box" (STB) if it is to continue working when they turn off the analogue signals. It is quite common to come across people who find the setting up/retuning of the Freeview boxes or TVs somewhat complicated, in fact part of our business is "setting up" customers systems.
Worse, the days of tune in once then forget it could be numbered. Much swapping about of MUXES may well happen over the years, and every time that`s done your box/TV will need retuning. There are also due to be many retunes required during and after (and sometimes before! ), the actual digital switchover.
5 In our experience Digital tuners are not the most reliable * pieces of modern technology and they aren`t really repairable either. That`s not a big deal if it`s a separate "STB" which has failed (they aren`t that expensive) but if its built into your TV then that`s a rather different story...... It was possible to economically repair around 80% of conventional TV`s (i.e analogue, non LCD, non Plasma, non Rear Projection) but with integrated sets it`s far lower than that, see Repairs. That`s why, whilst thet were available, we advised people to buy an analogue TV and a separate set top box. Doing it that way is more flexible as well. Furthermore, until they turn off the signals at DSO, the analogue channels can be a valuable diagnostic tool for tracing signal faults or indeed when “peaking up” your aerial at installation. Signal fault finding on analogue is far easier than with digital signals.
* The most effective way to increase the reliability of your STB (or any piece of electronics)
is to keep it cool, i.e. do not place it in an enclosed area on top of a video.
Remember any TV will work with a digibox (provided the latter has an RF output) so don`t be forced to buy a new TV when you don`t have to. One last thing, there have been rumours that the Digital system may be changed at some time in the future from from MPEG 2 to MPEG 4. If were to occur than all the integrated sets could then become obsolete or at the very least require a STB feeding them through the SCART socket. So that`s yet another reason to go with a separate STB in the first place.
Some of the oldest digiboxes and digi TVs will gradually cease to function from Summer 2008 when the broadcasters "Split NIT" network changes occurred. Note this will only become apparent when the digi box is retuned, as they occasionally have to be, like on the 30 of Sept 2009 when C5 moved from one MUX to another.
There are also a number of models of digibox/IDTV which won`t work after switchover because the transmission mode will change, from 2K to 8K. Just to clarify that, the 2K/8K problem will only become an issue when your transmitter actually switches over, e.g. Crystal Palace won`t be until 2012, (source Ofcom 30 Sept 2009).
There`s one last advantage to an analogue TV with a separate STB (or at least a digital TV which also has an analogue input) in that many people add the signal from their Sky box to their distribution system and the same with the signals from their CCTV cameras. They`re both analogue signals modulated onto UHF frequencies. What`s going to them with a digital only TV ? They won`t work ! It must be admitted that the vast majority of digital TVs sold up to press are still analogue compatible, but still, it`s something to remember.
Incidentally, different models if STB (or indeed digital TV) have differing tuner sensitivities, and it`s not always the expensive ones which are the best either ! We`ve had customers tell us they`ve got significantly more reliable digital pictures by simply changing the STB.
See : Basic digital fault finding.
6 Let`s be honest, nearly all of the additional programme channels on Freeview (or Freesat) are either repeats, or they`re just rubbish. I know that`s a subjective opinion but I suspect most people would agree with it. Actually, come to think of it, it`s not a subjective opinion at all, most of the programmes are repeats ! (see below). And quality wise there is an inverse proportional law about TV, the more programmes there are, the worse they are. I`ll resist the temptation to give my opinion on producers who try to make their programmes more interesting by using “5 second attention span” editing, one can only assume it`s aimed at kids with attention deficit disorder.
Hold on, I`ve just realised, I haven`t been able to resist the temptation, sod it.
If they continue increasing the number of channels there will eventually come a point where it takes longer to go through the TV guide very week, than actually watch the bleedin` programmes. Whisper it quietly but there really are far more interesting things to do than watch TV, though these days “Health & Safety Bollocks” seems to try and to put the mockers on most other things......
I tried to avoid getting digital for as long as possible, because the wife spent far too long watching TV even when only five channels were available.
Let`s face it, she should be giving me more attention.
And doing more housework, obviously.
Remember, a wife isn`t just for doing the cooking.
She`s for doing the cleaning as well.
Only joking girls !
The comments on extra TV channels obviously doesn`t apply if you`re a sports or film fan,
but you won`t (generally speaking) get much of either of these on "Free to View" TV.
Quote from the Radio Times :
“ALL PROGRAMMES ON DIGITAL CHANNELS ARE REPEATS UNLESS STATED OTHERWISE”
Nuff said......
When I last checked the Radio Times no longer gives this information, not prominently anyway, but when I questioned why they said the`d look into replacing it. Time will tell.
Ahh, it`s back, for now anyway.......
Incidentally (analogue) FM radio and (digital) DAB radio follow the same kind of pattern.
Proposed Digital Switch Over (DSO)
For dates of the individual transmitters see Digital Nationwide
Note these dates, if you are going to have any work done on your aerial system I wouldn`t wait until the last minute because at that point in time the laws of supply and demand will not be working in your favour ! That said, read section 4, including increased power.
2008 Cumbria & Borders.
2009 SW England, Wales & NW England.
2010 West of England & N Scotland. (Note that Borders is 2008).
2011 Central Scotland, Midlands, Yorkshire & East Anglia.
2012 Ulster, NE England, London, South & SE England.
Note how the planners have cleverly arranged the last date to coincide with the London Olympics. I`m sure it`ll be OK, well probably.......
See Digital UK`s "When Do I Switch ? " , Transmitter Groups, & Full Switchover List pages.
How will the switchover actually be done ?
The switch will always occur mid week (usually on a Wednesday) in order to give people time to sort out any aerial work they need before the weekend. In almost every case it will occur with analogue BBC2 being switched off first and at the same time the (low power) pre DSO MUX 1 [the main BBC channels] being switched off as well. MUX1 will then be reallocated to its post DSO frequency (often that vacated by analogue BBC2) and at its new, much higher, power.
Two to four weeks later the rest of the analogue channels will be switched off and the other MUXES reallocated to their new frequencies at their (higher) post DSO power. There is no technical reason for this phased switchover, in fact it`d be easier for the broadcast authorities to do it all at the same time. It`s to give Joe (or Joanne) Public a chance to sort himself (or herself) out, to get a box if needed or upgrade their aerial, whilst they can still get the other 3 (or 4) analogue channels apart from BBC2 [which will have been switched off].
That said, due to co-
Even that may not be the end of it for some unfortunates. There`s a distinct possibility that future swapping about of the MUXES and frequencies may well occur...... What`s more, if you`re on a communal TV system, many of them will require hardware changing up at the distribution board every time new frequencies are required. Depending on the efficiency of your landlord/agent you may not get that done straight away, i.e. you may well be without some channels for a while.
Note that at the switchover not all MUXES will go straight to their full transmission powers. Most PSBs will, but in many cases MUXES 4 to 6 won`t, though Digital UK don`t publicise this very well, if at all (slap on the wrist for them), so, if wondering whether some of your MUXES will get better later, or not, patience is a virtue..... Officially Digital UK say that any transmitter which is to undergo a post switchover "COM power up"will only be transmitting those MUXES at the its pre DSO power level until that time. Even though that`s not actually always the case.
At every stage of the process all Freeview digiboxes and TVs will need retuning, and try to do so after 6.00PM, when all works at the transmitter should be completed.
If you have to employ someone to come and retune your box it`s worth considering whether you can do without some of the channels after the first retune event and just pay for an engineer to call when the second retune is required.
Incidentally, try not to be a cheeky git, phoning up a retailer for free retune advice if you didn`t actually buy the TV from him ! If he tells you to “sod off !” he`s quite within his rights. We sometimes get these kind of people phoning us, you should only ask advice from the supplier where you spend your money. After all, how would you like it if the positions were reversed ? ! ?
Alternatively phone reception advice.
Remember they`re paid to advise you, unlike the above mentioned chap, or us........
The golden rule is, if having problems with your digital TV, FIRST TRY RETUNING IT !
If possible delete all the existing tuning, then try a full retune.
Retuning help available here www.tvretune.co.uk and on telephone number 08546 05 11 22
Digital Multiplexes (MUXES) / PSBs
The Digital system (at a loss of some quality and signal reliability......) can broadcast up to 20 programmes per transmission channel. Each one of the latter is called a Multiplex or MUX for short. The channel numbers/broadcast frequencies of a number of the main transmitters can be found using the Nationwide Transmitters page, also see Digital UK`s regional transmitters, it`s set on Yorkshire but the others are available via the drop down menu.
The basic programmes found on each MUX are listed below. This information can be used as a diagnostic tool to identify where faults may be on the system. For example if blocking/freezing tends to occur on programmes of the same MUX (but the other MUXs are OK), then the problem is almost certainly a signal or “set up” fault rather than the box, see Digital Cliff Edge. On the other hand if all the MUXES are affected (and your analogue channels are OK * ) it`s far more likely to be a faulty box, or an incorrectly set up system. Also see digital multiple transmitter reception.
* If still being transmitted. Use the Digital Nationwide list to check if the digital MUXES in your area are spread across same group as the original analogue channels. The same basic rules apply though, even if just one of the MUXES is received perfectly but the others are not, it is most likely to be a signal or “set up” fault.
Do not discount the obvious ! I can remember when the ITV channels started breaking up on one of our PVRs (digital recorders) but the BBC channels were fine. At the time MUX1 as at much higher power than MUX2, so I put it down to that, until my wife started complaining, so I felt I had to try and sort it out, you know how it is........ I was amazed to find that the lead into the affected PVR had nearly fallen out. It was incredible it worked at all. Still, it was easy to repair the "fault", and the wife was impressed I`d fixed it, so what more can you say !
The next step is to pull everything out (having made sure you draw a diagram of where all the cables go back in, obviously.....) and connect the lead direct from your aerial straight into your STB or digital TV. For the purposes of this diagnostic test it is very important that the signal from the aerial isn`t going through anything else (like a Sky box for instance) before being plugged into your digital STB. Does the fault disappear ? If so find the cause by elimination.
Still faulty ?
Well at least you`ve eliminated a lot !
Incidentally, different models of STB (or indeed digital TV) have differing tuner sensitivities, and it`s not always the expensive ones which are the best either ! We`ve had customers tell us they`ve got significantly more reliable digital pictures by simply changing the STB.
If after trying all the above you`re still in doubt as to if the fault is the signal or the box I`d swap round the digiboxes/TVs (or even consider buying a another STB) and trying that by substitution. It`d be cheaper than calling someone out to check your signal !
Use of a “hard reset” (technical name for pulling out the mains plug for a
minute or so....) is often successful at “rebooting” a locked up digital TV or STB,
and this is especially the case with PVRs/hard disc recorders.
Don`t forget to check your TV (or box) is tuned in correctly, and to the
most suitable transmitter. It may be necessary to tune your TV in manually
or at least do a “Full Scan”, as opposed to “Add Channels”. Be bold, do not be dissuaded if you get a message warning you will delete existing channels !
Some boxes allow you to delete all channels before you do a scan, and this can be particularly helpful if you`re suffering from transmitter overlap and you want to reorder the channels on your TV. A few boxes/TVs, notably some Humax, require you to go into the channel list and manually delete all channels before then doing a rescan, otherwise they just add more channels on, leaving the incorrectly tuned ones also on the list ! Why on earth did Humax put that feature on ? If your TV/STB hasn`t got a delete channels function you could try pulling out the aerial, then doing a “Full Scan” (to try and delete everything) then replace the aerial and repeat “Full Scan”.
Particularly if you`re doing your first rescan after switchover and having problems, but it worked OK before, it may be that your TV`s tuner is overloaded, remember the signal strength has just gone up a great deal. In fact you may even need an attenuator, or if you have an amplifier, try removing it. Note, many TVs/Set Top Boxes indicate no signal (or low signal), even when the actual fault is excessive signal ! I had this very problem at the shop.
If desperate try a factory default/reset, though this may well delete all your recordings if you have a PVR, so be warned......
Finally, some TVs and boxes (particularly PVRs) seem to take time to sort themselves out. I don`t know why. So if you`re only getting one set of channels (i.e. you`re not suffering from transmitter overlap) but the channel numbers are all to cock, try leaving the box for a day or two after your full retune. They sometimes sort themselves out !
“FreeSat” (Free To Air Digital Satellite)
Freesat is transmitted from the same satellite (Astra 2D 28.2°E) as Sky. This is important because it means that any dish which was installed for Sky should pick up Freesat !
Those who live in an area which can`t get Freeview (terrestrial digital through your aerial) have no choice but to go down the “Freesat” route, that is to say through a satellite dish.
The thing is, are you sure you can`t get Freeview ? We`ve had customers come in to us saying they can`t get it in their area, we look on our installs map (more accurate than the Post Code checker....) and we`ve done digital install jobs on their road, no problem !
That said, there are sites which will struggle, though most should be OK after the DSO.
Freesat is a completely different system from Freeview
and the STBs are not interchangeable.
When I last looked Sky would supply and fit the system for about £150. This seems quite
reasonable against the cost of a decent quality aerial installation (though you obviously have to pay through the nose for the programmes.....). In fact if a more sophisticated antenna/amplifier is required then Freesat may actually appear to be cheaper. In May 2008 the BBC (and ITV) launched a free to view satellite. Unfortunately that is not the whole story and for the reasons listed below I would strongly advise anyone, who has any sort of option, to go for the Freeview system.
Obviously those who actually want the pay channels may need to go for Sky or Cable, though Top Up TV is available through your aerial.
1 Set top boxes (STBs) for Freeview are available from around £15 upwards and can be obtained virtually anywhere, even at the supermarket. Sky satellite boxes are about 3 or 4 times this price and are rather more difficult to obtain as well. Freesat boxes are quite a bit cheaper than Sky boxes, and easier to buy, but they still don`t sell them down my local Morrisons.
2 Although we don`t recommend their purchase (see unreliability of Digital tuners) sooner or later all TVs/Videos etc will probably be integrated. That is to say they will have a Digital tuner “built in”. For these to work you will need a Terrestrial Digital (i.e. Freeview) signal. Most of those on Freesat will still require a separate STB for every set.
3 Many homes have TV aerial distribution systems fitted so as to get decent signals to all the sets in the house. Assuming it is of reasonable quality (or you are just lucky ! ) the system should be compatible with Freeview. Since the signal is at UHF frequency it may even work with the kind of budget low specification cable that house builders (and some aerial installers......) put in as standard. Satellite distribution systems (i.e. signals from the dish to a number of STBs, rather than from one STB to a number of TVs) are very much more complicated and expensive.
Because the satellite signals are at much higher frequency than the Freeview UHF signal it is unlikely that the type of low quality cabling mentioned above would suffice, so you may even require your house rewiring too. If the cable is run in the walls that is obviously rather problematic to put it mildly.
4 Heavy rain or snow (remember that ? ) can degrade the picture, possibly giving no picture at all for powerful persistent precipitation (I love alliteration). I was reminded about this during a phone conversation with my brother in New Zealand, and he said they had no (Sky) TV because they were suffering from heavy snow ! I accept that the same can happen for Freeview in marginal areas but you can often do something about that by using a higher gain aerial. The vast majority of people will just use the standard 43cm mini dish supplied by Sky, and wouldn`t usually want a 60cm or 80cm dish on their property, even if one of these were an option.
5 If you`re using the Sky free channels (as opposed to Freesat) in order to receive all the available free channels you will need a Sky card . At the moment this is quite cheap but it is only available from Sky and anyone who has had dealings with them can testify that it can be a frustrating business..... In fact when Which? researched call centres in Jan 11 they found Sky was the worst, and they`ve got some decent opposition in that department, particularly Royal Mail, and (ironically) BT, plus all the broadband providers, obviously. That`s the modern trend, companies don`t actually want to talk to their customers, not unless it`s a voice activated computer. I never talk to them. Well actually I do, I swear at them till they put me through to a human being. You should try it, it`s very satisfying.
Some of the of the programmes on Freeview are not available on Freesat. As far as I am aware Dave or the UK History channel are not available on Freesat although the situation could change so you are advised to check. Apparently UKTV History changed its name in March 09 to “Yesterday”, and it also changed its Freeview MUX allocation. Yet another example of name changing bollox. Isn`t all this digital TV complicated enough......
On the other hand there are a few more channels on Freesat than on Freeview.
So you might get 120 odd channels of crap *, instead of the 80 odd channels of crap on Freeview.
Big deal.
At least you can waste even more time going through the TV guide confirming there`s nothing actually worth watching anyway. Life`s wonderful.
* Remember they aren`t all TV channels, some are radio channels.
Who listens to the radio through a bleedin` satellite anyway ? That`s what I want to know. Whatever next ? Gas companies selling electricity ? And I bet they`d charge too much for it.
The world`s gone mad.
The third option for Digital TV is Cable, of which NTL Telewest was the main supplier though it`s now called “Virgin Media. (Don`t you just hate all this name changing b****x ?)
As with Sky it is a completely different system and the STBs are not interchangeable for either Freeview or Sky.
Cable is similar to Sky in that it has far greater bandwidth (by utilising fibre optic cable) and “Pay To View” is available should you want it. Unfortunately it also has many of the disadvantages of Sky. A separate STB is required for each TV (and always will be) should you want to watch different Digital channels on different sets, though as I understand it Virgin do pipe the five basic channels through the system, so on the second set (or the video) you have the choice of those plus whatever is selected on the STB. Originally the STBs themselves could only be rented (not purchased outright) but I`m told you can now buy them for £50, but there`s a £100 installation charge, plus they still charge you an additional £10 per month, every month (obviously), not sure why, but there we go.
For details of the implications of splitting a Cable signal (i.e. to the STBs rather than from one STB) see relevant article in the Appendix. As for splitting the signal from a Cable box (to multiple TVs) one other disadvantage of (some) cable boxes, is no modulated RF out, which means you can`t send the output of the Cable box around the house, like you can with a Sky box. In my professional opinion that`s just poor design, and if it were me I`d get onto Virgin and ask them to pay for the cost of an external RF modulator, which is what you`ll need to buy to do what you should be able to do without one.......
You`ll obviously have to find out for yourselves but I`ve heard some cringe inducing tales about how difficult it can sometimes be to get through to them on their customer service telephone line. In fact the Which? report of Jan 2011 says they`re nearly as bad as Sky, and that`s bad.......
I always think it`s worth checking any potential suppliers phone service before you commit yourself to them, and not just the sales line !
There is one definite advantage over Satellite though, no bleedin` dish on your wall !
Digital picture quality (worse, for some people)
"Digital cliff edge" including "error correction" (FEC)
Unreliability (and unfixability) of digital sets
Extra programmes ? It`s all repeats anyway !
Do I need a new aerial ? including :
Digital Negatives including :
Subjects on this page are listed in the following order :
Digital Positives including :
Freesat (Free To Air Digital Satellite)
High Definition TV (HDTV) including : What exactly does HD Ready mean.......
Digital Multiplexes (MUXES) including :