I stumbled upon this will looking for some info on upgrading my TV aerial.
I think it’s worth a copy and paste here because it’s the sort of information not always given, and the writing style is entertaining too. Taken from A.T.V (Aerials and Television) with whom I have no connection.
I think it’s worth a copy and paste here because it’s the sort of information not always given, and the writing style is entertaining too. Taken from A.T.V (Aerials and Television) with whom I have no connection.
Digital Myths
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...) 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 £25) but all TVs will work with a Digital Set Top 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 recommend that you continue to buy an analogue TV and use it with a Set Top Box.
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.
Digital Negatives
1 A Digital TV picture is NOT superior to a good analogue picture. In fact (and "the powers that be" are very quiet about this) it is 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 it`s greater bandwidth to give more detail and a "higher refresh rate" to the picture. I accept that one has to be an expert, or to look very closely at the picture, but a Digital picture is worse. 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.
2 Some people will need their aerial/downlead changing. In this area that often means swapping to a wideband antenna. Unfortunately, in some poor signal areas, this can result in worse analogue reception, plus the cost of it of course ! Occasionally it can be helpful to use a second aerial on a different transmitter to achieve the best of both worlds.
Some houses are in such poor locations that they will never get decent terrestrial digital and they will have to go down the "Freesat/Sky" route, Boo Hiss. Yes, you aren`t the only one who hates Sky ! Or there`s Cable TV but that has it`s 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 tape one programme whilst watching another but if your LNB/Dish/STB fails you will still get the basic 5 channels. We regularly get customers phoning us up in desperation at Christmas, their Sky has stopped working and no-one can get out to repair it for 3 or 4 days....... You have been warned !
3 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, 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-built "error correction" (though many people feel there isn`t enough of it...) which can overcome a certain amount of signal degradation. However, once that error correction data has been exhausted the picture has no alternative but to fail spectacularly. This is known as the "Digital Cliff Edge". This is why one should go for the best aerial, the best cable and (if required) a decent screened amp/splitter. Any one of these may (normally) only make a marginal difference, but if they keep your signals on the right side of that "cliff edge", then for what they cost, it`s an excellent investment.
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.
When (if....) 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 use portables in upstairs rooms (with no connection to their outside antenna) and put up with a less than perfect - but acceptable - picture. Unfortunately, unless they live in areas with a reasonably strong signal, they may not get much worth watching after the DSO......
You may well find that the BBC channels are slightly more robust because they use a different method of transmission, 16 QAM rather than 64 QAM. This is at the cost of fewer channels per MUX but I think it was a wise decision to use it. Having said that, the most likely cause of superior BBC channels is because they are often broadcast within the original transmission group of the transmitter and your aerial may require changing to improve the reception of the other channels, see Digital Transmitters Nationwide.
Most people already have Teletext and this is a digital system, so is Nicam stereo. Both of these demonstrate the above mentioned modes of failure and also the importance of a decent signal / aerial system because it is deficiencies in reception which are 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 has significantly more of the latter than has the main body of text. This explains why even when most of the page is a meaningless collection of random letters the header line can still make a reasonable amount of sense. In the case of Nicam many TV`s have 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 (ie analogue) TV or video will need its own Freeview "Set Top Box" (STB) if it is to continue working when (if...) they turn off the analogue signals. It is quite common to come across people who find the operation of the Freeview box somewhat complicated, in fact a significant part of our business is "setting up" customers systems.
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...... We can economically repair around 80% of conventional TV`s (ie analogue, non LCD, non Plasma, non Rear Projection) but with integrated sets it`s rather lower than that, see Repairs. That`s why we advise people to buy an analogue TV and a separate set top box. Doing it that way is actually cheaper (at the present time) and it`s more flexible as well. Remember any TV will work with a digibox (provided the latter has an RF output, which most do) 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 an STB. So that`s yet another reason to go with a separate STB in the first place. You have been warned......!
* The most effective way to increase the reliability of your STB (or any piece of electronics) is to keep it cool, ie do not place it in an enclosed area on top of a video !
If you do have any trouble with your Freeview signals the first thing to try is a “rescan†of your set top box and this can usually be accessed in the installation menu. Next try pulling out the mains plug, wait 5 or 10 minutes then put it in again. If it`s still playing up (and it isn`t a signal fault) then throw it in the bin...... (also see What is an “old†TV ?)
6 Let`s be honest, most of the additional programme channels on Freeview (or Freesat) are either repeats or they`re rubbish. I know that`s a subjective opinion but I suspect most people would agree with it. 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, oh well.......
Then there`s gravitas, whatever happened to that........ Whisper it quietly but there 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......
The comment 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.
Digital Positives
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".
2 The sound quality is “near CD qualityâ€. 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 socket (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 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 the Athens 2004 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, 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.
4 The reliability of the Digital signal will improve when (if....) they turn off the analogue signal at Digital Switch Over (DSO). The plans are to up the power outputs of the main transmitters and transmit 3 or 4 of the 6 MUXES 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 planned switchover for the Borders area reflects 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. Since Yagi aerials are reasonably responsive below their designed for band, this means that many of those locations will probably still pick up the digital signal OK !
The frequencies for the West Country and Granada repeaters were released by Ofcom on the 12 Jul 07 and follow a similar policy. There is a list of “post DSO†channels for all the repeaters but as far as I`m aware many of these have yet to be confirmed by Ofcom.
THIS IS IMPORTANT !
On the 5 July 07 Ofcom released the planned “post DSO†channel allocations for the 81 transmitters currently broadcasting digital and full details can be found by clicking on this link.
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, ie those of us who are quite satisfied with the “basic†five channels, will almost certainly get them with the aerial they 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 Sandy, Sudbury, The Wrekin, Bilsdale, Craigkelly and Belmont. It must be admitted that for these “Dirty (half) Dozen†an aerial change will almost certainly be required in order to receive all the digital transmissions, rather than just the three PSBs.
For the great majority, when the DSO occurs many of those who haven`t yet “upgraded†to a wideband 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.
* There aren`t many others who have been telling people about this because there are so many vested interests who would rather the Great British Public didn`t know this little snippet of information, ie that the vast majority of locations will get all the Digital channels without an “upgrade†if they just wait till DSO.
Think about it. The aerial installers don`t want to publicise it because they`ll lose work.
The aerial manufacturers and retailers don`t want to publicise it because they`ll lose sales. Even the BBC don`t want to publicise it because it`s part of their remit to increase the uptake of Digital now, not at (or after) DSO. It`ll be interesting to see how many others come clean about this vital piece of information now that it`s confirmed. Unless I`ve missed something the “Digital Television Group†didn`t even put this highly significant piece of information on their “Latest Newsâ€........
