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frequencies of DTT muxes after switchover - do aerial riggers know?
I was reading this document...
http://www.digitaltelevision.gov.uk/...odpractice.pdf and came across this paragraph on page 19, just after an explanation of "grouped" aerials, and the need to change them in some cases for current DTT broadcasts... "After switchover, while all public broadcasting services will remain in the same group as before, this might not be possible for some other digital channels. An appropriately qualified local installer should be able to advise on the best type and group of aerial for each location." So Bill (and others), have the lovely people at www.digitaltelevision.gov.uk told you which frequencies will be used in each location after switchover? Or are you as in the dark as the rest of us, meaning that "An appropriately qualified local installer" will have no better idea of what aerial might be best after 2012 than anyone else reading uk.t.d-tv? Cheers, David. |
wrote in message oups.com... wrote: I was reading this document... http://www.digitaltelevision.gov.uk/...odpractice.pdf [snip] Ah, now I've got to page 23 (21 in print), I've found... "As a result of digital switchover, most current DTT transmissions will need to change channel. Public service channels will generally move into channels formerly used by analogue services, though there will be some local exceptions. But at most locations, some new frequencies will be brought into use for digital TV services. At present, the proposed allocation of channels after switchover is still subject to change and will become clearer for installers in 2006. "Most IRS and MATV systems contain signal processing equipment that is tailored to the channels currently in use in a particular area. Therefore, where new channels are brought into use at switchover, it is likely that changes to the equipment will be required, involving a visit to each MATV or IRS head-end. "It is clearly helpful for the system designer to account for any changes in frequencies b e f o re switchover - ideally before installation. However, as information about new channels will not be available for some time, installers should, for the time being, offer flexibility to allow for modification of upgraded head-ends at some point before switchover." In other words, we're starting this switch over malarky in 3 years, but we still haven't figured out what frequencies will be used, so it's not possible to install a communal system now which won't need some further work in 3-6 years time - unless no channel filters are used in the system. How nice of the government to drop these costs onto people. Not only the cost of "going digital" itself, but the extra cost of a second call-out at the time of the switch over. It sounds like the very worst project management: start the job without defining what the final deliverable should be. 6 years after the launch of DTT, and only 3 years before analogue switch off in the first region, they're still saying "we'll give you full details next year". Am I the only one that thinks this sounds like a bad joke? Seems like good advice. It looks like it hasn't been possible to check out all possible permutations yet, but come the switchover the main channels will be in the same band as they are at the moment. Therefore those who haven't upgraded will still be served with the same channels they have had pre-switchover and, most likely will be able to receive several if not all of the extra channels. Those who cannot receive all the extra channels will need an aerial upgrade to receive them. If you upgrade now then fit a wideband aerial - no change in the advice then. I'd say that 2 years notice for the border region was plenty for the manufactures & installers to get their act together. -- Paul Schofield |
Paul Schofield wrote:
wrote in message [snip] Am I the only one that thinks this sounds like a bad joke? Seems like good advice. It looks like it hasn't been possible to check out all possible permutations yet, but come the switchover the main channels will be in the same band as they are at the moment. Therefore those who haven't upgraded will still be served with the same channels they have had pre-switchover and, most likely will be able to receive several if not all of the extra channels. Those who cannot receive all the extra channels will need an aerial upgrade to receive them. If you upgrade now then fit a wideband aerial - no change in the advice then. I'd say that 2 years notice for the border region was plenty for the manufactures & installers to get their act together. I don't agree with your advice Paul - there are plenty people for who fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Anyway, the advice I quoted isn't for "normal" houses - this is for communal aerial systems, serving several (or even several hundred) outlets. These normally have channel filters at the input, and sometimes channel transposers, diplexers etc. Some of these things are fully tuneable, some are only tuneable over a limited range, and some are fixed. The document suggests that "most" areas will see the PSB muxes moved into the existing analogue frequencies, but some areas won't, and the "non-PSB" muxes may use different frequencies in most areas. That suggests a filter system set up for analogue and digital now would give 0, 2 or 3 muxes out of 6 come switch over. Depending on the choice of filter, switch over may require some retuning or replacement. If you've lived in rented accommodation, then you might know that there are communal aerial systems out there that have been in use for 30 years, and haven't seen any maintenance during that time! Yet there could be high quality systems installed in the last five years which are going to deliver half the channels at best, and zero channels at worst come switch over, despite delivering all analogue and digital services now. This will be news to many people! Yet it's impossible to say which systems will be affected because the frequency allocation information still isn't available. I think the "final" frequency allocation should have been published during digital switch on, not analogue switch off! Then people installing systems for the past 6 years could, if they'd wished, have made provision. I'll tell you what though - I think I'm going to become Bill Wright's apprentice, because he's going to be in a very good business from 2008-2012! Especially 2011, if the region-by-region switch off dates are to be believed. Cheers, David. |
wrote in message oups.com... Paul Schofield wrote: wrote in message [snip] and some I don't agree with your advice Paul - there are plenty people for who fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Not doubting the statement, but can you explain why that's the case for CP Anyway, the advice I quoted isn't for "normal" houses - this is for communal aerial systems, serving several (or even several hundred) outlets. sorry - note to myself - read the post carefully -- Paul Schofield |
I don't agree with your advice Paul - there are plenty people for who
fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Why single out CP? Asks a man about to replace an aging TV aerial and planning on using a wideband one :-) Paul DS |
Paul D.Smith wrote:
I don't agree with your advice Paul - there are plenty people for who fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Why single out CP? Asks a man about to replace an aging TV aerial and planning on using a wideband one :-) I'll put money on my prediction that after 2012 every Mux from Crystal Palace will still be in UHF Group A. As for the rest of us outside the M25, gawld only knows ! -- Mark Please replace invalid and invalid with gmx and net to reply. |
Paul D.Smith wrote:
I don't agree with your advice Paul - there are plenty people for who fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Why single out CP? Asks a man about to replace an aging TV aerial and planning on using a wideband one :-) Paul (and the other Paul), because all the transmissions from Crystal Palace are in group A... http://www.dtg.org.uk/retailer/tx_lse.html As you can see from that website, there are many many transmitters where the official advice is still to use something _other_ than a wideband aerial for receiving analogue and digital. That advice is unlikely to change post switch off (though exact frequencies may, hence my original question). The aerial grouping may remain correct even if further services launch after switch off. There is some relevance, even to simple domestic installations - there must be people who receive adequate analogue reception through a reasonably high gain grouped aerial. They could swap to a wideband aerial now and receive poor analogue and digital reception, or they could wait until switch over, save a few quid, and receive adequate digital reception through their existing grouped aerial. There must be at least some people in this situation, but they (and we - the "informed" techies) don't know because the information hasn't been made available. Maybe the CAI want to hide this fact from the public: that many folks need do nothing to their aerials, and come switch over, digital will just magically work for them. Far better to tell everyone that they must get a DIGITAL aerial now otherwise they will lose TV at switch over. Sounds like a great scam if you ask me! Cheers, David. |
wrote in message oups.com... Paul D.Smith wrote: I don't agree with your advice Paul - there are plenty people for who fitting a wideband aerial would be the worst thing to do - the ~8 million served by crystal palace for a start! There are many other places where a grouped aerial is still the best bet (if not downright essential!) - in these regions it would be very valuable to know what's coming after switch off. Why single out CP? Asks a man about to replace an aging TV aerial and planning on using a wideband one :-) Paul (and the other Paul), because all the transmissions from Crystal Palace are in group A... Okay I can see that you don't need to have a wideband aerial to receive analogue or digital signals from CP, but is there a reason why you shouldn't use a wideband aerial? In any case this is not due for another 7 years for this region so hardly a desperate hurry. -- Paul Schofield |
There is some relevance, even to simple domestic installations - there must be people who receive adequate analogue reception through a reasonably high gain grouped aerial. As one of them may I seek advice? I need to replace the current (25 year old) aerial/cable in order to get a decent digital signal from CP. (Analogue is fine; and Telewest cable means no pressing need.) CP is just 14.5 km away. So my initial reading suggested a simple Group A (e.g. XG8) would do fine. But then I see nearly all the neighbours with new kit have wideband aerials - some of enormous size. There is some risk of blockage/ghosting from a hospital near the line of sight. But I've been on the roof and it isn't that near. So I guess it's insurance against change. So what do I do: go wideband and get a worse signal now? Go wideband and risk a poor signal now? Go wideband but with a bigger aerial (at greater cost - and some risk to the Victorian terrace's chimney)? I have yet to find the compliance cost assessment/regulatory impact assessment in which such costs are appraised. Anyone have a link please? Robin |
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