All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Arthur Morley: There are suggestions that the true coverage is substantially wider than that footprint plot suggests. However, I wouldn't depend on that. SES have just launched the Astra 2F satellite, which is designed to operate at 28.2°E, unlike 1N whose permanent home is at 19.2°E. This carries a rather tighter UK spot beam: https://sat.ses.com/webservice/images/12494500 . Also, SES have published the footprints straight away, whereas for 1N the footprint was only published months after it went up, after a lot of testing and calibration.
They haven't said so explicitly, but my expectation is that 2F will take over from 1N some time early next year, just as 1F took services from 2D. The press release about 2F's launch says:
'It is the first of a three satellite investment programme (ASTRA 2E, 2F and 2G), that provides replacement and growth capacity for the UK and Ireland at the 28.2/28.5 degrees East neighbourhood.
'"ASTRA 2F will provide seamless replacement capacity for our UK customers like BSkyB, the BBC, ITV, Channel 4 and Channel 5, and will allow us to operate additional capacity at 28.2/28.5 degrees East on SES satellites. [...]"'
- 
News - SES.com
M
PICK TVThursday 11 October 2012 3:53PM
Generally this site is for asking for help with reception issues, rather than commenting about programmes.Ian: Same reason as for switchover. The transmitter groups are more than somewhat interdependent - many changes are transmitters moving from channels that are not being cleared, to allow other transmitters a clear space to move into. Arqiva want to avoid having to recruit and train a large number of engineers for a single one-off event. Digital UK want to keep the volume of support calls down to a manageable level. MEM: I'm afraid Digital UK's postcode checker only shows good coverage for the PSB multiplexes for you, from either the Newry North, Newry South or Camlough transmitters. The PSB service from Divis is shown as good, but lower probabilities than from the other transmitters. Of the COM services, SDN and ArqA are shown as poor and ArqB no prediction is given.
A Group A aerial pointing at Divis is likely to give better results than a wideband; widebands have significantly poorer performance at low frequencies than a grouped aerial. Still, even the largest Group A aerial is unlikely to provide reliable service for the COM muxes.
Saorview's coverage checker for Quayside Close, Newry indicates that the best coverage for RTÉ services would be from Clermont Carn on C52, nearly due south from you, using vertical polarization. That is a different direction from all the other transmitters (to your north, north-east or west), and a different aerial group and polarization compared to Divis. You'd need a separate aerial if you want RTÉ. Frankie T: Unfortunately the 'HD TV' logo was defined by a Europe-wide body a few years before the UK regulator and broadcasters decided how we would transmit HD. The 'HD TV' logo only requires support for MPEG-4 AVC video transmitted in DVB-T multiplexes. The UK HD services use the newer DVB-T2 standard. It's quite likely that your TV doesn't support it. Look for the 'Freeview HD' logo or check for DVB-T2 support in the manual.
Transmissions in the Republic of Ireland use the MPEG-4 AVC standard in DVB-T multiplexes, so your TV can pick them up. RTÉ transmitted from UK transmitters, the 'Northern Ireland Mini-Mux' or NIMM, uses DVB-T2. SC: It's not guaranteed to work. If you would be receiving RTÉ from a transmitter in the Republic (Saorview), then MPEG-4 AVC support is all you need. If you received RTÉ on analogue, in reasonable quality, you will probably be able to receive Saorview.
The CAM should work as long as the TV sends any service, or any service that it can't decode, to the CAM slot. I believe some send only services that are actually marked as encrypted (decrypting services is the purpose of the CAM slot) which the Saorview services are not. The only way to tell is to try it.
However, if receiving from a Freeview transmitter, you will definitely need a Freeview HD box. The CAM relies on the TV being able to decode the multiplex, which yours won't be able to, as it does not support DVB-T2. The 'Northern Ireland Mini-Multiplex' uses the newer standard in order to get greater capacity from the available coverage than DVB-T is able to do. Richard: The Republic's transmissions into Northern Ireland are classed as overspill, which is normally treated as accidental. The only way this could be blocked from Northern Ireland is if it were also blocked from the Republic. The main transmitter spilling over into Northern Ireland is Clermont Carn, which serves a large part of the east coast of the Republic, particularly Dublin.
Considering that Saorview is estimated to be covering 60% of Northern Ireland's population, and the NIMM only 35%, it seems futile to be blocking the NIMM coverage. Simon Wynn: The HD channels have moved to 101-104 (plus 105 for S4C Clirlun in Wales) in order to put the General Entertainment section back together - it had ended up either side of the HD channels.
If the HD channels aren't there either, then we need your full postcode to offer more assistance. conor, leslie rainer: As always it is up to the broadcasters to decide when to start HD services, and when to leave Sky.
The Astra 1N satellite has plenty of capacity: it has 52 transponders but only 20 of them are in use, and there are spare frequencies not currently in use. SES, the operators of Astra satellites, are in dispute with Eutelsat over who can use which frequencies, but that covers frequencies *already* in use, broadcasting from Eutelsat 28A, rather than unused ones.
Each channel's broadcaster will have to decide whether the anticipated increase in revenue from going Free To Air will outweigh the loss of subscription revenue from Sky, any bribe that was made (e.g. subsidising their transmission cost on a Sky-leased transponder) and the costs of moving to a transponder on Astra 1N. There are also differences in Sky's charges for FTA channels versus for pay channels.
Freesat as an organisation is unlikely to have the funding from its parents, the BBC and ITV plc, to be able to lease a spare transponder and encourage individual channels to move over, without getting a transponder's worth of channels to do it in one go. It will probably take a whole broadcasting organisation, e.g. UKTV, to decide to jump. M
UTV HDMonday 29 October 2012 2:43PM
It is expected to launch on Freesat and Sky early next year (UTV's press release says 'first quarter').Nicholas Willmott: In some cases, because another transmitter will now be sharing those frequencies, or will be once a neighbouring group is changed. In others, because this group will be temporarily sharing until another group is changed (these may be temporary). Then there also seems to be a small group that is changing due to greater-than-anticipated interference from a station that isn't being changed. Some in west Wales may be down to greater-than-expected interference from Ireland - one of Ireland's transmitters had to change frequency due to greater-than-expected interference from Preseli.
In this batch, Trefin and Llwyn Onn get a power increase on C22/C25/C28, which aren't frequencies used in the clearance programme. They will be joined in two weeks by Waunfawr, Bethesda North and Morfa Nefyn. My guess is that probably the commercial muxes from Blaenplwyf are going further than they were supposed to, unless it signals an upcoming 3 dB increase of Blaenplwyf COMs, which are 6 dB down on the PSBs, rather than equal or only 3 dB down as at most other transmitters. The only other transmitters I'm aware of that have a larger-than-usual difference between PSB and COM power output are Brougher Mountain (10 dB down) and Belmont (complicated).
Similarly, the power increases on C41/C44/C47 at Ynys Pennal and Cwrtnewydd probably are to do with interference from Wenvoe, or maybe Arfon.
Briton Ferry has a *temporary* increase from 4W to 32W. It will change frequency (to C40), and return to 4W, when Wenvoe retunes, expected in March next year. (Wenvoe does not itself use C61 or C62, but has to release frequencies for Mendip, which does.). John Durrell: The difference in what your TV reports is *probably* down to using an external receiver rather than having the HD tuner built in to the set.
This is complicated by the fact that, on Freeview HD, the encoding hardware, and therefore the transmissions, can dynamically switch between 1080i50 and 1080p25 modes for every Group of Pictures (GoP). A GoP is a sequence of 15-25 pictures that are encoded using differences between the pictures, only one whole picture being sent in the set. The encoder switches mode based on how well the content compresses in each mode - if the source material was actually captured in progressive mode, or if there isn't much motion, it should compress better in progressive mode than interlaced. If there is fast motion, it will look better in interlaced mode.
It is never anything to do with your aerial - the decision of whether to choose i or p mode for a group of pictures is taken by the encoding and multiplexing hardware in London (and the BBC's backup location somewhere in the Midlands). For BBC One Northern Ireland HD, and UTV HD, a lightly-compressed high-bitrate signal is sent to the code-and-mux centre for compression and multiplexing. The resulting multiplex is sent back to Divis, where Service Information for the other multiplexes is added. It is then transmitted from Divis and carried via line feeds to Limavady and Brougher Mountain, which also transmit it. The other, relay, transmitters receive off-air from one of those three and retransmit. (Similarly, BBC One NI and BBC Two NI in standard definition are sent to the BBC's code-and-mux centres, while UTV and UTV+1 in SD are sent to ITV/C4 facilities elsewhere in London.)
The reason code-and-mux is done in England is simply that the majority of channels on most of the multiplexes only have one version for the whole UK, mostly played out or originated in London, and it makes more sense to bring in the few differences rather than send out the greater amount of content that is the same. Also, the same content is uplinked to satellites for satellite reception, where all the content for a single transponder has to be combined into one multiplex and uplinked from a single location.
The raw, uncompressed data rate for 1080p25 is the same as for 1080i50. 1080p25 means that 1080 lines are refreshed in full 25 times per second, taking 1/25th of a second, while 1080i50 means that half of the 1080 lines are refreshed in 1/50th of a second, followed by the other half in the next 1/50th of a second. In both modes, any specific line is only refreshed 25 times per second. 1080p50 doubles that to 50 times per second. Much equipment drops the '50' from the end of the indication and just reports 1080i or 1080p.
When a GoP is encoded progressively, the receiver can still send it on to the TV in interlaced mode: it just sends the lines in a different order to how it received them. There is no loss in picture quality and no difference in the apparent motion of the picture.
It may be possible to set up your receiver to send 1080p50 to the TV, if both support it. To receive the 'HD Ready' or 'HD TV' logos, and even the 'Full HD Ready' or 'Full HD TV' logos, the TV only has to support 1080i50 input - it does not have to support 1080p50. They only have to support 1080p50 in order to receive the 'HD Ready 1080p' or 'HD TV 1080p' logos. Sean Diamond: All YouView boxes meet the D-Book 7 requirements for HD and qualify for the Freeview+HD logo. It will therefore be able to pick up RTÉ whether you get that from a UK or a Republic of Ireland transmitter. Edwin Raymen: reception often does change over the course of the day, if it's marginal. (Either just above the signal-to-noise ratio required, or just below the point where too much intermodulation is occurring.) It's all to do with temperature and humidity, which affect how the signal travels, and also temperature of layers in the upper atmosphere, which in the right (wrong) conditions can bring in distant interfering stations.
Looking at Digital UK's prediction for the PE9 1DW postcode (which you put in the 'Your site' box) I see that there are three transmitters covering your area strongly, and two providing variable coverage. It may be that your equipment isn't tuning into the transmitter that the (presumably communal) aerial is pointing at. Many receivers just store the first services they find, when scanning from lowest to highest frequencies, which aren't necessarily the best quality versions. You could try retuning manually to see if you get better results from a different transmitter.
If you traditionally got ITV Central East/BBC East Midlands on analogue, your transmitter should be either Stamford or Waltham. If you got ITV Anglia/BBC Look East it should have been Sandy Heath, which is expected to give much better results than Tacolneston. There's a chance that you're now getting ITV Yorkshire East/BBC Yorks & Lincs from Belmont, which is predicted to be the worst option.
You could ask the aerial installer which transmitter the aerial is actually pointing at, and see if he can help you tune your equipment to the right frequencies. Alternatively, click the transmitter name links in the paragraph above to see the UHF channel numbers to try for each transmitter. Edwin Raymen: Do note that even if you're tuned into the correct transmitter, it could still be down to *too much* signal rather than too little. The three best transmitters all show 99-100% coverage for the three PSB services, and Waltham shows 96-99% for the COM muxes, while Sandy Heath's figures are over 85%. vicki: Well, there haven't been any changes at the transmitter and Digital UK's prediction suggests that you need barely any gain from the aerial, so my guess is that either a cable has become disconnected somewhere, or that the aerial has been damaged or moved, or possibly that water is getting in somewhere.
All outside cables should be well anchored down to stop them moving, and rubbing against tiles or brickwork. If they do rub, the insulation wears through, which allows water to get in. Water changes the way the cables work, massively increasing the signal loss in the cable.
You are very close to the transmitters, so it could be a case of receiving too much signal, though I can't see why the received signal level would have changed. If you have any amplification (boosters), try removing it or turning it down. If that doesn't help, and nothing apepars to be broken, try adding an attenuator. vicki: Additional thought - there was a retune event on the 31st, reorganizing the channel list. Did you retune? If so, it's possible that your equipment has stored a different transmitter from the best one available. Try doing a manual retune using Mendip's frequencies (if you had Freeview before switchover), which are: C61, C54, C48, C56 and C52 (and also C58 if you have HD).
You might find a better version of the services at a different place in the channel list, usually around 800 or so. If so, check which UHF channel/frequency those services are using, and retune manually using those frequencies.
Signal levels do vary over time, with changes in the weather conditions. It's possible that when you retuned, conditions were *just* good enough to detect the other transmitter and store the services. TV equipment should really check the quality and strength of each transmitter before deciding which version to store, and newer equipment (most Freeview HD boxes) does. Older equipment just stores the first version found when scanning from lowest to highest frequencies. Another factor is that all high-power sites have to be negotiated with our neighbours, due to the mutual interference. Signals can travel a surprisingly long way, for example Mendip had to be cleared with both Ireland and France.
The question is whether these 20 sites will be subject to a new round of negotiations, or whether the plan is simply to use the allocations we already have. If the latter, it could lead to some very weird results as to who gets what, with some low-coverage transmitters appearing and some high-coverage ones not. There's not even a guarantee that all sites will get both multiplexes.
Checking the sites with two allocations in the 31-37 range in the Geneva 2006 plan, I get this list, in descending order of 6MUX population coverage:
Crystal Palace
Belmont
Bilsdale
Rowridge
The Wrekin
Sudbury
Craigkelly
Divis
Ridge Hill
Lark Stoke/Bromsgrove/The Wrekin (SFN)
Stockland Hill
Caradon Hill
Darvel
Nottingham
Kilvey Hill
Tunbridge Wells
Fenton
Caldbeck
Lancaster
Pendle Forest
Rumster Forest
Hastings
Brougher Mountain
Eitshal
Blaenplwyf
Torosay
Bressay
27 sites, sum of gross 3PSB coverage 17,862,000 households, sum of gross 6MUX coverage 13,361,000 households. Top 20 give PSB coverage of 17,749,000 households and 6MUX of 13,277,000 households. The TV population is usually given as 24.8 million households, so assuming PSB coverage levels (which they should be, as the band is clear!) you get 71% population coverage, or 53.5% for 6MUX coverage levels.
Those with one allocation:
Sutton Coldfield
Emley Moor
Black Hill
Mendip
Sandy Heath
Waltham
Wenvoe
Moel Y Parc
Sheffield
Durris
Chatton
Whitehawk Hill
Redruth
Storeton
Guildford
Chesterfield
Saddleworth
Presely
Knockmore
Many other sites have additional unused allocations outside this band - we negotiated 8 'layers' per site for mainland UK and Northern Ireland. In many cases those allocations have had to go to neighbouring sites, where a site wouldn't have had six multiplexes after the 800 MHz allocations were removed, or have had relays carved out of them. Still, there *could* be scope for putting one of the multiplexes somewhere else, or borrowing a neighbouring allocation *from* a high-power relay that isn't one of the 6MUX sites (though it would inevitably be at lower power, to stay within the envelope of the original allocation). For a concrete example of that, see how Sheffield has borrowed C39 from Emley Moor.
There are of course massive omissions from this plan, particularly Winter Hill, Sutton Coldfield, Emley Moor and Black Hill. Some negotiation is likely to be required! It's far easier for Sky's 'barker' channels to convert a Freesat user to a Sky subscriber, than a Freeview user to a Sky subscriber. In the former case, they just have to get the customer to plug in a Sky box to the existing cabling. In the latter, they have to get the customer to get all-new dish and cabling installed. That's been a stumbling block for them.
It may be that they see Freeview -> Freesat -> Sky as an easier upgrade than directly Freeview to Sky, but that the absence of their channels from Freesat puts Freeview viewers off choosing that.
It is an interesting change in dynamic, now that switchover is complete: no longer are they trying to grab a greater share of analogue viewers, they're now truly head-to-head with each other. I don't expect there will be much all-new content on these multiplexes. I expect them to carry more HD simulcasts of existing services, probably services that are already available in HD on satellite, though the BBC's service(s) will be new. Just to clarify, when I said 'new', I meant that it would be HD simulcasts of existing BBC channels: just not ones that are currently broadcast in HD. There is no chance whatever in this climate that the BBC Trust and DCMS would approve an entirely new service.
David: That story dates from the end of 2010, just after the real-terms cut in funding and additional mandatory spending were announced, when the BBC had not announced how they planned to deal with it. Now they have. BBC Three and Four will remain, but "play supporting roles to the two bigger channels", BBC Three being aligned with BBC One, and Four with Two. 
BBC - Inside the BBC - Delivering Quality First
BBC HD's replacement by BBC Two HD is in order to save the, actually quite small, cost of its separate scheduling, continuity, branding and playout. This is around £2.8m per year. It's almost an accounting trick actually, because all the necessary HD infrastructure for BBC Two will then be divided among BBC Two's much higher viewer base and result in a lower cost per viewer hour, the standard that the BBC use to assess value for money. Mike: You say 'accommodation'. Is this a shared dish? If so, you should contact your landlord, agent or residents' association, whoever manages the property. My guess is that there is a fault on the multiswitch. Can your neighbours get the free channels on satellite? If so, it's likely just a fault on your link, but if others are having problems it's probably a problem with the low-frequency output on the LNB.
You should be aware that you CANNOT split a satellite feed, to feed more than one input or more than one box. Each input sends control signals to the LNB or multiswitch, to select the frequency range (LO or HI) and the polarization (H or V). If you split a feed, clashing control signals can be sent to the LNB/switch and you get unexpected results. The exact behaviour depends on what each signal is controlling.
If you only have one feed into your accommodation, you should plug that into the LNB1 input, and leave the LNB2 input disconnected. This does mean you can only record a programme and watch another, or record two programmes, when the programmes are on channels with the same frequency range and polarization (both LO or both HI range, and both H or both V polarization). michael: The BBC are reserved space for each local radio station covered by each local multiplex. They must wait for the commercial operators to launch their multiplex, and to extend service by adding new transmitters. The law doesn't actually say that the BBC is not allowed to bid, nor does the Royal Charter, but practically speaking, there are already licensees for all of the areas that the ITC and, subsequently, Ofcom have chosen to offer. The problem is that they haven't launched, and those that have launched haven't matched coverage. This is despite the Broadcasting Act 1996 section 49(1):
"In exercising their powers to grant local radio multiplex licences, the Authority shall reserve to the BBC such digital capacity as the Authority consider appropriate in all the circumstances with a view to enabling every BBC local radio service and every BBC radio service for Wales, Scotland or Northern Ireland to be received in digital form within a coverage area which, so far as reasonably practicable, corresponds with the coverage area for that service as provided otherwise than in digital form."
The operative words there are probably 'reasonably practicable'. The multiplex operators simply don't want to spend any more money than they are compelled to, as long as there is enough ad revenue coming in (same problem, of course, as the commercial TV multiplexes). The BBC has no power to require extension of coverage and won't want to - possibly isn't allowed to - fund an extension from which the commercial services will benefit.
The government will have to accept that to achieve a radio switchover, they must *require* the multiplexes to extend their coverage. Until they introduce that mandate, and probably offer some funding, it won't happen.
There is no great social benefit to a digital radio switchover - the FM band isn't really crowded enough to stop new community radio stations launching, and there is no other practical purpose for that radio spectrum. M
ITV HDWednesday 19 December 2012 12:25PM
Because the mode switches depend on the content transmitted, they will occur apparently at random, even within a programme, and different channels will be affected at different times.David Penfold: The Ofcom Radio Tech Parameters spreadsheet only lists Farthinghoe and Beckley (Oxford) at present. The legal requirement is only what they outlined in their Technical Plan when they applied for the licence: Beckley, Boars Hill and Oxford. 
Ofcom | Radio Multiplex Licence Award: Oxfordshire
Only five years late launching...
The Arqiva document that Briantist referred to was created for Ofcom's DSO consultation titled "An approach to DAB coverage planning". In the post-consultation Interim Statement, Ofcom said:
"The options we proposed do not constitute a definitive or final view on any post-switchover DAB network but will inform the Governments decision about whether to proceed with digital radio switchover. We noted that further technical work on network planning, and public policy decisions by Government on the issues raised, would be necessary."
No-one has yet figured out who is to pay for increasing the DAB coverage to the same level as FM. The commercial stations don't want to do it as additional coverage comes at an ever-increasing cost per additional listener, typically less than the additional fees that could be charged for advertising. The multiplex operators will only do it if their customers ask, and pay, for it. The BBC can't afford it and currently isn't required to do it (for local radio; for national radio the current licence fee settlement requires them to get to 97% population coverage, still short of the 99% FM is estimated to reach). Peter Dolman: Wenvoe is moving in part to get out of the way of Mendip (but also some of its own relays). Mendip will retune on 27 March: the BBC A multiplex currently on C61 will move to C49.
The two transmitters will not use interleaved frequencies after this retune, but Wenvoe will stop at C47 and Mendip will start at C48, making the 'remove the aerial cable' technique effectively impossible anyway. Vodafone, O2 and EE have all received permission to convert some of their 2G allocations to 3G in the past, O2 certainly have done so in places.
Base stations are certainly not 'low power'. The permitted maximum power for 2G base stations is 32 dBW or 1.58 kW, for 3G that goes up to 35 dBW or 3.16 kW (at least that's true of the base stations at the Caversham phone exchange, over the road from me and on the path from me to the Hannington TV transmitter - though my aerial points to Crystal Palace). That's greater than a very large number of the relay TV transmitters, though not close to most of the 'main' TV transmitters.
The issue is going to be the *relative* power of the base station's signal, relative to the strength of the TV transmitter's signal, the background noise, and the interference from other TV transmitters that's already present. Different equipment is likely to be affected by different levels of interference. It makes figuring out who will be affected very difficult.
800 MHz transmissions may travel further, but that's true for both the wanted and unwanted signals. To get coverage at any decent level of capacity, they will need to use a dense mesh of base stations just as they do now. In rural areas, where it isn't interference-limited, there may be some advantage: however, that's the *least* likely place for 4G to be deployed. As ever, they will deploy the services in densely-populated town and city centres first, to maximise the number of people they can cover for the minimum outlay. Of the six blocks, only two will have any coverage requirements at all (these two will be auctioned together).
The auction is six blocks of 2x5 MHz, not three blocks of 2x10 MHz, though as I said earlier blocks 5 and 6 are to be auctioned as one lot.
I still find it deeply ironic that the guard band between downlink and uplink frequencies is 11 MHz, but the guard band between the new and previous users of the band is only 1 MHz. Josh: The problem is that HD uses about 3x the capacity of an SD stream, effectively making it 3x as expensive to broadcast. ITV are doing better from an advertising perspective, but still not that well. The major regions - with the most ad revenue - are therefore prioritised over the smaller ones.
There is a small capacity boost by switching to DVB-S2 broadcast but you have to switch a whole transponder at once. It's also not recommended to dedicate a whole transponder to just regional variants of one service, as they will be broadcasting the same content a lot of the time; the statistical multiplexer will struggle as the demands will flex at the same time. (Small delays are introduced on the SD service to stop them being completely in sync!) Therefore they are likely to have to rent more than one new transponder to get additional regions on satellite. To make it cost-effective they'd have to find other channels wanting to lease part of the capacity, e.g. 10936V carries 'Star Plus UK' in addition to two ITV regions and one STV.
We may hate that the channels' decisions are based on the satellite platform first, but the fact is that satellite users tend to have more disposable income and are more attractive to advertisers. Since the number of satellite users on the main set is about the same as for terrestrial, the consideration tends to be satellite-led. Not to mention you can effectively get bribes from Sky, by arranging for Sky to lease the transponder, or otherwise subsidise the service. ITV 2, 3 and 4 HD are currently encrypted.
If they are doing it by ad revenue I think Yorkshire (West) would probably be the next to get an HD service: it was one of the first round of +1 services. Having said that, it might not be that soon as ITV have just paid a lot to get all of their regions onto the UK-footprint satellites and broadcast in the clear. This means Freesat viewers now have all four ITV HD services on satellite, not just London and Granada, as well as all ITV SD subregions and all the ITV +1 services that are broadcast. Sites were left off the list as there were no spare allocations for them. Simple as that. Allocations have been moved around between transmitter sites, to move them from sites that have lower population density to those that serve more households. The Wrekin's allocation of C33 and C35 has been given to Sutton Coldfield.
Ian: Waltham is on ths list, this list is sorted roughly in population coverage order and Waltham is #10 in UK households covered (gross coverage). The Scottish, Welsh and Northern Irish transmitters have been pushed up the list from their actual population coverage. (Wenvoe is actually #15, Craigkelly #18 and Divis #21, ranked by 6MUX coverage.)
I posted the list of usable allocations that the UK got at the Geneva conference in 2006, at Ten more HD channels on two new Freeview HD multiplexes on air from 2014-18 | Freeview news | ukfree.tv - 10 years of independent, free digital TV advice . As I said at the time, Winter Hill, Sutton Coldfield, Emley Moor and Black Hill didn't have enough, or even any, usable frequencies, so we've had to pull together a network out of what we did have, plus agreeing with neighbouring countries where we can modify the plans to avoid mutual interference.
Ofcom's spreadsheet at 
http://stakeholders.ofcom….xls is surprisingly illuminating as to what restrictions we've managed to negotiate. The permitted transmitter power is in the RPC_ERP column: it's either a figure in dB-watts (dBW, decibels relative to one watt) or a Reference Planning Configuration. For example, Ireland seem to have been OK with Black Hill using full power (50 dBW = 100 kW) in all directions, but Winter Hill, while being permitted 100kW in most directions, will have to have a 14 dB notch in the direction of Kippure.
However, in most cases we're not going to get anywhere near the negotiated ERP limits. The coverage figures are based on Arqiva's Reference Offer indication of what they can do with the spare transmitters they have after switchover - some old analogues, some pre-switchover digital - and with the antenna systems already on the masts/towers. In some cases the proposed power for 600 MHz is actually lower than pre-switchover levels (e.g. Oxford at 5.8 kW, where pre-switchover levels ranged from 6 to 10 kW). Also note that at many sites the two new multiplexes will broadcast at different power levels.
http://www.arqiva.com/cor….pdf
Some transmitters will be having a nice tour around the country: my favourites are the Croydon backup BBC One and Two analogue transmitters travelling up to Winter Hill, and Dover's to Emley Moor. Only Mendip and Sandy Heath are proposed to get new antennas. M
PICK TVMonday 11 February 2013 4:52PM
PICK TV is Sky's 'barker' channel. Its purpose is to try to push Sky subscriptions by dripping out bits of Sky's subscription schedules. That's why they don't show whole series or put in massive pauses between parts of a series.Dave, KMJ: Channel 5 withdrew due to "financial constraints". It is widely believed that those financial constraints include some incentive from Sky for the channel to remain exclusive to pay services. That may be as simple as Sky paying the carriage costs on satellite, since the satellite transponder is shared with Sky Sports News HD and ESPN America HD. It may be that Channel 5 thought they could renegotiate this contract or break it early, but found that the compensation to Sky was too high to be covered by the expected ad revenue from Freeview. Which, to be honest, is unlikely to be substantially greater than the current revenue, as many viewers will simply switch from watching C5 in SD to watching it in HD.
On top of that, Channel 5 SD services have regional advertising - there are five versions of Channel 5 SD on satellite for this reason.
If Channel 5 wanted the HD service to go free-to-air on satellite, they would first have to lease a transponder, or space on a transponder, that uses the UK spot beam (although the current transponder is on the Astra 1N satellite, it uses the pan-European beam). Channel 4 and the BBC have spare capacity on the transponders they use for their HD services at present.
That's not a pre-requisite for going on Freeview, of course: as others have said, the UKTV stable are on Freeview without subscription, but require a subscription on other platforms. Nedbod: As Dave Lindsay said. The increased bitrate comes at a cost: the required signal-to-noise ratio to nearly guarantee fully reliable reception increases, meaning that effectively coverage is reduced. The commercial operators can get away with this because they don't have to meet a high coverage target (their only requirement is to match pre-switchover Freeview coverage), while the PSBs have to achieve at least coverage matching analogue coverage levels.
The BBC take quality more seriously than the others, putting only seven video streams on PSB1 (with radio stations occupying enough space for an eighth), where ITV/C4 are aiming for nine on PSB2, and the commercial operators run 11 or 12. Two of the BBC streams - BBC Parliament and 301 (Red Button video) usually run in reduced resolution, in order to provide more capacity for the 'proper' channels. Brian:
1. Use Auto on the TV, and select 16:9 output on your receiver (e.g. Freeview box)
2. The signal strength of a SCART connection is sufficient to travel about 10 metres. If you're seeing noise on the picture, it's more likely to be because some other cable runs near enough to the SCART cable for the noise to be picked up. Fully-screened SCART cables should usually reject enough noise, though.
If you lose colour, it usually means that one or more of the pins in the cable isn't making proper contact. Unplug the cable and plug it back in, making sure it's fully pushed home. This may also fix your noise problem.
If any of the pins in the plug are pushed into the housing, or bent, replace the cable. They should all be the same length, and only slightly shorter than the outside housing.
There are also different modes for how colour information is sent down the cable. Make sure that if you have selected RGB mode on the DVD player or VCR, that the TV is configured to use RGB mode too. My parents' old Panasonic TV can only handle RGB signals on some of its SCART inputs, so check the manual.
The other mode that everything supports is Composite, which might also be described as CVBS.
One of the cable's pins allows the sending unit to say that it is sending composite mode or RGB mode, so it may not be necessary to select which mode the TV uses.
Rarely, equipment also supports S-Video, or Component. Don't select these options unless you're sure that both ends support it.
If your devices have two SCART sockets, make sure that if they are connected to each other, you have a set of chains (e.g. TV<->DVD<->VCR) and no loops. Jamie: The 'Channel 59' filter is actually a smaller cheaper one with a shallower roll-off. It only needs to pass channel 59 and below, so it can partly filter channel 60 (i.e. it can roll off across the 8 MHz of C60 plus the 1 MHz guard band). The 'Channel 60' filter has to be able to pass channel 60 and below, with a sharp cut-off (only having the 1 MHz guard band), so it's bigger and more expensive.
Given they're expecting to have to produce nearly a million of these, it's worth the extra design cost to have a cheaper version for the majority of households, in addition to the more expensive one that would work for everyone.
I suspect that Briantist has probably got the colours the wrong way round, and actually the green areas can have a 'Channel 59' filter, and only the red areas need a 'Channel 60'. The red area at the northern edge of the E postcode area is in the vicinity of the Chingford and Edmonton relays, where the BBC A multiplex broadcasts on C60. There's a small red patch near Woolwich as well. Jamie: Thinking about it, it looks like you assumed that these are notch filters that filter out the specified channel.
They are not. They are low-pass filters that pass everything up to and including the specified channel, and block the 4G signals from reaching your TV/receiver/amplifier. The Channel 60 filter has to be steep so that it eliminates as much as possible of any transmission in the 4G band, which starts at 791 MHz. C60 goes up to 790 MHz. Briantist: My assumption is that BBC Two HD will be the sustaining feed for BBC Two, just as BBC One HD is for BBC One. If they're going to run 3D experiments on BBC Two HD, the SD services will have to opt out, so they'll have to build some BBC Two England SD opting capability. (Assuming that they actually provide a different programme on BBC Two SD compared to BBC Two HD - if they simply playout a downscaled 2D version, that would be fine.)
They will also have to be very sure that whatever they do for 2D compatibility works properly on all HD equipment. I recall reading that for at least one 3D trial, there was an MHEG application that stretched the left-eye image over the whole screen, but that only gives a 960x1080 image which many viewers may not find acceptable.
If they can't reach agreement on that, it might be possible to use some spare capacity on the HD multiplex, and on one of the BBC's leased satellite transponders, if they haven't yet found a tenant. 303 is still in the Freeview EPG. I don't know if it's difficult to get an additional video stream turned on for Sky and Freesat, without requiring retuning. Briantist: BBC One still has an SD sustaining feed for the English regions, but it's not played out separately. It's a downscaled version of the BBC One England HD sustaining feed. (An interesting question is what happens if a region fails to opt for the local news: do they still get London regional programmes as before, or do they now get the 'This is BBC One HD' slide? That is, is the SD sustaining feed actually SD London, and the regions opt from that, or do the regions opt directly from the downscaled HD feed?)
I expect this to be the same for BBC Two, now: the BBC Two HD feed is the master playout, BBC Two sustaining feed is a downscaled version of that, and BBC Two Scotland, Wales and NI opt out of *that*. If, however, you're going to put 3D content on BBC Two HD, and it's not the same programme as scheduled for BBC Two England, you need some way to inject programmes into the SD feed, even if the nations then opt out of it.
Sounds like a whole heck of a lot of trouble for very rare occasions when a 3D trial programme is running. P Silverman: The masts are owned by Arqiva, the BBC no longer owns any of its own transmission infrastructure (it was sold off in around 1995).
The mast is, as far as I know, temporary. Arqiva recently applied for, and were granted, a variation of the planning permission under which they extended the permanent mast. That variation (number 2012/05959/PA) says they must remove the temporary mast and its access road by 28 February next year. In practice that means it will come down this summer.
Arqiva asked for the extension of time basically because Ofcom are threatening to reorganize the TV spectrum once again, which could mean further changes to the antennas on the permanent mast. The current plan for launching the interim multiplexes in the 600 MHz band does not require any changes, however. http://www.arqiva.com/cor….pdf ed: Freeview should really refer to the schedule of programmes as 'services' rather than 'channels'.
The system used for digital TV delivers between 24 and 40.8 megabits per second of capacity for an 8 MHz block of radio spectrum, which is what we mean when we say 'channel' here. The channels are numbered according to the lower and upper limits of the block of spectrum, from C21 at 470-478 MHz up to C69 at 854-862 MHz.
That amount of capacity, per radio channel, is far more than any one service needs, so a number of services are bundled together into a 'multiplex'. The multiplex alternately takes a block of data from each service so that each service has the same approximate rate of data arriving. Different services are compressed by different amounts, different broadcasters having made different trade-offs between capacity and quality.
There are three Public Service Broadcasting (PSB) multiplexes, transmitted from all 1100 transmitters in the British Isles. There are also three Commercial multiplexes transmitted from 80 of the largest sites (those covering the largest part of the population). The multiplexes and their content are listed at 
Multiplexes | ukfree.tv - 10 years of independent, free digital TV advice .
Also, many services actually share their capacity over the day. So, for example, the same capacity is used to broadcast CBeebies (6am - 7pm) and BBC Four (7pm to 6am, approx). Some of the commercial multiplexes have up to four different services time-sharing the same slot. ozzie: The purpose of Pick TV is to get you interested in a series that is otherwise exclusive to a Sky subscription channel, then take it away half-way through to encourage you to take out a subscription.
No doubt it will be repeated on Pick TV as another incentive to subscribe - eventually. Briantist: Note that by the current Meridian licence, ITV are allowed to run the Oxford/Hannington ('Meridian West') service as an opt-out from the Meridian South (Southampton) service. The Meridian licence requires 2 hours per week for the West and East sub-regions, on weekdays, out of 3 hours 45 per week for the region as a whole. I believe they do run it as an opt-out, but I haven't watched it in years, and you can't get to it on the web version of ITV Player. Vectra: The work on the transmitter was to move the BBC services from C61 to C49. This was done to get out of the way of 4G mobile phone services due to be launched later in the year.
Some of these PC adapters and software do not get the tuning information by scanning the airwaves, or from another service they have already picked up, as TVs, set-top boxes and PVRs do. They get them from a central database. It sounds like that database is incorrect, and needs to be updated, or that you need to refresh your local copy of that information.
Check the device's manual, or the manufacturer's support website, to see how to update that data, or how to edit it if the central database cannot be updated. 
15:50
BSkyB investigated over BT claim it…
DTG :: News :: BT names Gavin Patte…
Hall to unveil ‘radical’ plans …
Freeview boss pins future on new HD…
Freeview and 4G at 800 MHz in Londo…
Region Northern Ireland | Switchover Help Scheme . This may be Freesat if Freeview is not possible, or they should offer Freesat as an option for a small fee. 
UKSatelliteHelp.co.uk - Satellite Dish Alignment / Setup Calculator 2.0 to calculate the settings required. 
BBC & Sky satellite TV installation in Madrid, Spain . 
Fire crews tackle Bicester blaze - ITV News