All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
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.
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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.
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Nobby: How long ago did you lose them? Both services have moved to the newer Astra 2F satellite in the last couple of months. This satellite has a tighter footprint than Astra 1N - which was not originally intended to serve the UK channels, but was moved to this position temporarily to allow the original Astra 2D satellite to be decommissioned early - and so less signal is available in Menorca.
You may be able to recover reception with a larger dish, but you should be aware that the broadcasters are deliberately trying to prevent you receiving the channels. They would have to pay more for content if they were to broadcast Europe-wide than they do if they constrain their broadcasts to the British Isles only. They have to be seen to be making their best efforts to restrict coverage.
The BBC will be moving their services later in 2013, when Astra 2E launches. It is expected to have a similar footprint to Astra 2F.
See BBC - Blogs - About the BBC - Changes to BBC satellite transponders in 2013 and BBC & Sky satellite TV installation in Madrid, Spain .
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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.
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Val: No. This was a deliberate ploy to get you to subscribe to Sky's satellite service, or to their on-demand service, Sky Go.
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.
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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.
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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.
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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.
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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.
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Monday 14 January 2013 5:47PM
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.