The ABC states in the promotional blurb for the Ultimo studios that they are HD capable, so it’s a pity that doesn’t extend to the news studios.
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That’s bad enough, but given that they could at least make the set, background and angles look as good as possible. The background photo had lots of sharp lines and contrast and looked shocking. They need a soft image there, and cut out the wide shot as much as possible.
From what I can gather, standard definition FTA TV in the UK operates on MPEG-2 DVB-T (70 channels in total), while all high definition channels (of which there are 15) operate on MPEG-2 DVB-T2.
How would we go spectrum-wise if we put current and future HD multichannels to MPEG-4 DVB-T2, but kept the current SD channels as they are (and maybe HD primary channels to show viewers what they’re missing out on). How much spectrum does DVB-T2 use versus DVB-T and what are the other benefits?
It would be nice if this type of compatibility was mandated in advance, so that down the track, when (or if) the change happens, we could have less viewers with problems.
HD channels in the UK use MPEG-4 DVB-T2.
The way it works is:
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The BBC has 2 multiplexes - one which carries BBC SD channels with DVB-T, and one which carries BBC HD channels with DVB-T2.
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ITV owns 1 multiplex outright, and another which is shared with Channel 4
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Arqiva (UK equivalent to ACMA) owns 4 multiplexes, two of which are used to transmit a mix of commercial SD and HD channels with DVB-T2 (ITV HD and C4 HD channels are broadcast on these multiplexes).
The HD multiplexes are transmitted using the 256-QAM encoding system, allowing a 40Mbit/s data rate. DVB-T only allows for 64-QAM encoding so it’s limited to 24Mbit/s. So effectively more data can be squeezed in the same 7MHz bandwidth as DVB-T.
The rule of thumb is that the higher the QAM, the more data you can transmit. The big problem being that the signal is far more susceptible to interference. However, DVB-T2 was designed with improved reception in mind so that shouldn’t be too much of an issue.
With the closure of Channel 31 in most cities, I reckon the leftover frequency should be used for multichannel SD or HD services (each broadcaster being given an allotment). With new HEVC encoding coming onto the market, you can fit 6 1080p50 HD channels onto that same amount of spectrum (which is what is being done in Germany).
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Arqiva (UK equivalent to ACMA) owns 4 multiplexes, two of which are used to transmit a mix of commercial SD and HD channels with DVB-T2 (ITV HD and C4 HD channels are broadcast on these multiplexes).
Nope, the HD service of ITV, C4 and C5 are on the BBC’s DVB-T2 MUX (that one is called BBC B, the SD one is BBC A), which also carries CBBC HD and Film4+1 (in SD MPEG-4).
BBC News HD and BBC Four HD (which is time sharing with CBeebies HD) are on COM7. Reason for that is that COM7 and COM8 weren’t existing when ITV and C4 wanted to start in HD and the BBC had a whole lot of unused space on their MUX, so the rented the vacant space to the others. And at the moment COM7 isn’t broadcasting to all of the UK, so it is staying like this till they go HD only so all viewers have access to at least the main channels in HD.
By the way, here is the listing as of today:
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In comparison to how many SD channels on DVB-T2? Actually, can you also compare max number of MPEG-2 SD channels versus max number of both MPEG-2 SD channels (for more even visual comparison) then the max number of MPEG-4 or HVEC HD channels? Thank you so much for explaining this.
The UK uses 8 MHz channels. Australia uses 7 MHz.
They’d better do something soon with the spare UHF channels in metro areas. Already noticing a lot of new VHF only antenna installations. Those people won’t be able to properly receive any new offerings on UHF in the future. And they sure won’t want to spend money to upgrade their antennas again!
ACMA needs to get on the case… now!
Amazing they have so many channels available on FTA, and can fit them all in!
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There aren’t meant to be any. Once the community channels go off all 5 networks plus 1 spare will all be VHF from the main site. No plan for UHF from these towers unless the government can be persuaded not to shut down community TV.
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It’s because they use 480-700MHz, which is used mostly by Digital Two Way Systems like DMR.
Arqiva is nothing like the ACMA, it runs like BA (Broadcast Australia)
The UK has OFCOM as their regulator.
Whilst I was capping in the UK, I noticed that the ITV multiplex had better strength then BBC A / B
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Part of it is that you don’t ever get the full amount of channels all the time.
For example, in Australia you have ABC Kids and ABC2 treated as different channels, but they share a channel number and the channel is named awkwardly to try and indicate that.
In the UK, CBeebies and BBC Four share the same channel space - however they use different LCNs, so have a totally split program guide. That way if you leave the TV on CBeebies and it hits 7pm, you’d just get a placeholder screen after then, rather than it becoming BBC Four.
If you sort the Wikipedia page by the Broadcast Hours column, you can see the extent of this.
In addition, they run a lot of channels at very low bit rates at lower than SD resolution - just to squeeze more in. And there’s a shitload of shopping channels, and timeshifts.
It’s the UK’s regulation more than any technological difference that creates what they have in their market - a company can just buy a timeslot on the multiplex and launch a channel with enough money, leading to a diversity of operators and formats.
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That was one of the reason for restacking the channels in a group together – so that people would only need an antenna for a smaller range of frequencies so that less sensitive broadband aerials wouldn’t be needed.
Each transmitter location is allocated six channels – five for the existing broadcasters and one ‘spare’. The spare channel is in the same group as the other channels. For example, Sydney has VHF 6, 7, 8, 11 and 12 for the existing broadcasters and the spare is VHF-10. There won’t be any new services on UHF.
As opposed to more multiplexes in the future, the government actually wants to go the other way – i.e. switching to more efficient transmission standards/codecs to reduce the amount of multiplexes allowing them to have another ‘digital dividend’ and sell off more spectrum to telcos.
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I know that. But there will be the spare high powered channels on UHF that have been used by SBS and community TV. These could easily be used for more digital multiplexes in the future. Whether experimenting with new technologies or allowing current broadcasters more bandwidth.
I doubt there would be many spare frequencies available; for example in the Brisbane area, Channel 28 is marked as the 6th network unallocated channel for the SE suburbs plus the Darling Downs and Ch 36 that was used by SBS is allocated as the 6th channel for Southern Sunshine Coast, so in effect the only free channel for Brisbane is the unallocated channel 10.
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I remember reading that ABC1 in the UK (an offshoot of the American ABC) only had something like 2 or 3 hours allocated to its timeshare.
Same with the ill-fated ITV News Channel, which I recall having to timeshare with one of ITV’s digital multichannels toward the end of its life - not very appropriate for a supposed 24-hour news channel!
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And those UHF spares are linked to the VHF spares in that Brisbane example
ie. whoever gets VHF 10 up on Mt Coot-tha will get UHF 28 for the Brisbane SE repeater.
Fair enough for Brisbane. What about the other metro areas where repeaters (actually translators) exist but there’s no pressure to use any of the leftover/spare UHF channels?
Sydney’s the same as Brisbane; all five allocations are in use:
Block A (VHF 6–12): Main Sydney transmitters + digital radio
Block B (UHF 28–33): Sydney UHF translators (SFN for Kings Cross, Manly, Kurrajong, Picton, etc.)
Block C (UHF 34–39): Main Illawarra transmitters (which in some parts of Sydney come in better than the local Sydney signals)
Block D (UHF 40–45): Central Coast SFN (which gets into the Northern Beaches of Sydney) and more Sydney UHF translators (Campbelltown, Woronora, etc.)
Block E (UHF 46–51): Central Coast SFN overflow
The Central Coast uses up two blocks due to the transmission of both Newcastle and Sydney stations.
Block E, generally, (and UHF-51 in particular) is not supposed to be used for high-powered transmissions due to its proximity to the LTE mobile signals, so it wouldn’t be suitable to put new metro-wide channels there in any case – not to mention most Sydney households don’t have antennas for Band V UHF channels (SBS and community TV used to be on Band IV). The only unused allocation is the ‘spare’ channel in each block.
The community stations were operating out of their designated block. For example, TVS in Sydney was operating on the ‘spare’ channel on Block B when it should have been in Block A. I assume if community TV does somehow get resurrected it would either be moved to be in the correct block (on the ‘spare’ channel) or just tacked onto one of the other multiplexes such as SBS or ABC.
If there are to be new services, I assume that it would be rolled out to all five capital cities; given that at least two out of the five capital cities don’t have any free channels available, it’s not going to happen on anything other than the ‘spare’ VHF channel.
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Thanks tvcl for that very comprehensive rundown of what’s happening in the Sydney area.
Very interesting!
Another way that they’re getting channels on the Freeview UK platform is via HbbTV (same as Freeview Plus here). As far as I know, Vision 247, which is channel 244, uses HbbTV to deliver 29 channels on their single channel. Of course, this limits viewers to those with compatible smart TVs and decent Internet connections, but this does open up a lot more content for viewers without being limited to the bandwidth available in a multiplex.