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Rebuilding Freeview High Definition from 2019 onwards

There is a bit of a dip in the space available on Freeview HD for high definition channels once 5G mobile services start next year, but the capability will return.

Understanding the capacity on Freeview HD is very lego  Photograph: Shutterstock
Understanding the capacity on Freeview HD is very lego Photograph: Shutterstock
published on UK Free TV

As Freeview High Definition users in Cornwall already know, the number of TV channels being broadcast in the UK will be cut back in mid-2020  to make way for the fifth generation of mobile phone data services.

This is because the number of multiplexes being broadcast will be cut back to the original six.   The extra two were provided as a “interim service”.    A Freeview multiplex is a single broadcast of binary data that occupies a 8MHz frequency range.    In the UK each of these can carry 24.1, 27.1 or 40.2Mbps or of data.

Because older TV sets and set-top boxes can only work with 24.1 Mbps, it is only possible for the owners of the multiplexes to use the higher capacity modes when every home has switched to Freeview HD capable equipment.  This equipment is marked with “DVB-T2”.

As illustrated, the total bitrate (in a home that can receive all the multiplexes) will change over time.

Meet the multiplexes

Not all the multiplexes are the same:

  • only three are broadcast to the whole of the UK;
  • a different three are broadcast in the better DVB-T2 mode;
  • legally, only BBC channels may appear on BBCA
  • also, legally, only public service broadcast channels (ITV, C4, C5) can appear on D3&4
  • The HD mode multiplexes have more bits and use a more video efficient encoding system (MPEG-4)
  • The current license to broadcast have different end-dates

This can be summaries in this table.

Multiplex name

 

Expires

 

HD mode?

Coverage

Mode

Bitrate today

com7

 

21 June 2020

 

Yes

76%

6

40.2

com8

 

21 June 2020

 

Yes

76%

6

40.2

D3&4

 

15 November 2022

 

No

100%

3

24.1

ARQA

 

15 November 2026

 

No

90%

8

27.1

ARQB

 

15 November 2026

 

No

90%

8

27.1

SDN

 

15 November 2026

 

No

90%

8

27.1

BBCB

 

16 November 2026

 

Yes

100%

6

40.2

BBCA

 

31 December 2027

 

No

100%

3

24.1

Freeview requires about 2.2Mbps for a standard definition channels and three times that for a high definition one (6.7Mbps). 

 

The Freeview HD EPG problem

One problem for people with Freeview HD receivers will note is that HD channels are grouped together in the program guide, rather than appear as replacements for the standard definition channels as viewers expect.    This is because the six channels on the BBCB multiplex (BBC One, BBC Two, CBBC, ITV, Channel 4 and Channel 5) can only be seen on newer boxes, making channel number replacement impossible without breaking the oldest Freeview equipment.

Basically the UK-wide BBCA and D3&4 multiplexes can’t change mode until ALL homes can receive them.

 

 

The interim position

There is good news, however, for the SDN, ARQA and ARQB multiplexes.    They can switch modes to the high definition whenever they feel that it is commercially practical.   This might be at a lower level of Freeview HD box use, perhaps 80% or 90%.   

By switching to DVB-T2 mode, each of them can increase their capacity from 27.1 to 40.2Mbps and take advantage of MPEG4. 

So, of the 80Mbps lost when com7 and com8 close, half of that can be got back by SDN, ARQA and ARQB upgrading, which would be enough for an extra 6 full HD services.

 

 

The HD public service channels

This diagram explains what will happen to create space six more Freeview HD channels.

The gains for the BBC when everyone has a DVB-T2 receiver are larger.     It will:

  • No longer need half of the capacity on the BBCB multiplex (20.1Mbps) as it can move these channels to BBCA
  • Gain 16.1 Mbps on BBCA due to the mode change;
  • Gain 6.6 Mbps from not simulcasting three services in SD and HD
  • Use the “gained 22.1Mbps” Be able to supply all the BBC television channels in HD to all UK homes

For the D3&4 multiplex, the gains are similar:

  • No longer need the 20.1Mbps on BBCB, making it available for other UK-wide services.
  • Gain 16.1 Mbps on D3&4 due to the mode change;
  • Gain 6.6 Mbps from not simulcasting three services in SD and HD
  • Be able to broadcast ITV, C4 and C5 in HD to all UK homes

 

I hope that's as clear as possible!  Any qestions? 



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Comments
Sunday, 1 December 2019
B
Bob B.
3:53 PM

I've got an interesting problem and I'd appreciate any ideas on what's causing it.

I live in Derby, receiving signals from Sutton Coldfield and the Derby repeat transmitter.
I'm in a block of flats with a communal aerial system and I have a couple of PVRs which I use, a BT YouView+ box (a Humax T4000) and a Humax HDR-FOX-T2.
For some time now, I occasionally lose the BBC HD channels - I find out because the BT box drops the channels, but the Humax keeps them. A rescan finds them again - until this weekend. The COM7 and COM8 MUXs had both disappeared, but occasionally, the signal strength display would show something - but never for long enough to do a manual search. (At one point, the PBS3 MUX decided to have a rest, but it seems to be back now.)
There are no reported problems at either transmitter, and when I switched the TV on this morning (an LG U750V) I checked the signal strength and both MUXs were shown as 100%. So, I rescanned the BT box (yet again) and it didn't find them. The TV now said 0%!

I don't have access to another aerial, but I did set up another box in the bedroom where there's another aerial socket - and that was showing the same thing. But at least is told me that the TV signal amplifier/splitter I have for the main system wasn't causing the problem The amplifier is set at mimulus now because the communal aerial was fixed a few years ago and the signal strength for the channels are between 73 and 82% when I've looked.

I thought it might be more than a coincidence that it's the 2 highest frequency MUXs that are affected - even though they are due to move to make room for 5G next year.

So, if anyone has any ideas that could help, I'd be grateful.

link to this comment
Bob B.'s 7 posts GB
C
Chris.SE
sentiment_very_satisfiedPlatinum

9:15 PM

Bob B.:

Firstly, Sutton Coldfield was having Planned Maintenance last week with "Possible service interruptions" which is likely to be the reason that some muxes disappeared at some point.
Second, from what you've described I'd guess the BT box has a less sensitive tuner than the Humax.
Third, to clarify, COMs 7&8 are indeed the highest frequency channels C55&C56 at transmitters where they have finally moved to those SFN (Single Frequency Network) channels, but they are not due to move next year. See my recent post Black Hill (North Lanarkshire, Scotland) Full Freeview transmitter | free and easy for a bit more detail.

Reception of both Sutton Coldfield and Waltham transmitters can be quite variable depending on your location in Derby. This makes potential reception of the SFN channels quite tricky. We need a full postcode to check what the Freeview Detailed Coverage Checker is giving as predicted reception at your location.

There's another gentleman in Derby with similar issues with the SFNs and you may find the discussion on the Sutton Coldfield transmitter pages of interest.

link to this comment
Chris.SE's 2,543 posts GB
Monday, 2 December 2019
B
Bob B.
4:56 PM
Derby

Chris.SE:

Thanks for your help, Chris!
That may have been the case at times, but those 2 MUXs are still not being picked up by any of my equipment today, as well as the weekend.

The reason the BT box drops the channels is because it automatically updates its channel list, so channel changes appear automatically. The Humax only updates the list when it does an automatic search, but has the option to do a manual search on a single MUX.

I had found those pages when looking through everything I could think of and, obviously, they just told me everything was working OK at the moment...

My postcode is DE22 1GR. The BBC channels that are missing are not on the Derby transmitter, of course, so at least that's working!

I have picked up quite a lot about TV transmissions over the years, but I'm definitely not an expert, but having worked as a computer programmer for most of my life, I think I understand quite a lot about some parts of the whole network.
The reason I'm puzzled by this problem is that what I've done has shown my machines don't seem to be the problem, and the signal through the aerial socket isn't a problem because the other socket is the same, and there have been no reported faults on the transmitters. This does mean that I was suspecting the aerial, of course. Unfortunately, since it's a communal aerial, I know nothing about it.
There was a problem several years ago, and the engineer who visited, did find a problem (and also advised me to use rather better aerial leads, which I have) but he did say that it was the correct type of aerial. The only thing I can think of it to report the aerial to the flats management company, but none of the other channels are affected - the signal strengths do vary slightly of course, but they are all very similar to what they have been since his visit, and I don't see how a fault with the aerial could just affect those frequencies.
So, 'interesting' seems to be a good description of this problem.

Thanks again for your time - unless you can think of anything else, t looks like I need to report it.


link to this comment
Bob B.'s 7 posts GB
Tuesday, 3 December 2019
C
Chris.SE
sentiment_very_satisfiedPlatinum

1:42 AM

Bob B.:

Hi Bob, just to mention to start that Sutton Coldfield is on Planned Engineering again this week with "Possible service interruptions".
Well, according to the Freeview Detailed Coverage Checker, you shouldn't have any problems getting all multiplexes including the elusive COMs 7&8. The BBC RTIS Advice about receiving TV and radio | RTIS also predicts good reception of all muxes.
I don't know if you noted from one of my posts how to look at the predicted coverage but I might as well repeat it, it may be of use to any others reading -

Go to Freeview | All your favourite TV shows, all in one place and all for free scroll down the page to the box "Check Freeview at my home" and enter your postcode and house number/name. Scroll down the following page where available channels are shown in "tiles". Below the initial block there is a "down arrow" if not all are displayed. But if you are only interested in some channels click on that button on the top row. If you scroll down just after half way down the page, there is a button "Detailed view". If you click on that it will show the predicted reception of transmitters and multiplexes that may be receivable at your location.

If your communal distribution system is a "channelised" one, it's possible that the gain for C55 & C56 needs turning up a bit. Because of the way SFNs work, although there's been no change in the power at Sutton Coldfield, the received signal at your location may be less than it was as other transmitters have changed the COMs 7&8 to C55&C56.
Alternatively, the communal distribution system may have developed a fault, the aerial may have moved a bit or become damaged in recent bad weather etc.

However if, as I've understood it you also have a variable amplifier as part of your own distribution system, first switch it off and plug your Humax directly into the aerial socket and see whether you can get the COMs 7&8. That should confirm that your amp hasn't gone west, maybe losing gain at the top end or oscillating etc.! (I assume you've already checked all your coax connections and flyleads etc.).

Assuming all is ok with the amp, try tweaking it up a bit, watch the strength on the strongest UHF channels to make sure you don't overload any tuner front end - ie. strength going up and then dropping again as you are still turning amp gain up. Also of course watch for pixelation etc. Just because the strength may go into the 90's that's not necessarily a problem as things will vary from set to set (tuner to tuner), go by the results!

Whatever results you get, have a check with some of the others on the system to see if they are having similar issues. That would add strength to your case for getting the system checked over/repaired. Can't think of any other suggestions at present.

link to this comment
Chris.SE's 2,543 posts GB
B
Bob B.
10:13 AM

Chris.SE:

Thanks very much Chris.
I've seen the FreeView page quite often, but never noticed the 'Detailed View', so that was very useful for me!

Yes, it looks as if I should just report it and let someone else sort it out!
I have no idea what the system is like, but I'll mention your comments, and they can check (eventually).

I used the bedroom socket which doesn't have an amplifier and the result is the same, which rules out the amp. But just to make sure, I connected without the amp, and it is the same!

One thing you may be interested in it that the BT box (the UHD version, model DTRT4000) ideally wants a signal strength of 65%, and has problems if it's higher! I was told this by a BT Support person when I was having problems, and I thought that was very silly - I'd expect all the boxes to show 100% as the ideal level, and more than 100% if it's too high. However, I fitted an attenuator and it does make a difference!

Thanks very much for your help - it's been very informative!

link to this comment
Bob B.'s 7 posts GB
C
Chris.SE
sentiment_very_satisfiedPlatinum

2:45 PM

Bob B.:

Thanks for that bit of info about the DTRT4000. I've no personal experience with any Youview boxes, but as opinions and reviews about them are very mixed and quite a number of them seem to have deficiencies I just would not have expected (especially being made by Humax), I've no intention of buying one - unless I happen to see one being given away for a couple of quid then I might be tempted just to have a play with one!

Yes there are some sets/boxes where the "higher" signal levels seem to "upset" them, quite ridiculous IMHO, just shows what poor design the front ends are. Having attenuators handy is always a good idea, makes checking things out so much easier. Did you try turning your amp up for your set and/or T2 box just to see if it pulled them in?

Good luck with getting the communal system sorted! Let us know how you get on.

link to this comment
Chris.SE's 2,543 posts GB
B
Bob B.
4:17 PM

Chris.SE:

After several years of Humax models. I wasn't impressed with YouView - it was obviously developed on a fast network, so they decided to get the EPG data online when they wanted it. Of course with domestic broadband at the time, it was very slow. The YouView+ is better but I wasn't impressed at all. Then I became very impressed with it because I bought the latest (at the time) Humax which had Freeview Play and it was appalling, so I just had it as a spare machine,
That was the machine I used in the bedroom to check that signal, and I noticed there was a new version of the software, so I'll have to have to put it back onto my main system and see if it's improved.

Yes, I tried the top and bottom of the range., and some in between - no difference at all on COM 7&8.

But, I just got back from the hospital and switched everything back on, and did a signal strength test on the TV which showed they were both back! So I did a manual search and got the channels. I did the same with the Humax, and managed COM7 but COM8 was 0%, but then it zoomed up to 39%, so I did the search and it picked the channels up, but with rather poor quality at times. But at least the channels are there now.
So, I went onto the BT box - and it couldn't see any channels!

So, there's hope, but I'll report it and see what happens!.

link to this comment
Bob B.'s 7 posts GB
C
Chris.SE
sentiment_very_satisfiedPlatinum

5:48 PM

Bob B.:

Oh well, as you say there is some hope! But with Planned engineering at Sutton Coldfield, it may be better to wait a few days and see what develops. See what your neighbours are getting as well.
Frankly, although the list of Planned Engineering just says "Possible service interruptions", based on past experience, I wouldn't trust Freeview or Arqiva to give accurate detail, and that there could be weak signals and/or some multiplexes periodically being off-air!

link to this comment
Chris.SE's 2,543 posts GB
Wednesday, 4 December 2019
B
Bob B.
4:14 PM

Chris.SE:
Thanks Chris.

All but one channel that I've lost (the ones I use, at least ) are HD, so at the moment, I've just changed the recorders to record the SD channels. So, I'll take your suggestion and forget all about the problem - for a little while!

link to this comment
Bob B.'s 7 posts GB
Thursday, 5 December 2019
J
John Martin
sentiment_satisfiedSilver

1:29 PM

So when the rich people get G5 what will the free users be left with

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John Martin's 101 posts GB
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