All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
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.
| link to this comment |
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.
| link to this comment |
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
| link to this comment |
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.
| link to this comment |
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.
| link to this comment |
Briantist: This is the knock-on effect of the creation, and then shut-down, of the ITV Thames Valley non-franchise news region. ITV plc were permitted to move Oxford to the new Thames Valley region in Variation 3 of their 2004 licence (issued on 10 March 2008):
http://licensing.ofcom.or….pdf
"In addition, the Licensee shall include in the Licensed service in the Central South region a weekly average of at least 5 hours 20 minutes of news programmes of particular interest to persons living in this sub region. The Central South service may be shared with the ITV Meridian West service, as a Thames Valley service."
And then in Variation 6 of 19 June 2009, the reference to Thames Valley was removed:
http://licensing.ofcom.or….pdf
"News programmes in the sub-region served by the Oxford transmitter and associated relays may be shared with the Meridian West sub-region of the ITV Meridian regional Channel 3 service."
Since the ITV News website no longer has a regional map, it's hard to confirm that they're actually doing it, but I did note this story from Bicester (11 miles north-north-east of Oxford) in the Meridian section: Fire crews tackle Bicester blaze - ITV News
| link to this comment |
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.
| link to this comment |
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.
| link to this comment |
Mike Harris:
Digital UK Industry - Technical news archive 2013 says COM4/SDN on C58. The other two moves - G.O.L.D. to 26 and Home from 26 to 54 - are also on COM4/SDN.
The new BT Sport channels are on COM6/ArqB: C55.
| link to this comment |
Friday 15 March 2013 2:52PM
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.