All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
G.Hodson: Yes, it's quite likely you will be able to. Depending on the software on your box, when you retune, it might ask you which set of channels to store, it might store the strongest (presumably Waltham if your aerial points that way, although Belmont is more powerful and closer), or it might store the first version that it encounters. The second set might be stored somewhere else in the EPG.
If it stores the first version, you would probably get BBC A, D3&4 and Arqiva A from Belmont, and SDN and Arqiva B from Waltham, as the Belmont frequencies are generally lower than the Waltham ones.
See Digital Region Overlap for thoughts on how to get the services you want.
Note that Belmont Arqiva A and B don't reach full power until November, as they clash with services from Tacolneston. However, SDN, Arqiva A and Arqiva B have the same content at every English transmitter.
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Jack: Have you retuned today? All multiplexes (except for BBC A) have moved to different frequencies this morning. You will need to do a full retune (also called Full Reset, Default Setting, First-Time Installation, or Virgin Mode) to ensure that the box forgets all previous settings.
Can you provide a full postcode?
This is the last set of changes at Craigkelly.
If the retune doesn't fix the problem, check that it is not on the list of boxes that don't support 8K mode at http://www.digitaluk.co.uk/2kequipment and isn't on the list of problems with the larger Network Information Table at http://www.digitaluk.co.uk/splitnit . However, I would have expected you to have had problems with the BBC channels over the last two weeks.
Another common explanation is that you have too much signal. If you have a booster or amplifier, try removing it or turning it down. If that doesn't help, or you don't have one, try adding an attenuator.
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Richard McCulloch: I KEEP telling Brian to remove those.
These represent tentative future allocations. They might be used for Jeremy Hunt's pet Local TV project. Or they might not. They have not yet been auctioned and there is no date set for an auction.
The frequencies chosen are those with the widest coverage area that fall into the traditional analogue aerial group, or just outside it. (Craigkelly is counted as Group K/Wideband because Channel 5 was up at C48, although many viewers wouldn't have changed their aerial for this.) A local TV service for a specific city or town might get a different allocation covering only that area, allowing the NEW7 and NEW8 frequencies to be used for something else.
You are not missing anything, you won't expect to find anything else if you rescan, and they might never be used for TV at all as there are plans to allow broadband providers to use these 'white spaces'.
The planning may have to be completely redone as these 'assignments' were based on old versions of the plan, before international agreement on the frequencies for Ulster, Tyne Tees and the south and east of England was reached, and predating the Europe-wide agreement to release C61 and C62 for 800MHz mobile phones/broadband.
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sugapriya: All providers are supposed to provide some way of receiving the Public Service channels without a subscription. However, I can't find any details from Virgin Media on how to do this.
The contract with Virgin Media states that the box is theirs and should be returned if you stop subscribing. However, you often find that they don't collect it, so you often see boxes on eBay. I don't know if it's possible to watch free channels just by plugging a box in.
You're certain that it's a Virgin Media cable connection, not a satellite dish connection? These use the same 'F' connectors, which screw into the box. Aerial cables are usually plain push-in 'Belling-Lee' types. Some aerial installers do use 'F' connectors for wall-plates, though, as it makes a more reliable connection.
At your location it should be easy to find a location to install a rooftop aerial that gives reliable results. It should only require a small aerial. Second best would be an aerial fitted in the loft, and worst an indoor aerial, though you might still get good results, as you're not that far from one of the largest transmitters in the country.
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Dale:
The switchover is intended to be complete by the end of 2012. Check Digital UK - When do I switch? for the dates for your transmitter, or we can check if you provide your full postcode.
I have no idea about whether all the channels will decide that they no longer need to be 4:3 safe. Some viewers are likely to be sticking with 4:3 sets converted using an external box (particularly for second TVs). It's really up to the channel. Of course when showing content that was recorded 4:3 (e.g. archive content predating widescreen) they are likely to show it 4:3 and put the logo in the 4:3 area.
The logo - usually called a DOG, for Digitally-Originated Graphic, though that's reallly a term from the analogue era - is directly encoded in the picture so it cannot be removed, or therefore moved.
I assume that the logo - which is animated on some channels - is generated by the playout equipment, and changing its location isn't that difficult to do. It probably depends on the exact equipment and how old that equipment is.
I would hope that BBC One, BBC Two and ITV1 continue to be DOG-free, though BBC One HD has gained a DOG. I can't remember right now if Channel 4 has a DOG.
HD transmissions are required to be in 16:9, so it's likely that the DOGs will move as channels change from targetting SD to targetting HD equipment.
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Richard Abbott: I'm afraid we need a full postcode to see exactly what the situation is for you.
Signal propogation does change over time, and that can lead to increased interference or increased or decreased signal levels, any of which might be the cause of the problem. Nightly changes are usually down to Tropospheric Enhancement, when a cool/warm air boundary develops in the upper atmosphere around/after dusk. Signals can refract off this boundary when they would normally travel through.
If signal levels are fairly high, your problem could be caused by the signal you do want being reinforced by enhancement, resulting in too much signal overall. If you have a booster or amplifier, try it without, or turn it down. If that doesn't help, try adding an attenuator.
If signal levels are low, you would get best results by moving or replacing the aerial, or replacing the cable so that it loses less signal. If it's down to enhancement of a distant transmitter, rotating the aerial slightly to point further away from that distant source, or replacing with a more selective aerial, is all that you can do.
Other sources of interference causing problems at specific times would be street lights, thermostats or central heating pumps.
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Chris: Yes, the broadcasters use these dots to indicate changes. As far as they're concerned, the box should be ignoring these dots. Contact TVonics for suggestions - TVonics Store - Product Support
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David C, jb38: Considering that the signal levels from Darvel have increased greatly in the last couple of weeks, I suspect that the nightly variation is causing you to have, overall, too much signal at night.
I realise that sounds like my default answer to everything, but it's not a commonly-understood problem!
If you have a booster or amplifier, remove it or turn it down. If not, or that doesn't help, try adding an attenuator.
Signal levels as reported by your TV or box could be substantially lower than 100%, and yet have too much signal, for two reasons. Firstly, the box's strength meter could be calibrated for test lab conditions rather than real-world conditions. Secondly, some boxes are known to display a low signal level when they actually have a high one. I conjecture that this is because they're reading off the gain setting from the automatic gain control, but the AGC is automatically turned up when it can't decode the signal, so it's assuming lots of gain = low signal.
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edin: You have to have a "Freeview HD"-branded box or TV to receive HD channels. Just an 'HD Ready' TV is not enough.
HD Ready indicates that the TV can accept and display HD signals from another source. It might have an integrated digital tuner, but it won't implement all the standards necessary for HD TV in the UK. These are:
- DVB-T2 (not just DVB-T) for the multiplexed signal
- MPEG-4 AVC/H.264 for the more efficient compressed picture
- The BBC's special Huffman tables to decode the EPG data
If you're using a PC with a TV tuner card or USB tuner that claims to be able to do HD, it may be able to do it overseas, but not here. Some other countries use the older MPEG-2 video compression on DVB-T, and some use MPEG-4 AVC on DVB-T, but here DVB-T2 is required.
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Tuesday 14 June 2011 4:32PM
NottsUK: It's my belief that the BBC's use of 1440x1080 is using the Kell factor, to try to avoid annoying artifacts caused by the sampling rate matching the black/white transitions of high-density patterns. 1440 is a Kell factor of 0.75, matching the Kell factor used for analogue SD transmissions and close to that for digital ones.
See Kell factor - Wikipedia, the free encyclopedia and More than just a pretty face... for descriptions of the Kell factor, and the factors used for UK broadcasting (we are/were CCIR/ITU-R System I). The digital factor is a little wrong because the BBC are required to use 720x576 for the main channels, a factor of 0.703, while for 4:3 broadcasters are allowed to save some capacity by using 544x576. A 1.0 ratio would be 768 pixels per line (multiply 576 by 4/3) so 544 is a Kell factor of 0.708.
That said, broadcasts on a system using solid-state CCD cameras and generally viewed on LCD or plasma sets should probably have a higher Kell factor, though the broadcast 1080i is of course interlaced and therefore would suggest a lower factor. Perhaps the fact that the BBC generally still use CRT monitors, for their colour reproduction capability, has affected their thinking here. The Kell factor is stated as being subjective, so it is a matter of taste.
Of course 960x1080 is a factor of 0.5, on the low end even for interlaced pictures, but 720x1080 (factor 0.375) would not have been acceptable.