All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.Oh, and unless they sort out the frequency allocation before August, the BBC multiplex will have to move again some time in 2012 to free up C61 for 4G mobile phones.
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Brian: I think you've already entered a few of these changes, but in case it helps, here's everything that seems to have changed or that you don't have on the site already. I've put a # where there's a proposed move to a channel that will be released.
Border
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Caldbeck: SDN restricted to 15 kW at 598.5m until further notice. (PSB aerial is 619.5m) ArqA and ArqB are listed with this as the licensed height.
South West
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Huntshaw Cross: SDN, ArqA and ArqB restricted to 4kW until further notice. (No mention in latest DSO Details.)
Caradon Hill: ArqA antenna restrictions apply until further notice.
Stockland Hill: ArqA and ArqB restricted to 10kW until further notice (DSO Details has SDN as well, a number of notes relating to all COM muxes are missing from SDN's tab.)
Wales
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Moel-Y-Parc: SDN restricted to 2.5kW until 3 October. ArqA restricted to 2.5kW until 5 October. (DSO Details says September, 3 Oct is a Monday so I think 5 Oct is more likely.) ArqB subject to a reactive power restriction of 5kW until further notice.
West
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Mendip: ArqA increases from 10kW to 12.5kW on 28 September. (We knew it got an increase, but not how much. This is when it changes to 64QAM mode and loses its current +167kHz offset.)
Portishead: D3&4 moves from C52 to C62 on 28 September.#
Woodcombe: D3&4 moves from C52 to C62 on 28 September.#
Grampian (STV North)
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Durris: SDN moves from C52 to C23 on 15 June. Currently restricted to 20kW and 608m (main aerial is 639m). (ArqB out of date - DSO Details has the correct info.)
Scottish (STV Central)
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Darvel: SDN, ArqA and ArqB transmit from reserve aerial from DSO 2 (25 May) until further notice.
Rosneath VP: From DSO 2 (25 May) to 22 June, ArqA and ArqB subject to a reactive power restriction of 200W 'if required'.
Central
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Oxford: SDN, ArqA and ArqB restricted to 12.5kW after switchover until further notice.
Andoversford: BBC A will start up on C62 at DSO 1 next Wednesday and move to C50 at DSO 2.
Knucklas: BBC A will start up on C49 at DSO 1 next Wednesday and move to C39 at DSO 2.
Ross On Wye: BBC A has a note marker but the note is missing. It was due to start on C62- at DSO 1 next Wednesday and is now allocated C50.
Yorkshire
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Belmont: ArqA and ArqB now launch on final channels (C53 and C60), restricted to 4kW until 23 November.
Emley Moor: ArqB subject to reactive power reduction of 87kW if required 'until further notice'.
Chesterfield: ArqA and ArqB restricted to 40W until 12 October.
Sheffield: ArqB starts on C63 at DSO 2 (24 August) at full power (1kW) and moves to final channel (this has C49, DSO Details has C39) on 27 September (which is a Tuesday: should be 28 Sept? DUK also has 27th.)
Anglia
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Sandy Heath: D3&4 and HD use transitional S1 antenna until 27 June 2012.
Sudbury: ArqA starts up at DSO 2 (20 July) at 3kW, replacing Mux C on C54 at 1.5kW, 'until further notice'. ArqB starts up at DSO 2 at 2.2kW replacing Mux D on C50 at 1.1kW, moves to C63 (at 2.2kW) on 16 November.
Clacton: Claims BBC A starts up on 6 July on C49 - which is the allocated channel. DSO Details has C48 from 6 July until 2012.
Tacolneston: Mux 2 moves to C59 on 17 August, before DSO 1!
Meridian
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Hannington: ArqA restricted to 20kW from DSO 2 'until further notice'. ArqB starts up on C41 (final channel is C47) and restricted to 20kW. (Good old Ofcom, C41 is allocated to SDN at this transmitter and there's no note. DUK shows final channels at DSO 2 but does show two 'COM late power up' events.)
Midhurst: ArqA subject to a reactive power restriction to 5kW 'if required' 'until further notice'. ArqB restricted to 1kW 'until further notice'.
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AVC is ISO/IEC standard 14496-10: MPEG 4 Part 10 Advanced Video Coding. It's also known as ITU-T H.264. It's now in its 6th edition, incorporating various corrections, amendments, and extensions for 3D, but there isn't really a 'version 2' as such. It describes how the picture data is encoded - making use of the fact that each picture generally changes little from the previous one to reduce the amount of data that has to be transmitted.
The profiles define what features of the standard are available to be used - it isn't all mandatory, so basic profiles can be used for less powerful devices and the stream can still be used for more powerful ones. The levels define the maximum data rate and amount of storage required to decode. (An encoded picture refers back to previous pictures, so those previous pictures have to be available for the decoder to read them.)
It's possible that Channel 4 have newer encoding hardware and are using some features not widely used by the other channels, but still part of the High Profile. Or maybe it's a feature that was specified a bit loosely before and was tightened up in a correction or later edition. Most likely, though, the box has discarded a picture that a later picture refers to, possibly because it doesn't have enough memory to truly meet Level 4.
H.264/MPEG-4 AVC - Wikipedia, the free encyclopedia (RG47SH)
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Adrian: Sounds like the Blu-Ray player's power supply isn't right, generating electrical noise. I'd get it replaced. Can the TV tune into Freeview channels when the Blu-Ray player is on? If it can't, that would reinforce the idea.
Otherwise, just try to keep the aerial cable away from the box as much as possible. If you have a fairly thin aerial lead going to a wall socket, consider replacing it with a better one. Online Satellite/TV/FM/DAB Cable, Leads and Connectors sales. message is definitely coming from the Humax, not the TV? The SCART dongle has a really, really, really thin lead that I wouldn't trust in the slightest (it should have at minimum 10 of 21 wires plus shielding). Again, keep it away from any other electrical equipment. (RG47SH)
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Julie: It honestly sounds like the second tuner and the RF modulator have died - possibly they were damaged by the water. The Humax uses the same tuning information for both tuners.
I recommend that you get an aerial installer to check the aerial and any junction boxes or other equipment outside are properly waterproofed. Sometimes installers orient the aerial so the connections are on top, which makes them easier to connect, but means that it's easier for water to get in and it's got nowhere to go except down the cable. If set up so the boxes are on the bottom, water generally doesn't get in and if it does, it generally drains out of the lid rather than down the cable.
On the Humax, 30-32% is about 53-54 dBuV, which is within the recommended range of 45-60 dBuV. 100% is an outrageous 95 dBuV and I can only think they calibrated this to the most it could handle in the test lab with only one signal generator running. In practice it has to be far lower so that the combination of all six multiplexes (seven, with the temporary HD mux) and five analogue channels doesn't overload the tuner.
I'd expect you to get higher signal strength on Mux 1 (C52), Mux 2 (C40), Mux B (C46), and Mux C (C50), because they transmit at double the power of Mux A. Mux D (C49) is a little lower. However, there can be differences in how the signal travels so there may be interference or lower levels on some multiplexes some of the time.
If you're tuning manually, you need to tune all six (standard definition) multiplexes to get all the channels.
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Julie: I'm not sure if you mean that the RF loop out isn't working at all - that a TV connected to it won't even show the analogue channels - or whether you just mean that a preset on the TV tuned into the Humax's own output isn't working. The 'Default Setting' option resets the Humax's output to its default value, which I think is 36. If you moved it previously, you'll need to reset it to the value you chose before.
You may have needed to do this to get Channel 5 analogue to work, since that's on C37. I find that with the Humax on standby, it still seems to cut the looped-through signal around C36 even though I've moved the RF output to a different frequency - Mux C at Crystal Palace (on C34) never works on the TV when the Humax is on standby, and Channel 5 is more snowy.
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John: When the broadcasters make changes to the transmitters, they often add a dot to the end of the region name, so they know that a change has gone through. You probably have one with a dot and one without. I believe the boxes are supposed to ignore this, but not all do.
It also ought to be possible to select top preference and second preference, in case you actually want services from two regions, but again, not all boxes allow this.
What make and model of box do you have? It's worth checking to see if there's been an update that you've missed - particularly if this is a new box but could have been sitting in the shop or warehouse for a while.
The 21 services region is likely to be the BBC A multiplex, while 18 services is likely to be the low power Multiplex B - all services on Mux B are also on BBC A for the next 10 days, except for Sky Sports 1 and 2. On the 13th, Multiplex B closes for good (at Sandy Heath) and is replaced by the HD multiplex.
It may simply be that the box is telling you it's found three different versions of BBC Four, CBeebies, Red Button and the BBC radio stations.
My understanding is that it should also have listed the ITV channels if your signal quality is good enough to receive those. The prediction looks reasonably good - have you had Freeview before? Are you using an outdoor, roof-mounted aerial, or a loft aerial?
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Lost without TV: Check for a broken, loose or disconnected cable. Also, if you've tried to split the cable, disconnect the splitter - each tuner in each Freesat box (you may have two if it's a recorder) has to be able to send a signal back up the cable to the LNB to select the correct mode for the channel.
If you've added a diplexer, to combine aerial signals onto the same cable, check that it's wired correctly and isn't blocking the voltage sent from the Freesat box to power the LNB, or the mode selection signals.
If you've replaced a cable, it may not be the right sort. Regular TV 'low-loss' coax drops a lot of signal over its length, compared to 'satellite-grade' cable.
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John P: There are some hills blocking line-of-sight to Waltham as well as the church. The prediction, which includes terrain but not buildings, is variable to poor. Very careful siting of a fringe reception antenna might work, but it's also likely to be expensive.
All BBC services are free-to-air on satellite, but some ITV1 regions are only available encrypted, requiring a Sky box and viewing card. ITV1 Central East is one of them - weirdly, it's the only separate news region that is, while there are some news areas that have more than one advertising micro-region free-to-air.
You can get a dish, box and viewing card from Sky without a subscription for £175, including installation. See FREESAT from Sky - Call now to order .
You may find it simpler to just watch your preferred local news bulletin online. See BBC - BBC One Programmes - East Midlands Today for the BBC, and
Central Regional News (ITV Central Tonight) - ITV Local
for ITV. (RG47SH)
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Sunday 3 April 2011 9:12PM
Reading
timonthenet: This is the 'phony war', not the real switchover yet.
At Waltham, the only change *so far* has been the move of Mux A from C26 to C29. Mux 2 remains on C23 for the next 10 days.
On the 13th, Mux 2 moves from C23 to C31. This is still low power and not the 'proper' switchover.
The 'proper' switchover starts on the 17th of August, when BBC Two analogue switches off, and Mux 1 moves to C61. ITV1 analogue will temporarily move to C64, meaning if you select channel 3 on an analogue TV you will get nothing, and if you select channel 2 you get ITV1.
Two weeks later, on 31 August, the remaining analogue channels turn off. Mux 2 moves to C54 (as D3&4). Mux B is turned off. Mux C moves to C56 and changes mode (as ArqA). Mux D moves to C57 and changes mode (as ArqB). HD services start on C58.
In October, Mux A changes mode (to become SDN), which will probably require a retune, although it will stay on the same channel.
I realise these early retunes are confusing, but they're happening to ensure that you don't lose services when The Wrekin goes high power - BBC on Wednesday, the other channels two weeks later on the 20th.