All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
R.Strawson: I would strongly advise against getting an aerial from a high-street retailer or DIY store. They don't know what they're selling. The MZ40T is a 'contract' type: these tend to have very uneven response across the band - the gain on one channel may be very different to that on another, giving strange results.
At your location I would go for a small log-periodic such as the DM Log or Log40 at 
Online TV FM DAB Aerial sales . You are in a very strong signal area and should have no trouble unless trees block line-of-sight to the transmitter.
If you have a booster, you should remove it. It's very unlikely to be doing anything useful and could easily be overloaded. You may find that you need to use attenuation even with a lower-gain aerial.
I would also check that the cables are in good condition. If they've been up for more than 10 years, replace them. Use 'satellite-grade' cable with copper-braid-over-copper-foil screening, such as Webro type WF100. Ensure that you clip down the cable as it passes over brickwork and tiles - see Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads for ensuring it can't move.
Your problem could well be that water has got into the cable, which changes the cable's performance, increasing losses but increasing losses at higher frequencies to a much greater extent than lower ones. Or, the cable run could just be too long - the longer the cable, the more signal is lost, and it's worse at higher frequencies than low ones. 
Brian Barron: 
howtoreceive only lists analogue, and various internet video sites. It isn't available on Freeview (it would appear on 
DMOL Pre-DSO Multiplex Channel Allocations if it were on one of the regular multiplexes, and the Manchester local multiplex is listed on DMOL Post-DSO Multiplex Channel Allocations ).
Because it's right up at C62, you're likely to need a wideband aerial, Divis uses mostly Group A except for Mux C on C48. (You also need a wideband for TG4, on C59.)
Ofcom list Restricted Television Service Licensees at 
Ofcom | Restricted television service licences , where they indicate that a digital service licence may be possible, though probably not until after DSO. One thing's for certain - they won't be staying on C62, that channel is being cleared for 4G mobiles. Now the main UTV-region plans have been published (25 May), it may be possible to plan the new location, although an RTÉ multiplex (carrying at least RTÉ One, RTÉ Two, TV3 and TG4) is due to be fitted in somewhere as well. Jane Stevens: Digital UK shows a very high 99-100% probability of reliable reception with a roof-top aerial. A well-sited loft aerial is still quite likely to give good reception.
If you have an amplifier, try it without - you really shouldn't need one at that distance.
If you've just retuned in order to pick up a new channel - I know 'Really' launched recently - your box may have picked up the wrong transmitter, particularly if you retuned in weather conditions that cause signals to travel further than usual.
Otherwise, I'd suspect that something is no longer connected - again, signals could still be strong enough for something to be detected even without the aerial. Check for any breaks in the cable, that the connector on the end is making good contact with the input on the TV or receiver, and that it's securely connected at the aerial. Peter: Beardsley Way looks like blocks of flats on the Birds Eye view on Bing Maps, are you using a communal aerial system?
If you are, you may find that your building's owner has used a channelised system, which filters and distributes only the channels that Crystal Palace used before HD was added. It would need to be extended for HD, to include C31 as well as all the others. You may find that they're not willing to do this, given it's now less than a year before the whole thing will need to be reconfigured for switchover.
If you have your own aerial, I can't see what the problem would be, as this is a very strong signal area. See Single Frequency Interference for thoughts on what might be blocking this one frequency. P.JONES: Check for 'sharpness' settings in the TV's configuration menu - though usually they come configured with too sharp a setting.
A new TV will usually have a native HD resolution, and have to upscale SD broadcasts, so some blurring is inevitable as the screen resolution is not an exact multiple of the SD picture's resolution. Again, worth seeing what options are available to correct this. Ian: Nottingham is in the East Midlands.
John Robinson: Looks like that paragraph has been written by some political junkie, not someone technical. Very, very careful aerial design and positioning is going to be necessary to avoid co-channel interference on the edges of the petals, between the signal transmitted on each antenna for each sector. Of course they may have taken this into account and not expect any real coverage in the edges of the petals, note that The Wrekin petal A and 2 are on different frequencies.
There is no channel zero, someone forgot to fill it in. Given what they've done elsewhere I assume it will be C56 as on the other two petals from Winter Hill. Briantist: True, but that's confusing UHF channels with Logical Channel Numbers. The document clearly means UHF channel numbers.
Ian: MATV is still licensed in Leicester under a Restricted Television Service Licence, though there are reports that it has now shut down. It's possible that they will be offered a chance to bid for an interleaved frequency, as an existing RTSL for Leicester.
If it is still running, it would be broadcasting on C68 from a mobile phone tower near Ratcliffe College - 
mb21 - The Transmission Gallery . Damian: With the correct aerial, pointed in the correct direction. Check Digital UK's postcode checker to avoid disappointment.
Note that Stockland Hill's commercial multiplexes remain on low power until after London's DSO on 18 April 2012, so you might not be able to get it now, but might be able to after that. Ian: The government decided to release one-quarter of the frequency spectrum used for analogue. Ofcom decided they didn't have the power to force the three commercial operators to transmit from any new sites. I disagree, but there you are.
Ofcom are currently running a consultation on extending the duration of the Mux C and D licences, see 
Ofcom | Television Multiplex Licence Renewals . You have until the 18th of August to respond. Unfortunately they've already issued a new licence for Mux A.
Digital UK's predictor reckons you have a reasonable chance of getting the commercial multiplexes by pointing an aerial over the Pennines to Emley Moor, starting some time next year. Again, not too sure about that! Sarah: Do first check that the receiver window on the TV is clean and that there isn't anything blocking the path from the remote to the receiver. It can often be as simple as that. Andy Thomson: It sounds like your TV has an automatic retune function. Check in the manual to see if there's a way to turn this off. Then, as Mazbar says, tune in manually.
Also, talk to LG about whether they will make an update available that allows you to select the region you want to use. Newer equipment is now doing this. oldpaul100: At present there are no new services carried after DSO that did not already transmit before DSO.
Although the BBC A, Arqiva A and B multiplexes do have more capacity after switchover than their pre-DSO equivalents, the same amount of SD capacity is lost by converting BBC B to DVB-T2 for HD broadcasts. 24Mbps gained, 24Mbps lost. The additional capacity on the Arqiva multiplexes after DSO is being matched by the BBC *before* DSO from the spare capacity on Multiplex B, after they closed all the services that won't fit onto post-DSO BBC A.
So far that's only Sky Sports 1 and 2, which you won't see above as they're encrypted (this site only shows free-to-air channels). The matched capacity on Arqiva A isn't yet in use, because some transmitters have switched over and converted Mux B to HD, but haven't yet converted Mux C to the higher-capacity mode (e.g. Sandy Heath, where this won't happen until 14 September, and Mendip on 28 September).
In terms of what goes where:
BBC Four, CBeebies, BBC Parliament and the BBC radio stations move from Mux B to BBC A at DSO 1 - for the two weeks between step one and step two, they are carried on both multiplexes;
Sky Sports 1 and 2 move from Mux B to Arqiva B.
Brian will update this page at each stage of DSO. For example, the Sheffield and Chesterfield pages both already show PSB1/BBCA in place of Mux 1, with all the BBC channels. Kim: Digital UK's engineering works information is showing that works are planned at Crystal Palace this week, with occasional service interruptions. That said, I (in Caversham) am not having problems right now.
Check whether analogue is clear, or at least no more snowy than usual. If it is worse than normal, check that the aerial and cables are intact and that the cables are properly connected. If you're using a distribution amplifier, check whether the power supply is working. Ian: It's all about what is achievable from the existing main transmitter network. That leads to some weird locations. Burnley, pop. 73,000, because it's off the existing 6-mux Pendle Forest transmitter; Mold, pop. 9,568, from Moel-Y-Parc, being the only town that could be covered. I can't see a town of < 10,000 people having a viable TV service!
In fact I can't even tell why Pendle Forest was included in the original 81 DTT sites, as it doesn't really cover any major population centre not served by Winter Hill. It was quite powerful pre-DSO, actually no power increase on the first four muxes at DSO; perhaps it filled a hole in the original Winter Hill coverage, before the equalization programme of 2000?
Again, Cambridge and Norwich are proposed locations. The south and east edges of the country are hard to serve anyway with overseas co-ordination required, Ipswich is likely too far from Sudbury and the transmission would head out toward Belgium and the Netherlands rather than being contained.
The mucking about with many DSO steps at Waltham, Sandy Heath and Sudbury indicates what a problem the terrain of eastern England is. It just may not be possible to find a free channel providing enough space for a Derby service off Waltham. Using relays has obviously gone in the 'too expensive' bucket. 'Me': ITV1 +1 and ITV1 HD broadcast on macro-regions only. The whole of Wales, West and Westcountry is one macro-region, and ITV plc have decided to use the Wales regional output as the service for this macro-region. Lawrence: It's probable that you now have too much signal. Try turning down the booster, or replacing it with a passive, unamplified splitter. Trust me, Reading does not have a population of 800k. 250k if you include the whole conurbation, about 150k in the borough boundaries. The whole point is that it is a local service, otherwise you might as well do a single service from Hannington for Reading and Basingstoke rather than Ofcom's 'petal' idea.
The coverage map looks fine to me - little spotty in Woodley (south-east of town centre) and Tilehurst (west Reading). I'm surprised they think the coverage in Caversham (north of the Thames) is that good, considering that is where the Hemdean relay is.
Actually I'm a bit surprised Hemdean isn't included, considering that C51 would be in-group for that relay as well. Perhaps it would interfere with the Basingstoke petal. Or perhaps Arqiva just don't want to run a line feed for it (there's too much reprocessing delay to do an off-air SFN even with a 1/4 guard interval). Steve P: You cannot stop a transmission at an arbitrary boundary. If the signal is strong enough to be received in all parts of the coverage area in Liverpool itself, there's inevitably going to be some bleed over into areas beyond the city. This isn't intentional coverage, though it will cover some 'dormitory' areas. Jane Ashton: You're most likely using the Rowridge transmitter on the Isle of Wight, which switches over next March.
Digital UK predicts a good chance of reliable reception now on Mux 1, 2, A and B, while C and D are expected to be variable. It's always more difficult on a long sea path, and you also have to contend with interference from northern France - I believe they are further along in their switchover than we are.
A new, taller mast has been built at Rowridge, to the west of the old mast, to improve coverage after DSO, but I'm not sure whether services use this mast yet.
It's still worth checking that your aerial is intact and pointing the right way, and the cables are in good condition. Cables should be well secured so they can't move about when the wind blows - if they have been able to move, they may have worn away the outer insulation against tiles or brickwork, or just pulled out of the connection. Also, the insulation does perish with exposure to UV light - as a rule of thumb, outdoor cables last about 10 years. Damaged insulation lets water in, which increases the amount of signal lost along the cable and can damage equipment if it manages to run all the way along the cable.
For other ideas, see 'Freeview reception has changed'.
The postcode predictor reckons that you'll get a very good chance of reliable reception from the PSB multiplexes after switchover, but the COM multiplexes may be variable. Once they reach their final channels on 18 April 2012, you will get better reception by rotating the aerial so the elements go up-and-down rather than side-to-side, as Rowridge will then transmit more power on vertical polarization than horizontal. Don't do it until then, as it doesn't use vertical polarization at all until switchover.
The change to VP is intended to combat interference from French stations. Mike Roberts: Yes, you're likely to get the channels more reliably than you do now, though this is never going to be all that reliable with the Pennines in the way. The commercial multiplexes will be co-channel with those from Moel-Y-Parc so are unlikely to work. dan: Is your box quite old, say 2002-2004? If so, it may not support the 8K mode used after switchover. You can find a list of some boxes known to have this problem at 
http://www.digitaluk.co.u…ment .
It might also possibly be a box that struggles with the Split NIT introduced in 2008 - the problem doesn't show up until you retune. Some affected boxes are listed at http://www.digitaluk.co.u…tnit . You might find the BBC channels up in the 800s, or somewhere else in the channel list. As KB Aerials says, you might also experience this if your box stores the first-found at the preferred channel number, and the signal from Belmont or Chesterfield is powerful enough.
If you're very close to the transmitter you might find that your signals are now too strong. I can check this if you provide a full postcode. If you have an amplifier or booster, try removing it. pete from Ewden: The Oughtibridge relay will switch over on 7/21 September along with its parent, Emley Moor.
Digital UK predicts that 99% of locations, within the 100m x 100m square that the centre of your postcode is in, should get reliable reception. Briantist: £25m is about what Arqiva and NGW said they would be charging a PSB for transmission from all 1,100 site, in 2005 money.
As far as population goes, re-read page 2 of 3 of Ofcom's document for the definitions of 'Gross Population' and 'DPSA Population':
"Gross population represents the total number of households that could receive the local multiplex if their aerials are pointing towards the appropriate transmitter.
"DPSA is an attempt to provide a more realistic estimate of the number of households that might be able to receive the local multiplex than gross population. The DPSA (Digital Preferred Service Area) is a prediction of the areas where a particular transmitter is likely to provide better signals than other transmitters. In those areas, it is reasonable to expect that households have aerials pointing at the transmitter in question and could therefore receive the local multiplex broadcast from that transmitter."
Where more than one transmitter is used, the 'gross' figure is the largest from any *one* transmitter, but the 'DPSA' figure comes from the sum of *all* transmitters. That has led to a few anomalies where the DPSA figure is larger than the gross figure.
If you're trying to represent the actual populations of those areas, might I suggest using 
List of largest United Kingdom settlements by population - Wikipedia, the free encyclopedia or List of urban areas in the United Kingdom - Wikipedia, the free encyclopedia - however, that is people, not households. If you're going to adjust a population figure to get approximate count of households, using a figure for average occupancy, you need to *divide* by 2.41, not multiply.
On that basis I reckon you get 369,804 / 2.41 = 153,445 households in the Reading/Wokingham urban area, and therefore the proposed local multiplex would cover 235% of them on a gross coverage basis, 91.2% in DPSA. mike Roberts: You often see claims that line-of-sight to the transmitter is required. It isn't. You definitely get the best signal levels if you do, and the least reflections, but you still get some signal (not necessarily enough to be usable) from refraction over the terrain.
Line-of-sight is also suggested because it is easy to compute possible signal levels. Most predictors - other than Digital UK's - use a simple free-space equation which can overestimate levels.
Aerials have a fairly wide acceptance angle - how wide depends on the aerial. It's likely that it has enough gain in Emley Moor's direction, not enough in Moel-Y-Parc's direction. Briantist is completely wrong to claim that a Yagi-type aerial receives as much signal from behind as in front, it is in fact far less (though not none). Betamax_Man: It's likely that your box has an automatic retune function, and that it also stores the first version of the channels that it finds, rather than the strongest. I would turn off the automatic retune.
At switchover, the best approach is probably to unplug the aerial before doing a reset. You can then plug it in when the scan reaches about one-third of the way through, or leave it out until the end, accept that it hasn't found any channels, then manually tune on the appropriate frequencies. See above for the UHF channel numbers to use. 65 MPEG-2 streams on satellite would require 5 transponders if you crammed them in as tightly as the Freeview SDN multiplex is (11 streams in 24Mbit/s, 33.8Mbit/s available from a satellite transponder gives about 15 streams).
Unless, again, you're going to insist that potential viewers upgrade to DVB-S2, but I note that DVB-T was specified for the DTT service.
I suspect you'll be lucky to find 5 spare transponders
Local stations had better not want to use any music; PRS want a minimum of £16,500 for broadcast rights: 
UK channels without a BARB rating
. You also have to pay PPL but I can't find a price on their website. That's only if broadcast in the UK, so those transponders are going to have to be found on Astra 2D or 1N UK beam - you could blow your whole budget on music licences if the channel ends up on a Europe-wide beam. jamesanthony: The Belmont transmitter has just started switchover, and therefore the BBC service. It's possible you would have had the issue even if you hadn't retuned.
If you want to use the Nottingham transmitter, the aerial should be set up with its elements going up-and-down rather than side-to-side. There should be enough cross-polar rejection to ignore the signals from Belmont. For 'X' type aerials you want the Xs to be standing up rather than laying on their sides - narrow rather than tall.
Your box might be one which won't discard channels it thinks it already has - you will have to delete the BBC channels so that it actually stores the manual-tuning results. If your box doesn't have a delete feature you'll have to unplug the aerial, do a full reset, then plug in after the automatic scan has completed. Then do a manual scan on the frequencies above - note that right now, SDN is on C67, ArqA on C63 and ArqB on C49, at low power.
On 24 August, ArqB moves from C39 to C48 so you will need to retune. Then on 27 September, SDN and ArqA move to their final channels.
Belmont's version on BBC A is on C22, so you can't just plug the aerial in after the scan gets to a certain point.
You haven't said exactly where you are so it's not possible to say whether you'd get better results from a different transmitter. Mike Myers: The software here treats the groups as a hard cut-off. In fact, aerials still have some gain just above the official edge of the group and also just below - Ofcom have used this as part of their planning, though do note that the official edges of the aerial groups have already changed a bit, to accommodate Channel 5, so an older Group B might not work as well up at C56 than a newer one.
You can see some aerial gain graphs at ATV Stock Aerial Tests , which indicate that at least some aerials have as much gain at C56 as they do at C40. clive: Group C/D aerials still have some gain below the official group - there isn't a sharp cut-off as there is above the aerial group. See ATV Stock Aerial Tests for a comparison.
Whether or not you need a filter for 4G will depend on where you are and where the 4G transmitters using the 800MHz band are. As Tacolneston uses horizontal polarization, and 4G base stations are expected to use vertical polarization, your aerial is likely to pick up rather less 4G signals than if it were vertically-polarized.
Please check Digital UK's prediction to figure out if you really are in a weak signal area - if you provide a full postcode I can check this. Post-switchover digital signals will be substantially stronger than before. The coverage area could even be larger than analogue, because while the new digital maximum power levels are lower than analogue, they are relatively higher than at most other transmitters. Other sites use a power level one-fifth of analogue, Tacolneston will be two-fifths. Peter K: I recently disassembled one that I used to use (before finding articles on why boosters are useless). The active part of it - the bit that wasn't just converting AC power down to DC - was one transistor.
A transistor amplifier basically works by a small flow of current between two of the three pins on the transistor producing a much larger flow between two other pins. The larger flow is related to the small flow, but not linearly - there is an exponential relationship.
The current can also only flow in one direction, while an RF signal flows in both directions. To correct this, the signal is 'biased' with a voltage about half that of the power supply voltage, which means it never has to flow backwards; the amplified bias is then stripped off the output with a capacitor.
The bias is set so that the expected size of the input results in the right amount of gain, in an approximately linear region of the amplifier's transfer function.
Digital TV requires a very linear amplifier, it cannot handle much distortion at all. If the input is larger than expected, the response of the transistor amplifier is no longer linear. If the input is particularly large, the amplified signal can reach the voltage of the power supply at the top or the minimum voltage that the transistor will pass, which causes clipping - a severe form of distortion.
The distortion caused by this, when you have multiple frequencies in the input, is known as 'intermodulation'. The effect is to cause errors in other carriers in the same multiplex, and/or carriers in other multiplexes, which - if there are too many - causes failure to decode, either intermittent or total.
You can also get problems if the power supply starts to fail, particularly if the capacitors in it fail and the voltage to the amplifier circuit starts to 'ripple', as the power supply voltage - therefore the maximum output - will be periodically getting closer to the peaks of the output, and clipping them periodically.
Any electronic circuit also adds thermal noise, caused by the random movement of atoms when hot (random movement of atoms *is* being hot). What's important is the signal quality, the ratio between the signal level and the level of noise. All else being equal, adding an amplifier adds noise, reducing signal quality. Only do it if the signal is too low for the box to decode, although if this is the case, you're either too far away, the aerial doesn't have enough gain, or have some other problem in your aerial system. A booster might give an improvement if the receiver is particularly noisy, but usually the receiver front-end is better built than your average booster.
It is usually necessary to amplify if distributing the signal more than a couple of ways, as the aerial gain just isn't enough to offset the loss in the splitter and the extra cable length - in this case, amplify as close to the aerial as possible, just enough to offset losses in the splitter and cables, and ensure that the input to the amplifier is lower than the maximum input it can handle (without distorting). Bill Procter: I assume that you are trying to use the Sheffield transmitter rather than Emley Moor, on the basis that you mentioned a retune event this week. If you are, the aerial should have rods going up-and-down rather than side-to-side.
If using Sheffield, you can't use the aerial-out trick, because Belmont BBC A is on C22 and Sheffield on C27 - the other PSB multiplexes will be interleaved.
For now, use these frequencies:
BBC A - C27
Mux 2 - C63
Mux A - C57
Mux C - C45
Mux D - C42
Mux B - C60
You can ignore Mux B if you don't have Sky Sports on BT Vision or Top-Up TV, because all the BBC channels are already on BBC A. Jean Timms: The responsibility for providing a good aerial and connections to it lies with the building manager. See 
PARAS - Professional Aerial Riggers Against The Sharks for some thoughts on who to contact. Some part of the building maintenance fees, or rent, should be going to maintaining the communal aerial system - insist that it is maintained.
The Digital UK predictor does show that there are a number of possibilities for the local transmitter, though the most likely is Sutton Coldfield. If the system is not channelised - only amplifying selected channels - your box could decide to tune in signals from a different transmitter rather than the best one that the aerial is pointing at, if it encounters that transmitter earlier in the scan. Try doing a manual retune using the frequencies at the top of the page. If that works, check whether your box automatically retunes itself - some do. If so, turn that feature off.
If a manual retune doesn't correct the problem, ask the building management to get the system properly set up, so that there is sufficient signal at the socket(s) in your flat. If the analogue pictures have also deteriorated, it's likely to be a system problem, and if it's affecting all residents, it probably is the aerial, or an amplifier, or an amplifier's power supply.
If the system *is* channelised, it will need to be retuned at switchover on 21 September. The levels might need to be corrected after the BBC high-power multiplex starts on 7 September. Steve T: The commercial multiplex operators don't want to pay the extra cost of transmitting from the other 1,000+ sites in addition to the 81 sites they used before switchover. Ofcom have decided that their powers don't allow them to require the operators to do it (I disagree).
Ofcom are currently running a consultation on renewing the Multiplex C and D (Arqiva A and B) licences: see Ofcom | Television Multiplex Licence Renewals . Multiplex A was already renewed last year, so that ship has sailed for about the next 10 years. You will *not* be able to get high-power BBC digital from the Derby transmitter from the 17th. This transmitter is an oddity, it relays BBC One East Midlands and ITV1 Central East from Waltham to an area that is otherwise perfectly served by Sutton Coldfield. It is therefore horizontally-polarized. Because it doesn't transmit BBC Two, and the available frequencies are so tight in this area, there will be no changes here on the 17th.
Instead, on the 31st, BBC A replaces BBC One on its current channel (its final location), and D3&4 replaces ITV1 on its current channel. HD will not start up yet.
A retune event is scheduled for 5 October, when the HD multiplex will start up and D3&4 will move to its final location.
ITV1 analogue takes over BBC Two's slot, at all relays except Derby, so that the BBC A multiplex can start up on ITV1's old frequency. This means that ITV1 will appear on button number 2 on most analogue TVs. This has no effect on the TV's digital tuner or set-top box. timonthenet: Best bet for you is Postcode Checker - Trade View .
This shows that the *only* change at Waltham, for a digital tuner, is Mux 1 closing (from C49) and being replaced with BBC A on C61. No offset is given so this will be 794000 kHz. The new mode for BBC A will be 64QAM, FEC 2/3, 8K carriers, 1/32 guard interval.
Mux 1 carries: BBC One, BBC Two, BBC Three, CBBC Channel, BBC News, BBC Red Button (105) and 301.
BBC A will carry all of the above, plus: BBC Four, CBeebies, BBC Parliament, and the radio channels, BBC Radio 1, BBC R1X, BBC Radio 2, BBC Radio 3, BBC Radio 4, BBC R5L, BBC R5SX, BBC 6 Music, BBC Radio 4 Ex, BBC Asian Net., BBC World Sv.
For the two weeks between the 17th and 31st of August, those channels new to BBC A will continue to broadcast on Mux B as well.
The HD channels will start up on the new BBC B multiplex on the 31st, replacing Mux B which closes. All four, including the ITV1 and Channel 4 HD channels, are on the same multiplex. This broadcasts using DVB-T2, 256QAM FEC 2/3, 32K carriers, 1/128 guard interval. You may need a new tuner card or stick to get them. They will also be compressed with MPEG-4 AVC, aka H.264, not MPEG-2.
On the 31st, Mux 2 closes and is replaced by D3&4 on C54- , 738 MHz with -167kHz offset so 737833 kHz. Mux C closes and is replaced by Arqiva A on C56, 754000 kHz. Mux D closes and is replaced by Arqiva B on C57, 762000 kHz. All of these will use 64QAM 2/3 8K mode with 1/32 guard interval.
Sky Sports 1 and 2 move from Mux B to Arqiva B (former Mux D) at switchover. 303 closes.
Mux A stays on its current frequency and mode setting until 12 October, when it changes to 'SDN', switching to 8K mode to match the other four SD multiplexes. It will remain on the same frequency. H Allen: All relays are 'Freeview Light' until further notice. The operators of the commercial multiplexes, which carry ITV4, refused the offer to broadcast from more sites than they already do, saying it was too expensive.
If they ever do, they are likely to choose large relays that cover a lot of population. Hagg Wood covers around 1,200 homes and I believe that is gross population, the number that *could* get a service from the transmitter, not those that *have* to.
Do check with Digital UK's postcode checker to see whether you could use a main transmitter after switchover.
Ofcom are consulting on the renewal of the licences for Arqiva's two multiplexes. See Ofcom | Television Multiplex Licence Renewals - it closes on Friday. Brian: Don't forget that switchover 'ends' at Belmont, Oliver's Mount and relays tonight.
("Ends" because while Mux C and D switch mode and move to final channels, they only get a 3 dB power increase, not to final levels until 23 November, due to the clash with Tacolneston.). Mark: To confirm, do you mean Multiplex A on C30 and BBC One analogue on C31, or do you mean LCN 30 "5*" and LCN 31 "5 USA"?
If you can't get 5* and 5 USA, but you can get LCN 10 "ITV3", the problem is most likely to be in the box itself - do a full reset/full retune/first-time installation.
If it is a problem on the actual frequencies, either there is something in the area also transmitting on C30 - perhaps a Sky box whose RF output has been set to this channel, or another device with an RF modulator such as a VCR - or simply low coverage.
The Digital UK trade predictor shows good reception on Mux A - C30 - at your postcode BH15 2BU, but poor at BH15 2AX. It looks like line-of-sight to the transmitter is blocked by higher ground at 2AX than at 2BU, which could explain the problem a little, although the other multiplexes aren't shown as significantly different.
The engineering work is to build a new mast, which has been erected to the west of the transmitter. I wouldn't expect the tiny difference in direction to have much difference between the two sites, though.
Is your installer orienting the aerial with horizontal polarization, rods going side-to-side? You're expected to get better results from vertical polarization AFTER switchover completes, but only after 18 April next year. Right now Rowridge transmits nothing on vertical polarization.
You should get very good analogue signals from the Poole relay, but it won't start broadcasting digital until 7 March and will then be a 'Freeview Light' transmitter, not broadcasting the commercial multiplexes at all. (BH15 2BU) obsidian eclipse: Off at shortly after midnight tonight, i.e. the early hours of the 17th, and potentially off and on periodically until 6am. Relays may take longer, see Digital UK - Relay transmitter switching times for details.
Most likely is that, because ITV1 analogue is replacing BBC Two analogue at all relays (BBC Two switches off), it will happen at an ITV1 programme junction. At sites where no analogue channel swap was required (e.g. Sandy Heath), BBC Two was turned off at the end of the final programme scheduled.
BBC Two has Chilean Miners until 00:20, then TOWN until 01:20. ITV1 has The Grudge until 00:20 then 'The Zone' (QVC) through to 02:25, so the logical cut-over point would be 00:20, though don't rule out 01:20.
After that, Mux 1 could go at any point.
Belmont DSO 2 is also tonight, and there is also a retune at Tacolneston to release C61 (which Waltham BBC A will use), so there may need to be some co-ordination between the sites, as Tacolneston is taking frequencies that Belmont currently uses. Brian: Also there is a retune at Tacolneston; Mux B on C58 moves to C66 and Mux C from C61 to C68. This is to protect against Waltham BBC A on C61 from tonight, and Waltham BBC B on C58 in two weeks. Mark A.: No, Wolfbane's *digital* predictor does not show Haywards Heath, because at the moment, HH does not transmit digital. It will do, from 30 May/13 June 2012 - it is a relay of Heathfield. Ben Hughes: The pre-switchover HD service is on the same power level it has always been on.
In your area, you're expected to be practically certain of having reliable reception. Check that you aren't overloading anything. If you have a booster, remove it. You could also try adding an attenuator to reduce overall signal levels (you could well need one after switchover).
Also check for possible sources of impulse interference. Keep your phone well away from the PC and the cables. Check whether the breakup occurs when the central heating thermostat or controller switches on or off. If it does, a cable upgrade to satellite-grade cable may be worthwhile.
The broadcasters' definition of 'reliable' is 1% errors over time. Nothing is totally guaranteed. Still, it's more likely to be too much signal than too little. J Darnell: Yes, the main part of your switchover ends tonight. It is expected to be complete by 6am.
Arqiva A and B will still be on restricted power from tonight until 23 November, but will be on final channels and modes, so you should not need to retune again unless you find you can't get those services.
The power restriction is to protect viewers of the Tacolneston transmitter near Norwich. Jamie: The Sheffield transmitter is not a good option for you. You should get better results from either Emley Moor or Belmont. If you want the Leeds news service, the aerial should point roughly north-west to Emley Moor, from which you should get good results now, including HD.
If you want the Hull news service, the aerial should point roughtly east to Belmont, which completes switchover tonight. Retune after 6am. You may not get the Arqiva A and B multiplexes - shown as Mux C and D above, except that Sky Sports move from Mux B to Mux D at switchover - until after the power increases in November.
My best guess is that your aerial actually points to Belmont and is getting the BBC A multiplex from there, although it does raise the question of where it's getting BBC Two analogue from, since that no longer transmits from Belmont or Sheffield. If it's notably weaker than BBC One, it's probably from Emley Moor. Jamie: For either Emley Moor or Belmont, the aerial's elements should go side-to-side. For Sheffield, they would be up-and-down. Most likely no-one on your street needs to use Sheffield, but you will see some aerials in the vertical position around the city, for those who do. Harry Lee: Some equipment gets confused if it finds more than one copy of a channel, or has information stored from before switchover. Try doing a first-time installation/full retune/factory reset.
I'm afraid I can't find an LG TV with that model number, can you check whether there is a longer model number on it anywhere? damo: It is your equipment. I've been using Crystal Palace fine all week, and I'm much further away than you are.
If there are any boosters, check that the power supply is on and working properly. If you can, remove or bypass them, you shouldn't need one where you are.
Otherwise I suspect a broken cable or connection. 
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