All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Nick: Sudbury has had to wait for Dover to switch-over so as to throw free the three final COMs channels. A few other transmitters have had to go through similar "temporary" stages, although at a year, this is one of the longer ones.
See the DMOL link I provided as it lists services by multiplex which are identified as either "PSB" or "COM".
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Nick: For Sudbury, a Group E aerial is semi-wideband as it spans Group B and Group C/D channels.
The other alternative is to use a Group C/D aerial for the COMs and diplex it with a Group B for the PSBs. Or the wideband may be suitable for the PSBs with it being diplexed with a C/D to pick up the COMs.
For diplexers, see Online TV Splitters, Amps & Diplexers sales
The one that "splits" at C51 should be suitable if the two-aerial approach is to be employed.
As I say, I'm not a professional so I don't know under what circumstances that may be better than a single Group E aerial.
Clearly the diplexer acts as a filter so on the COMs channels only the C/D aerial is used, and on the lower PSB channels only the other aerial is used.
See also:
Sudbury Transmitter
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Nick: I used Megalithia to plot the terrain between Hollesley and Dover transmitter and I reckon that you may have line of sight at 66 miles.
I am not so sure that the same is true of the location which is further north and closer to Aldeburgh.
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Sticks: It could be water in the cable.
HD from Stockland is on C29 which is what Channel 4 analogue used to use. Did you have any issues with reception of that channel?
The only other observation I can make is that despite being so close to the transmitter, you don't have line of sight to it.
The terrain drops down and there are two brows over which the signal is having to go to get to you:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
These correspond approxiamately to the areas of around about St Michael's Church and Manor House School and both of these areas have trees. So on the brow of those "hills" (shown in the terrain plot above) it would appear that there are objects (trees).
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Sticks: I have just noticed that there is a message at the top of this page about engineering works at Stockland Hill and the possibility of it being "liable to interruption".
I would ask, has this always been an issue? But if it has been tuned to Honiton for HD all along, then results may be poor or intermittent.
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Sticks: About possible water in the cable, check for damage to the insulation, such as chafing on a roof tile IF you can work safely at heights and have the appropriate ladders and knowledge to do so.
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Susan: The Commercial (COM) services changed channels from Sudbury last Wednesday.
See this page for a full list of services by multiplex (those that have a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
A multiplex is a single signal.
Try attempting manual tuning for missing multiplexes, if your receiver allows:
COM4 | ITV3 | C58
COM5 | Pick TV | C60
COM6 | Yesterday | C56
Failing that, perhaps your aerial needs replacing. See the posting I to Katharine immediately above yours in which I linked to another posting of mine which explains.
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Nick: For which channels are PSB (and which are COM), see the "DMOL" link I provided in my posting at 1:48PM.
Also see this page, particularly starting at the heading "Independent Television Commission: 1, 2, A, B, C and D":
Why do the six Freeview "multiplexes" have twenty different names? | ukfree.tv - independent free digital TV advice
For more general information on what Public Service Broadcasting is, type into a search engine something like {uk public service broadcasting}.
Basically, as explained in the link above, BBC, Channel 3 (branded "ITV1" by ITV Plc in England), Channel 4 and Channel 5 are Public Service Broadcasters and as such have obligations placed upon them. This includes achieving a particular level of coverage and which means the installations of small relay transmitters in populated areas that aren't otherwise served.
The PSB1 multiplex is for exclusive use of the BBC. PSB2 is licensed to D3&4 which is collectively owned by Channel 3 licencees and Channel 4. This multiplex must carry ITV1 (or STV in parts of Scotland and UTV in Northern Ireland), Channel 4 and Channel 5. The Public Service broadcasters can decide which other of their sister services they wish to carry on their PSB multiplexes.
You're now going to ask, why have they included ITV1+1 on PSB2 instead of ITV3? I imagine that the answer is down to the return they expect from the advertisers. Presumably providing an ITV1 one hour behind is seen as being more lucrative than ITV3. So it is all down to money and only ITV1, Channel 4 and Channel 5 must be carried on PSB2.
PSB3 is the only HD one, and whilst licensed to the BBC also carries HD services on behalf of ITV1 and Channel 4.
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I am not sure that Aldeburgh 23 and Sudbury 41 are classed as different "networks" or "regions".
Aldeburgh is a relay of Tacolneston. According to this site, both Tacolneston and Sudbury carry BBC East and ITV Anglia East. I would be interested to know whether, as far as the receiver is concerned that these are the same network/region.
Sandy Heath is the third Anglia transmitter and it carries "ITV Anglia West". So there appear to be two variants of ITV Anglia; "East" broadcasts from Tacolneston and Sudbury and "West" comes from Sandy Heath. Do you know different?
I receive from Emley Moor, but I'm in a location where I can usually pick up Belmont up off the back of the aerial.
Emley Moor and Belmont are part of different BBC and ITV1 sub-regions. When I run the automatic tuning function on my Sony RDR-HXD870 is removes 80-odd duplicates once it completes. This leaves me with all services from Emley Moor plus the BBC One and ITV1 from Belmont. So I end up with two BBC Ones and two ITV1s but not two of everything else.
On another TV, I have all the duplicates, with the highest logical channel number (LCN) being 937! So it would appear that how it works depends on the design of the set.
Freeview TVs usually store duplicates starting at LCN 800.
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D Green: Unfortunately not; the Commercial (COM) multiplexes do not have as wide a coverage as the Public Service Broadcaster (PSB) ones. The main reason being that the small transmitters like Rye don't carry them because the operators don't regard it as worthwhile to pay for them.
The UK now has a two-tier terrestrial transmitter network. 81 of the largest transmitters (largest by viewer population) carry all six multiplexes (three PSBs plus three COMs) and these serve around 90% of the population. (A multiplex is a single signal that carries multiple "services".)
The other 1,000 or so small "filler-in" relays like Rye carry only PSBs and serve about 8.5% of the population.
The reason for this is because the Commercial broadcasters operate for profit only and have no "Public Service" obligation. They were invited to increase their coverage and declined. For them to transmit from the 1,000 relays would roughly double their cost of transmission. As they are interested in getting as many viewers as possible at lowest possible cost (to show advertising to), then it's not surprising that they've stuck with the biggest transmitters.
Reception from Dover may be possible. I had a look down your road on Streetview and all the aerials I could see were on Dover. So you may be lucky and be able to receive the full complement of channels from Dover.
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Tuesday 3 July 2012 1:48PM
Nick: The full list of Freeview services by multiplex are here (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations