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Local DAB Build Out |
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#26 |
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Join Date: Jan 2002
Location: South East England
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The only viable local radio FM signal in Bridport is Wessex FM's relay from the Tx there.
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#27 |
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Join Date: May 2004
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I'm somewhat surprised the Gloucestershire MUX is completely absent from this listing - IIRC from the earlier maps, there were quite a few additional sites planned for the Cotswold valleys and the Forest of Dean.
Of course, those are the areas where BBC Radio Gloucestershire (uniquely I think) re-opened AM services because FM was poor, and this plan is about adopting FM equivalence... http://downloads.bbc.co.uk/abouttheb...dproposals.pdf Quote:
Subject to further technical analysis, across the http://www.bbc.co.uk/news/world-euro...rnsey-12932345UK the stations which BBC management would expect to continue to transmit in Medium Wave include Radio 5 Live, BBC Asian Network, BBC Radio Jersey, BBC Radio Guernsey, BBC Gloucester, BBC Derby, Radio Scotland, Radio Wales and Radio Ulster/Foyle Quote:
Guernsey, Alderney, Sark and Herm are not due to receive these stations via digital radio during the current charter period, which runs until 2017.
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#28 |
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Join Date: Apr 2001
Location: West Sussex / Surrey, UK.
Posts: 860
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I'm also surprised about the lack of London mux improvements considering it was a bit more in depth than that on the first report that was published which also included coverage maps in...2011?
Having said that it did sound as though the extra transmitters and work for London were the last phase (Phase 3) which probably won't be published in a detailed listing such as this at the moment. I mean, that's enough to be getting on with there. London will require works, at least for London III as this is required for Sussex. Unless they have switched Sussex to 10B instead of London III which was planned, but I'd be surprised given planning with neighbouring multiplexes. The document does say that the list is not definitive and final. That some additional works may take place given subsequent spectrum analysis etc. Therefore that doesn't rule out changes to London. Time will tell, in the next 18 months. |
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#29 |
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Join Date: Dec 2003
Location: South Dorset
Posts: 946
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Interesting to see they're putting the Bournemouth mux on Bincombe. I'd always thought a new mux would be created for Weymouth and Dorchester, but it seems not. (Maybe I missed an announcement.)
I wonder where that leaves Wessex FM. |
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#30 |
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Join Date: Mar 2000
Posts: 6,108
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It seems a bit ridiculous that Wirral is not included in the BBC expansion. It would probably be served ok with St John's Beacon but the BBC National is the ONLY one that is not due to be on this transmitter.
As a result, we will still have almost non existent and blotchy reception in Birkenhead which gets part signal from Moel Y Parc and part from Winter Hill. The centre of Birkenhead is slap bang in between and is not covered properly. |
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#31 |
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Join Date: Dec 2003
Location: South Dorset
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Having said that, isn't everywhere west of Abbotsbury considered to be the Exeter/Torbay mux area, but nothing mentioned for W Dorset for that either.
http://www.ofcom.org.uk/static/radio...d%20Torbay.pdf
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#32 |
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Join Date: Dec 2003
Location: South Dorset
Posts: 946
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Why on earth is North Hessary Tor being added for Cornwall?!
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#33 |
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Join Date: Jan 2004
Location: Lancs
Posts: 7,928
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#34 |
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Join Date: Apr 2011
Location: Future EU Scottish Republic
Posts: 820
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Thanks, but that is the one I used. What is the advantage of dbw over watts and kilowatts, or is it just a new ISO standard?
Sure you can start out from a quoted value in Watts, but you're never quite sure whether the bloke doing the quoting has remembered to add the TX forward gain to get ERP, or whether that's just the power at the end of the feeder. Using dBW makes it unambiguous, and in any case to do anything with a value in Watts you have to convert it to a log at some stage anyway. |
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#35 |
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Join Date: Jan 2004
Location: Lancs
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The advantage is that when you quote a dBW (or dBm for dB relative to 1 milliWatt for my profession, cellular) then if you have the antenna horizontal radiation pattern available e.g. via Ofcom's TX txparams, and know your bearing relative to the TX, you can very quickly calculate the dBW power value radiated in your direction via a direct subtraction. The quoted dBW values will be peak forward power, i.e. at the maximum forward gain orientation of the transmitting antenna.
Sure you can start out from a quoted value in Watts, but you're never quite sure whether the bloke doing the quoting has remembered to add the TX forward gain to get ERP, or whether that's just the power at the end of the feeder. Using dBW makes it unambiguous, and in any case to do anything with a value in Watts you have to convert it to a log at some stage anyway. Anyway looking at that that list I should get a good signal from Llangollen (really strong on FM here) and maybe the Liverpool service from Winter Hill. So a bit more choice. |
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#36 |
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Join Date: Dec 2005
Posts: 494
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Although Manchester gets a couple more transmitters nothing is being done about the fact that since the closure of the Regional multiplex transmitters the Manchester Multiplex is full to burst, surely a second local Multiplex would be of more value to a large catchment area.
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#37 |
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Join Date: Oct 2004
Posts: 14,633
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Why on earth is North Hessary Tor being added for Cornwall?!
(do these new transmitters relay from an existing one and not get their own feed? Perhaps they're doing Cornwall because it is transmitted from Caradon Hill and is a lot easier to receive than Plympton for Plymouth? totally uninformed speculation, of course) Interesting to see that a good number of relays are planned for Cornwall though. I've never had any complaints about the reception (even in car) but I live within LOS of Caradon Hill anyway (and can get Plymouth with a good aerial) |
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#38 |
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Join Date: Sep 2010
Location: Chelmsford, Essex
Posts: 323
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Essex to get a boost. Yes! ☺ The local DAB is shocking in Central Essex and Chelmsford. The modification on Bakers Wood and the addition of Great Braxted will be brilliant. Also, where is Whestley Heights, one of the new transmitters?
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#39 |
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Join Date: Nov 2012
Posts: 226
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In parts of Cornwall North Hessary Tor transmitter is a better signal than the Caradon Hill. Places like West Looe where the Caradon Hill transmitter is behind the hills and Plymouth and North Hessary Tor looking towards Devon is straight across the water!
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#40 |
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Join Date: Jan 2002
Location: South East England
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(do these new transmitters relay from an existing one and not get their own feed? Perhaps they're doing Cornwall because it is transmitted from Caradon Hill and is a lot easier to receive than Plympton for Plymouth? totally uninformed speculation, of course)
Even if they're on a different channel, there'd be adjacent channel interference to some degree. |
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#41 |
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Join Date: Apr 2001
Location: West Sussex / Surrey, UK.
Posts: 860
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Transmitters are either line fed or satellite fed.
Timing is critical though, with the use of GPS to ensure consistency. If timing is out on one tx, it'll punch a massive hole in coverage. I can't see how relays could work with DAB but I'm not an engineer. |
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#42 |
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Join Date: Jul 2014
Location: North Britain
Posts: 145
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Now that I have digital radio in the car it's amazing the amount of time it drops out whilst driving around locally in falkirk area. Still not up to the standard you'd expect
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#43 |
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Join Date: Dec 2001
Location: Hampshire
Posts: 8,076
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I can't see how relays could work with DAB but I'm not an engineer.
in anger ? http://downloads.bbc.co.uk/rd/pubs/w...les/WHP120.pdf |
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#44 |
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Join Date: May 2004
Posts: 13,569
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Now that I have digital radio in the car it's amazing the amount of time it drops out whilst driving around locally in falkirk area. Still not up to the standard you'd expect
Quote:
Coverage will be boosted in line with the equivalent FM coverage of each area's largest commercial radio operator.
Coverage will increase from an average of 72% to 90% (in some areas more, others less). But some DAB sites will not go live until a radio DSO is announced, the target is 50% listening and is currently at 38% so may be some time yet. (Unless Suzi Perry's radio ads made a big switch?)Quote:
In the event that the Government announces a digital radio switchover date, additional local DAB transmitters will be launched within 12 months of the switchover date, further boosting coverage.
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#45 |
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Join Date: Sep 2010
Posts: 4,475
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Quote:
http://www.a516digital.com/2015/01/a...adio.html#more
Coverage will increase from an average of 72% to 90% (in some areas more, others less). But some DAB sites will not go live until a radio DSO is announced, the target is 50% listening and is currently at 38% so may be some time yet. (Unless Suzi Perry's radio ads made a big switch?) http://www.theguardian.com/media/201...witch-hit-poor |
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#46 |
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Join Date: May 2004
Posts: 13,569
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There could be some objections to making it 75% especially set makers ( but many may agree)
I expect some BBC, Bauer and Global local stations and Absolute will soon close on AM, R4 LW 2020 and a FM switch off target date of large stations maybe 2022 assuming digital radio listening continues to grow slowly? |
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#47 |
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Join Date: Oct 2004
Posts: 14,633
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Quote:
My understanding is that it would be incredibly difficult to have DAB relays (other than in-shop ones) if they're operating on the same channel. There'd be the major issue of the output aerial feeding signal back into the input aerial in an endless loop.
Even if they're on a different channel, there'd be adjacent channel interference to some degree. Quote:
Transmitters are either line fed or satellite fed.
Timing is critical though, with the use of GPS to ensure consistency. If timing is out on one tx, it'll punch a massive hole in coverage. I can't see how relays could work with DAB but I'm not an engineer. Similar bodges have happened, for example Barnstaple/North Devon which doesn't get its own mux, but simply what was the Exeter and Torbay multiplex |
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#48 |
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Join Date: Apr 2011
Location: Future EU Scottish Republic
Posts: 820
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Quote:
Essex to get a boost. Yes! ☺ The local DAB is shocking in Central Essex and Chelmsford. The modification on Bakers Wood and the addition of Great Braxted will be brilliant. Also, where is Whestley Heights, one of the new transmitters?
Great Braxted will help enormously, not just locally but all over central Essex and down into the Dengie peninsula. Depending on what the 'DB' is relative to, the transmit array 'STAGGERED_DIPOLES_13DB' is at least 6 co-phased dipoles. Such an antenna is an enormous beastie at the Band III wavelength of 1.5m, probably about 6 to 7m in length, and will have to be delivered to site and erected as a unit due to the critical length cabling - no mean feat. Quote:
The BBC conducted tests for an 'on channel' DAB relay at Mapperley Ridge about 10 years ago. It's all rather tricky to set up and align, and I don't think it has ever been used in anger ? http://downloads.bbc.co.uk/rd/pubs/w...les/WHP120.pdf
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#49 |
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Join Date: Dec 2001
Location: Hampshire
Posts: 8,076
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Quote:
Hmm maybe. Perhaps getting the necessary leased line to NHT is expensive/hard (it's somewhat remote and currently only really does BBC FM plus a tiny TV relay) but they can send the Cornwall mux to it over microwave, or something (as NHT and Caradon Hill have line of sight, if I remember correctly)? Again, total speculation.
line of sight with each other. I suspect NHT will simply be fed by microwave from Caradon. On the subject of the South Hampshire mux, there was one proposal to use Hannington, to give a nice solid lump of coverage along the A303 corridor. It would also have served out of area Basingstoke, and actually a big chunk of North Hampshire, so presumably abandoned due to that being the N Hants/Berks area. A pity, it would have been nice to have the S Hants mux here in Basingstoke
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#50 |
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Join Date: Dec 2001
Location: Hampshire
Posts: 8,076
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Quote:
Not a relay as such, I don't think. I believe there are split ads on that frequency.
), And I've just remembered there's an audio delay between that and Bincombe Hill when the RDS flips between the two.
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), And I've just remembered there's an audio delay between that and Bincombe Hill when the RDS flips between the two.