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local signal ranges on DAB much poorer than FM.
Bill Clinton
Posts: 9,389 Forum Member
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I have in car DAB now, and something I've certainly noticed is how much more limited the ranges on the local multiplexes in comparison to the FM signals. I have 5 local multiplexes that cover the North West preset, City on Liverpool Multiplex, Rock on Lancashire Multiplex and Key 103 on Manchester multiplex and in comparison to those stations on FM the range is incredibly more limited. Eg I can easily listen to 97.4 Rock FM all over the Wirral but to do the same on its DAB signal you can only just about pick it up in a couple of high spots such as in Heswall and along the front at New Brighton. City 96.7 on FM penetrates deep into North Wales but the same cannot be said for its DAB signal although I did get it up the Great Orme where I also got Lancashire and even Manchester, I can't remember if I got Stoke & Stafford up there but I think I did. Signal 1's another one, it has a hell of a signal on 102.6 but the Stoke & Stafford mux barely gets past Kelsall Hill coming back towards Chester, and there's only a few select places on the Wirral it comes in. The Manchester mux and therefore Key 103 on DAB is dead after about Warrington, whilst it used to be possible to have James Stannage on FM all down the M56 and right into North Wales when he was still at the station. The only big exception to this in the North West is Dee on DAB, which in comparison to Dee's 106.3 signal from the city of Chester itself has a pretty huge signal on DAB.
Could the plan be to make stations much more local when it comes to DAB? because on DAB they stick to their patch which they are meant to be serving so much more, and then with networking the overlap would be far less noticed in an eventual FM free system.
At least for now, you can always listen to overlapping stations on FM, but in the future this may be switched off eventually and could lead to much more restricted ranges if DAB technology becomes the norm.
Apart from this, I'd easily prefer the DAB choice of stations over the FM only ranges, it's great having the extra stations from the BBC, and even getting access to things like Magic in car is much better than AM. Shame Global don't seem keen on it, I enjoyed for some reason having Heart London & LBC before they closed, now in this area.
Are local DAB multiplexes deliberately less powerful than FM counterparts or is it just the nature of the technology which goes to dropouts at the slightest hint of a bad signal? Obviously with FM a good car radio can stick with a signal to the bitter end, long after DAB would have dropped out, hence some of the amazing ranges, such as enjoying 97.4 Rock FM all the way to Bangor in North Wales.
Could the plan be to make stations much more local when it comes to DAB? because on DAB they stick to their patch which they are meant to be serving so much more, and then with networking the overlap would be far less noticed in an eventual FM free system.
At least for now, you can always listen to overlapping stations on FM, but in the future this may be switched off eventually and could lead to much more restricted ranges if DAB technology becomes the norm.
Apart from this, I'd easily prefer the DAB choice of stations over the FM only ranges, it's great having the extra stations from the BBC, and even getting access to things like Magic in car is much better than AM. Shame Global don't seem keen on it, I enjoyed for some reason having Heart London & LBC before they closed, now in this area.
Are local DAB multiplexes deliberately less powerful than FM counterparts or is it just the nature of the technology which goes to dropouts at the slightest hint of a bad signal? Obviously with FM a good car radio can stick with a signal to the bitter end, long after DAB would have dropped out, hence some of the amazing ranges, such as enjoying 97.4 Rock FM all the way to Bangor in North Wales.
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I would say D1 and BBC compare well to their national FM counterparts though.
I believe it is a little better now, but still needs improvements.
Also, DAB can be affected by hills more so than FM.
The Reigate DAB for the new Surrey mux covers a significant area, but Oxted only a few miles away receives nothing at all.
But, going south, it reaches beyond Horsham towards the south downs.
Obviously hills can block a Band III signal more than Band II but on the other hand DAB on Band III will often 'bounce' and give perfect reception when VHF/FM on Band II will be very distorted from multi-path. Some friends of mine and not far from the local Band II transmitter but there were having to fiddle with the antenna every time anyone moved. I told them them about DAB being available and they found reception is perfect even though the transmitter is slightly further away and also blocked by a nearby hill.
I've found that the London Muxes seem to pretty much mirror the FM London stations in the Sussex area. I often drive down to the coast and can listen to Kiss and Capital on FM (from Croydon) or DAB (assume Reigate/Guildford or Wrotham)all the way to the south downs if I go to Worthing/Littlehampton. If I go to Shoreham again it cuts out in the hills, but I've actually picked it up on the seafront there (I think that's more to do with the Shoreham gap where the hills drop giving a path all the way to the north downs where Reigate is).
The new Surrey Mux is similar, but a tad weaker and the Sussex Mux is pretty much useless in Horsham, but it only has tx's along the coast and shares its frequency with London 3 which booms in, so blocks the Sussex one. I imagine if either London 3 or Sussex changed frequency, the coverage would be better.
This is the case where I come from. The FM transmitter is 250kW per BBC national station and it's only about 8 miles away, but the reception is so bad it's impossible to make out what anyone's saying. DAB from the same location is only 10kW for the whole BBC national multiplex but reception is rock solid. A few years ago they added another DAB transmitter in the area so this is no longer a fair comparison, but for many years it was.
As for multipath distortion on FM I have one portable radio and both car radios which cope really well but the vast majority of FM radios are just useless in areas where multipath is a problem. Perhaps set makers should take a closer look at this problem.
Unfortunately it is a 'feature' of FM, I suppose theoretically you could reduce the problem with several antenna on the car and a diversity system! I saw the amount of work that was done on one site to reduce multipath on a fixed installation, it needed a lot of work and cost a lot. Diversity also reduces mobile flutter.
They need to sort something out with the online football rights before they switch off FM.
I live in Manchester, but because of where I grew up I support Everton,and listen to Radio Merseyside's football comms every week on FM - online is no good, you just get the message about the rights for 2 hours.
On DAB, the only local football coverage I'd get would be Manchester's! >:(
There's loads of Evertonians and LFC fans in North Wales, who can't get to the games, and enjoy the commentaries on BBC Merseyside, yet on DAB, what would they get? Radio Wales commentating on Cardiff and Swansea!
I imagine there's going to be equally bad trouble in the south - how many fans must clubs like Spurs or Chelsea have in Berkshire, for instance, yet they'd only be able to hear comms of Reading on their own BBC local.
When Tune In makes radio so easy on your phone, it's a real pain to log into a club site to try and get commentary, and often they actually charge you for membership! On FM, I listened to a Tranmere commentary that weekend there were no Prem games, but I'm not going to pay a year's membership to their Player service to hear something that should be free!
EDIT: To anticipate a couple of answers. a) "These games are on Sky anyway" - not at 3pm on a Saturday, and I can't be the only person who doesn't have Sky/BT Sport. b) "Premier League commentaries are on 5Live/Talksport" - not with the local summarisers who are experts on a particular club. Ronny Goodlass has far more of interest to say on Everton, watching us live every match, than Danny Mills or John Hartson wandering in every three or four weeks or so.
BBC Radio Merseyside's editorial coverage area does not include North Wales, so no one living there should have any expectation that they'll be able to pick up the station now, or be able to do so in the future. Any reception they can get should be considered a bonus, not a guarantee. When Radio Merseyside's AM transmitter was switched off as a trial, most of the complaints they got were from listeners in North Wales, outside of their coverage area.
In the case of BBC London, the DAB signal covers a large part of the home counties, at least as much as FM, if not more. In Surrey, DAB reception is much better than FM due to the use of the local transmitters.
The North West multiplexes really are useless - no overlap between them - right next to the Winter Hill transmitter with clear LoS there is no signal from Manchester or Central Lancashire, and even within Central Lancs the multiplex drops out too often - even with Winter Hill visible (even more galling when Rock FM comes in throughout most of the North West clear as a bell).. While it's understandable they want to optimise coverage to reduce overlap some overlap is beneficial, especially in car (the constant retuning between Nottingham and Leicester while heading towards Loughborough or Nottingham and Yorkshire while in North Notts heading down the A614 does get annoying after a while). Hopefully the transmitter build out will fix most of these gaps!
Some of the earlier multiplexes (Lancashire, Leicestershire) have drawn the short straw in terms of coverage - the later ones tend to be better (it's not often Nottingham drops out in the county south of the Retford/Worksop area).
Chiltern Radio for Bedford on the other hand started broadcasts in 1981 and this came in in clear mono at my home, 45 miles away on the FM frequency broadcast from a very high mast at Sandy Heath.
I've got a Pure Move 2500 and scanned that on top of the multi-story as a test and also got Cambridge & Kent MUX's.
I'd say I get a better DAB signal here than I do FM.
And some of the FM locals are, or were, overpowered. I can't really think of a good reason why BBC Radio Bristol should have been audible from north of Gloucester down to Exeter, and from Swansea to the borders of Berkshire (whilst being frustratingly hard to get in Bristol itself).
http://stakeholders.ofcom.org.uk/broadcasting/radio/coverage/dab-coverage/annex-b
The Mou will sort out the funding? but no timescales yet?
Do you think North Wales is well served by having Radio Wales as its 'local' BBC station?
From the bits I've heard, it's very South Wales-centric, particularly sport, so I think the BBC should look very hard at the 'local' radio service it would provide for the area on DAB. The fact that these complaints about Merseyside's AM came from North Wales should tell you everything you need to know about the service Radio Wales is giving these listeners.
It's almost a stereotype that Radio Manchester has 'Manchester Music' on a Saturday night. "Ah right, tonight's guest is BONEHEAD, top, sorr-ed, quali-eh".
Do the BBC assume this automatically appeals to everybody living in the Radio Manchester area and yet nobody outside it?
Same with the soul programmes on Radio Lancashire and Sheffield... the Lancashire one in particular I wouldn't be surprised to hear has as many FM listeners in Manchester as 'Manchester Music', just from an older generation. The guy reads several texts and emails from Manchester (and Liverpool) anyway.
Does anyone on here have any idea if that's correct? I knew it must be at least a bit more expensive (more sites = more rent / more maintenance costs, more equipment to buy), but didn't think it would be quite that expensive.