DAB Radio?

[doug748]

I have zero knowledge about radio, but am an avid listener and, of course, value the broadcast weather info. Can anyone supply a laymans explanation of digital radio? How can it spring fully formed into the world when all the frequencies are already allocated, what is the future of analogue, etc? Also, the key question, is it any good? It seems to me that battery life is so poor as to make it all but useless for small, portable sets. Any medium which is not pretty solid is of questionable value; I recall we were all told that domestic FM was to be a great step forward....and what a load of old junk that is.

 

[Sailfree]

Sorry can't answer all your questions but SWMBO thought we could not live without DAB. Bought 2 expensive quality DAB's and they both worble and distort on speech (listen a lot to Radio 4). But then Southampton is in the wilderness so why should we expect them to work!!

 

[neilmcc]

First got DAB two years ago but was dissapointed with it due to poor signal and I still got a better sound with FM.
In the last couple of months there has obviously been another digital transmitter switched on and it now works very well. All channels crisp and clear and loads to choose from. Radio channels from Lands end to J o'G (mostly rubbish but it's the thought that counts)
So as long as you have access to a good digital signal it should be better than your old analogue set.

 

[gtuson]

We have DAB in emsworth. Good signal - although not so good on steel hulled boat. But there is big issue about battery life as you mention. it does not get mention in the publicity - our small portable DAB, with half as many batterries again as analogue equivalent has to be charged up more or less daily....and i thought we were meant to be cutting down on electricity. Does Digital TV use more power than analogue? By how much, if so?

 

[tangofour]

The radio signal carries 1's and 0's that build up words that digitally represent the audio waveform that the audio section should reproduce.

Why so heavy on batteries? the descriminator section of an old analog radio produces a signal that simply needs amplifying to produce an audible output. With Digital you basically have to have a 'computer' in line with the 1's and 0's to rebuild the signal, even with ASIC's ( specialised IC's ) these things need regulated, smoothed and accurate power and that in itself takes power!

The theory is that you can do error correction on the digital signal stream and it is actually easier to recover digital information from noisy signals than it is to get clean analog since you are looking for just 2 levels. It all takes processing and therefore electrical power however.

What the corporate types dont care too much about is those people who would rather have a somewhat crackly and indistinct analog signal to an all or nothing digital signal.

With the current digital 'revolution' you are pretty much guaranteed that radio will move permanently to this format, same as TV.

There is a fair amount of resistance however but like CD's it will happen.


Digital TV's have matched the migration to LCD's of the display section so the overall power consumption has probably dropped. The receiver section consumption has however probably gone up markedly.

 

[Chris_Robb]

I have both DAB and Analogue. I cannot conceive to having to listen to radio 3 on DAB as the KBPS is only 198 compared to a CD of 400 odd. A good arial on a VHF will always provide better sound than DAB. Scandinavia have dropped the DAB standard as old technology ( old compression system) and are doing something else! Oh well Same goes for MP3 on classial music - just not good enough!

 

[mobeydick]

DAB can could be good quality, but nearly all stations use less bps than equivalent FM station. Most other counties are going with DAB+ or other approaches, and I believe even the BBC will be broadcasting on both DAB and DAB+ sometime in the future. I think DAB is maybe a dead end.

AM radio you could pick up with an earphone and no external power at all. FM needed more power but better quality. DAB needs yet more receiver power and allows more channels.

 

[oldharry]

DAB is claimed to be intereference free. It is, it just disappears altogether if the signal downgrades at all.

Bloomin useless IMHO!

Bought a DAB set for SWMBO for christmas, as she was taken in by all the wonderful claims made for it.

Its gathering dust now, and she has gone back to the 'old' Fm set. She reckoned the sound was worse (true), it kept switching off (signal fade), she couldnt work out how to tune it (and shes quite good on PCs), and she just couldnt be bothered.

 

[doug748]

Just as I suspected. Another stitch up!

 

[rickp]

Shame everyone seems so negative, as I love my DAB set. It records the shipping forecast each morning without disturbing me - so I can listen to it when I wake up. It records all my favourite Radio 4 comedies and stuff from BBC7 during the week, so I am never without things to listen to when I'm on the boat.

On our trip west a few weeks ago, we had a DAB signal at Scilly, Falmouth, Fowey, Plymouth, the Yealm, Dittisham (though not Dartmouth oddly) and also had no problems around the Solent and Weymouth, Lulworth, Swanage etc. Admittedly I do have a decent aerial, but its only lent against a cupboard in my cabin - not mounted up high anywhere.

I take the points on power consumption, lack of graceful degredation. Sound quality-wise it may not match my 'hifi' at home, its perfectly acceptable for on the boat.

Cheers,
Rick

 

[jhughes]

What radio have you got, the capability to autorecord sounds like a good idea.

 

[ChasB]

Agreed, but DAB implementation in this country is very disappointing. take a look at this page (so how come Estonia has got the best system in the world? /forums/images/graemlins/confused.gif ) And have you ever wondered why you never see a stereo DAB set? That's cos it's mono.

Still, you can pick up a set cheap from places like Lidl or Richer Sounds, but I'd stick with FM till things improve.

 

[ChasB]

plus...

"The DAB system has recently adopted the new AAC+ audio codec, and existing stations that use the old MP2 format will probably be switched off completely in the UK in around 7-8 years' time. More to the point, however, DAB radios being sold in the shops today will not be able to receive any of the many new stations that will launch using the new AAC+ format in the coming years"

Funny how they don't mention that in the shops.

 

[rickp]

I guess thats not mentioned because neither OFCOM nor the BBC have said there are any plans to move to the AAC+ codec. Of course, that doesn't mean they never will - so its great for the nay-sayers...

Of course, the MP2 codec degrades somewhat better than the AAC+ codec but you can't please everyone (or even, anyone at all, it seems).

Rick

 

[ShipsWoofy]

[ QUOTE ]
I guess thats not mentioned because neither OFCOM nor the BBC have said there are any plans to move to the AAC+ codec. Of course, that doesn't mean they never will - so its great for the nay-sayers...

Of course, the MP2 codec degrades somewhat better than the AAC+ codec but you can't please everyone (or even, anyone at all, it seems).

Rick

[/ QUOTE ]

Shirley if it is just a codec then a firmware upgrade will fix most if not all radio / tv receivers (dab content) and PC type listening devices?

<span class="small">**Disclaimer - This is not a critique, nor a comment on your statement, it is a genuine question, especially as I am quite close to buying the add-on to my JVC stereo in order that I can pick up DAB on the boat.** </span>

 

[oldgit]

Have a listen for yourself.

Have DAB on boat,in the car and at home,the sheer variety of stations is more than a counter balance to any alleged shortcomings in the audio quality.
The blessed relief of not having to listen to the dire outpourings of tedium laced with a deadly drip drip of double glazing and mobile phone ads normally available on FM is bliss.
Having actually compared R3 side by side on DAB and FM via a Linn system,suspect that on most listeners equipment the "difference "is only discernable by those with very very "Golden Ears",buy it and try it .The output from most of the transmitters is very very low at the moment but will be increased in the near future as will the number of sites.Sets are available from around £30 pounds,somewhat less than a tank of petrol and so what if they change the format,throw it away,how many out there are still using their VHS or Betamax recorders.?All gone CD we hope.
(Please dont answer that) /forums/images/graemlins/smile.gif

 

[lenseman]

[ QUOTE ]
SWMBO thought we could not live without DAB. Bought 2 expensive quality DAB's and they both worble and distort on speech (listen a lot to Radio 4).

[/ QUOTE ]

Interested in the fact that you also suffered the same fault that I did with a DAB installation. Firstly, I assume you have an aerial installed and that it is VERTICALLY polarised, not horizontal like the VHF antennas.

When I suffered the distortion, I installed a folded dipole vertically polarised but it did not cure the warbling and distortion that you mention so I conducted further tests.

I found that the mains supply voltage was fluctuating and that the warbling and distortion started when the supply volts to the receiver dropped to 219 volts and got steadily worst until the mains voltage dropped to 213 volts by which time the DAB receiver stopped altogether.

Of course, you might have a battery supply but the DAB processing will gobble batteries so you must be very rich /forums/images/graemlins/grin.gif

If you are on mains supply to the DAB receiver, monitor the mains supply voltage and note the voltage when the faults appear? Let me know the results.

 

[kcrane]

We have two Pure sets at home (Cheltenham) and they work fine. To my ears the quality is good. They're used for Radio 4 & Virgin. On the boat (Gosport) we have the newer 'splash proof" rechargeable one, and again, it works well using its built in aerial.

 

[oldharry]

Sound quality actually has very little to do with the actual means of transmission, and on a good Hi Fi the only discernible difference between FM and DAB is a marginal reduction in SN ratio.

A good quality FM set will sound better than a cheap quality DAB set - and vice versa.

I rather fail to see the point of buying a DAB set with a poor quality audio stage and mini speaker in it. This I think is why SWMBO has gone back to her FM set - it is actually a very good little table top set, while the DAB christmas present was a smaller portable one with inferior sound quality.

Doesn't matter how good the sound source is, a cheap audio stage and speaker will mangle it!

But I still think its a waste of time as it stands in this country, and the sound quality is definitely inferior to the digital Satellite signal provided by Sky.