The Ten Myths of DAB

[Don Petter]

As Bryn has pointed out, a good external aerial should get rid of such ghosting.

[Resurrection Man]

.... I find both FM and DAB offer enjoyable listening within their limits (principally in dynamic range in the case of FM, and in tonal quality where DAB is concerned).

.....

That is intriguing, Bryn. There is a thread going on over on avforums where some folks argue the opposite. Not saying you're wrong...just goes to show how subjective it all is. And what radio channel one is listening to. One bloke even said how fantastic DAB was on Radio 4 .....that the dynamic range was better than FM. What dynamic range?

[Resurrection Man]

As Bryn has pointed out, a good external aerial should get rid of such ghosting.

True. At the end of the day it comes down to a lottery. There are folks today who get a good FM signal with a simple transistor radio. Maybe the RF sections were better then. After all, in those days that is all that the designer had to provide for the money. Now it's iPod this and iPhone that 'functionality'. So the RF section gets socked.

So the situation as I see it is this.

Today

1) Some people get a good FM signal
2) Some people do not get a good FM signal. Option is to go for (3)
3) Some people get a good DAB signal
4) Some people do not get a good DAB signal. Option is to go for (1)

"Tomorrow" - after they switch off FM

1) No radio. They go out and waste some money and might get a good signal or they might end up in (4)
2) No change...they might have already gone to (3) or (4)
3) No change
4) No radio. A few more people might get a DAB signal but there will still be people who cannot.

And they call that progress ?
Switch off TM

[Eine Alpensinfonie]

That is intriguing, Bryn. There is a thread going on over on avforums where some folks argue the opposite. Not saying you're wrong...just goes to show how subjective it all is. And what radio channel one is listening to. One bloke even said how fantastic DAB was on Radio 4 .....that the dynamic range was better than FM. What dynamic range?

The dynamic range IS better on DAB - probably its only virtue.

[Bryn]

That is intriguing, Bryn. There is a thread going on over on avforums where some folks argue the opposite. Not saying you're wrong...just goes to show how subjective it all is. And what radio channel one is listening to. One bloke even said how fantastic DAB was on Radio 4 .....that the dynamic range was better than FM. What dynamic range?

I was, as I had hoped to be making clear, referring to the limited dynamic range offered by FM, and the limited tonal quality offered by DAB.

[Don Petter]

Perhaps I should have added a smiley.

[An_Inspector_Calls]

True. At the end of the day it comes down to a lottery. There are folks today who get a good FM signal with a simple transistor radio. Maybe the RF sections were better then. After all, in those days that is all that the designer had to provide for the money. Now it's iPod this and iPhone that 'functionality'. So the RF section gets socked.

That's far from the case. You only have to consider the developement that's gone into something like the RF front end in satellite LNBs to realise things have moved on considerably, and costs have fallen.

Just tried our one-and-only portable FM receiver inside the house. We're ten miles from a 100 kW transmitter but it's pretty hit-and-miss. You've got to have the aerial at the right vertical and horizontal angle, usually next to a window. And I remember my 'proper' FM reception into a high quality receiver, with an aerial as big as a bedstead on the roof. Beautiful birdies, without fail! Now, I just plug in a grotty Freeview receiver, shared with my DTT reception (<£50) and away you go.

And of course, there's the BBC HD stream for special occasions. On the latter, I think I've now solved my drop-out problem: convert to gigabit LAN, and avoild wireless connections.

As for DAB/(Freeview) benefits being confined to dynamic range, well there's also better signal to noise ratio, reduced distortion, bettere frequency response, better stereo separation - apart from that though . . .

[Eine Alpensinfonie]

Why on earth push a digital technology that many years out of date?
By all means push a decent technology.
But not DAB mp2.

[An_Inspector_Calls]

I agree mp2 is far from ideal, but in part the problem is not entirely the codec, it's also congestion caused by too many stations. If BBC R3 on DAB could manage 256 kbps, or even 320 kbps, there'd be no problem.

And against that, why on earth push for retention of a system that was designed in the 50s!

[Flosshilde]

As Bryn has pointed out, a good external aerial should get rid of such ghosting.

Do you mean an aerial on the roof, or wall? Unfortunately neither are really feasible.

[amateur51]

I agree mp2 is far from ideal, but in part the problem is not entirely the codec, it's also congestion caused by too many stations. If BBC R3 on DAB could manage 256 kbps, or even 320 kbps, there'd be no problem.

And against that, why on earth push for retention of a system that was designed in the 50s!

Perhaps because it's not what the consumers want?

I'm perfectly happy for DAB to go ahead if it's a workable propostion (which to me at the moment it isn't) but why do FM and LW have to go too? Millions of people have invested in FM radios in this country and it works for them. Why require them to buy new equipment and render their existing equipment useless at the same time. Anyone would think we were in a monopoly situation

PS: The recent posts on this thread really belong on the Techie section, I think Think of the non-techie readers please, boyz

[Resurrection Man]

Perhaps because it's not what the consumers want?

I'm perfectly happy for DAB to go ahead if it's a workable propostion (which to me at the moment it isn't) but why do FM and LW have tyo go too? Millions of people have invested in FM radios in this country and it works for them. Why requirre them to buy new equipments and render their existing equipment useless at the same time. ...

...

+ 1

Precisely my point and still no-one has given me a valid reason for forcing the FM switchoff.

[Resurrection Man]

That's far from the case. You only have to consider the developement that's gone into something like the RF front end in satellite LNBs to realise things have moved on considerably, and costs have fallen.

That's as may be but has no relevance to what has gone into a cheap DAB portable radio.

Just tried our one-and-only portable FM receiver inside the house. We're ten miles from a 100 kW transmitter but it's pretty hit-and-miss. You've got to have the aerial at the right vertical and horizontal angle, usually next to a window. And I remember my 'proper' FM reception into a high quality receiver, with an aerial as big as a bedstead on the roof. Beautiful birdies, without fail! Now, I just plug in a grotty Freeview receiver, shared with my DTT reception (<£50) and away you go.

Still no justification for switching off FM. Many millions of people are very happy with the FM signal that they get. Why should this be service be removed? Are they clamouring for DAB to be switched off instead? No. So why should the pro-DAB lobby be trying to force through the FM Switchoff?

And of course, there's the BBC HD stream for special occasions. On the latter, I think I've now solved my drop-out problem: convert to gigabit LAN, and avoild wireless connections.

Hardly relevant to the million or so transistor FM radio listeners

As for DAB/(Freeview) benefits being confined to dynamic range, well there's also better signal to noise ratio, reduced distortion, bettere frequency response, better stereo separation - apart from that though . . .

...and that fantastic low-bit rate enhanced fidelity, mud-burbling audio quality.

[Resurrection Man]

AIC...in post 11, you were remarkably patronising about some of the details on that website and I asked you for the unredacted report from PwC of which you must have a copy presumably to base your comments on. Any chance of a sight of this, please?

[An_Inspector_Calls]

AIC...in post 11, you were remarkably patronising about some of the details on that website and I asked you for the unredacted report from PwC of which you must have a copy presumably to base your comments on. Any chance of a sight of this, please?

My word, now post 11 has been both patronizing and supercillious. Just because I'm not talking to your hymn sheet. As for the PWC report, well considering you've asked so nicely in the past . . .

The example of LNB development I gave earlier is exactly to the point when countering your earlier suggestion that RF front ends have been neglected. They haven't, and in my view they've improved enormously and become cheaper in recent years. The fact that you can buy a quad receiver, operating betwee 10 and 12 GHz for about £50 is just mind-blowing.

The simplest justification for switching off FM is that the RF spectrum is a limited resource and we're transmitting most of the BBC radio channels on MW, FM, DAB, DTT, and satellite. That's profligate and more than adequate. Then throw in internet and 3G/4G. I would, however, resist LW going because I regard the LW transmission of R4 as a national security asset which we should not relinquish. You might counter by saying no one has come forth and made any proposals for the FM band, but why should industry do that for what might be a chimera? But I'd bet folding money that the adjacent aviation bands might well be extended (they're hugely congested at the moment) as would 4G-displaced frequency hoppers from the 866 MHz band. And another reason why analogue radio should go was my earlier, 'supercillious' point about the projected high revenue costs of maintaining the network, cited by PWC.