Jim Lesurf wrote:

Which 'specs' are you referring to?

Bandwidth, IIRC the top end cuts off at higher frequencies in FM than DAB.

But having a bath with a yagi is probally not practical.


--
http://www.petezilla.co.uk

In article , Peter Chant
wrote:
Jim Lesurf wrote:

Which 'specs' are you referring to?

Bandwidth, IIRC the top end cuts off at higher frequencies in FM than
DAB.

Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded that.
It does use a 48k sampling rate so in principle could reach 24kHz, although
I assume the data-reduction will throw away some of the HF end depending on
settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I should
check.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , Dave Plowman (News)
scribeth thus
In article ,
tony sayer wrote:
If thats all you need and the claimed perfick DAB reception isn't up to
it then why bother with DAB?. If you follow most any DAB forum apart
from poor audio quality, OK not that much of a problem for a bathroom
radio, the biggest gripe is power consumption and hence battery life!..

R3 uses a higher data rate than any other and is likely to sound just
fine. As will R4 being mainly speech.
I also wonder just how many would notice the other stations low data rate
on a portable. My guess is very, very few. Especially in a blind test. ;-)


Thats about all its good for portable listening, provided you've got the
battery belt to go with it;!...
--
Tony Sayer

In article , Andrew
Haley scribeth thus
Gordon MacPherson wrote:

Looking for a DAB radio to leave in the bathroom! Main problem is
reception - it seems to be a weak signal - so sensitivity is an
issue. Also must run on batteries so battery life is a
consideration. Does not need any fancy features - radios 3 and 4!

Pure Oasis. Cracking piece of kit: showerproof, damn loud (important
in a shower) and decent battery life. There's a new version, the
Oasis Flow, that has analogue radio too. I find the reception
execellent, but I'm in Cambridge which has middling DAB signal
strength.

Andrew.

Well Cambridge has according to Arqiva and the BBC excellent strength a
mix of Band 3 mitters from Madingley up to 5 kW !..

--
Tony Sayer

Jim Lesurf wrote:


Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded that.
It does use a 48k sampling rate so in principle could reach 24kHz,
although I assume the data-reduction will throw away some of the HF end
depending on settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I
should check.

I've not read it for a while but I through FM was 17.5 - 18 kHz whereas DAB
was 16kHz - though I probally saw this spec nearly 20 years ago. Googling
now mainly brings up items such as critism of compression. Wikipedia says
15kHz, but I'm sure it was a bit higher. Suppose it depends on how close
you allow yourself to get to the 19kHz pilot tone.

However, I suspect _working_ DAB would beat average FM for sound quality -
i.e. where the user is not too interested to make the effort / cannot get
good reception, not that I've tried.

Pete


--
http://www.petezilla.co.uk

In article , Peter Chant
scribeth thus
Jim Lesurf wrote:


Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded that.
It does use a 48k sampling rate so in principle could reach 24kHz,
although I assume the data-reduction will throw away some of the HF end
depending on settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I
should check.

I've not read it for a while but I through FM was 17.5 - 18 kHz

Its cut off at 15 kHz in most all systems to protect the pilot tone at
19 kHz..


whereas DAB
was 16kHz - though I probally saw this spec nearly 20 years ago. Googling
now mainly brings up items such as critism of compression. Wikipedia says
15kHz, but I'm sure it was a bit higher. Suppose it depends on how close
you allow yourself to get to the 19kHz pilot tone.

However, I suspect _working_ DAB would beat average FM for sound quality -
i.e. where the user is not too interested to make the effort / cannot get
good reception, not that I've tried.

Well how many bits do you want to specify?...


Pete



--
Tony Sayer

On Fri, 6 Aug 2010 20:48:21 +0100, tony sayer
wrote:

In article , Peter Chant
scribeth thus
Jim Lesurf wrote:


Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded that.
It does use a 48k sampling rate so in principle could reach 24kHz,
although I assume the data-reduction will throw away some of the HF end
depending on settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I
should check.

I've not read it for a while but I through FM was 17.5 - 18 kHz

Its cut off at 15 kHz in most all systems to protect the pilot tone at
19 kHz..


The low cutoff in FM is not so much to do with the pilot tone as the
fact that it is distributed to the transmitters using NICAM, which has
a 32kHz sampling rate.

d

In article , Don Pearce
scribeth thus
On Fri, 6 Aug 2010 20:48:21 +0100, tony sayer
wrote:

In article , Peter Chant
scribeth thus
Jim Lesurf wrote:


Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded that.
It does use a 48k sampling rate so in principle could reach 24kHz,
although I assume the data-reduction will throw away some of the HF end
depending on settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I
should check.

I've not read it for a while but I through FM was 17.5 - 18 kHz

Its cut off at 15 kHz in most all systems to protect the pilot tone at
19 kHz..


The low cutoff in FM is not so much to do with the pilot tone as the
fact that it is distributed to the transmitters using NICAM, which has
a 32kHz sampling rate.

d

Don do bear in mind that the BBC isn't the only broadcaster in the UK and not
all use NICAM feeds;!.

Also FM stations elsewhere in the world aren't NICAM fed.. Usually line or
microwave radio link.

Still a couple of K up at that end aren't going to set the world alight;}..
--
Tony Sayer

On Fri, 6 Aug 2010 22:38:57 +0100, tony sayer
wrote:

Its cut off at 15 kHz in most all systems to protect the pilot tone at
19 kHz..


The low cutoff in FM is not so much to do with the pilot tone as the
fact that it is distributed to the transmitters using NICAM, which has
a 32kHz sampling rate.

d

Don do bear in mind that the BBC isn't the only broadcaster in the UK and not
all use NICAM feeds;!.


Let's have no words of sacrilege spoken here, please.

Also FM stations elsewhere in the world aren't NICAM fed.. Usually line or
microwave radio link.


The GPO used to supply lines to the BBC. They had not so much a
rolloff as a continual slope. I think the Beeb engineering department
designed equalizers, but of course there isn't an engineering
department any more.

Still a couple of K up at that end aren't going to set the world alight;}..

Not for me they aren't - not any more anyway.

d

In article , Don Pearce
wrote:
On Fri, 6 Aug 2010 20:48:21 +0100, tony sayer wrote:

In article , Peter Chant
scribeth thus
Jim Lesurf wrote:


Does it? Stereo FM is limited to about 15kHz. I thought DAB exceeded
that. It does use a 48k sampling rate so in principle could reach
24kHz, although I assume the data-reduction will throw away some of
the HF end depending on settings and content.

Where did you get the info? I've not measured DAB in ages. I guess I
should check.

I've not read it for a while but I through FM was 17.5 - 18 kHz

Its cut off at 15 kHz in most all systems to protect the pilot tone at
19 kHz..


The low cutoff in FM is not so much to do with the pilot tone as the
fact that it is distributed to the transmitters using NICAM, which has a
32kHz sampling rate.

I think this is a situation that have 'sort of evolved' over the years for
a variety of reasons. (Bit like AM on MW where bandwidths decades ago were
higher than nowdays.)

In days of yore with mono it seems likely that BBC FM could at times give
an audio bandwidth above 15kHz as there was no pilot tone, etc. However as
has been mentioned that was all at the mercy of the GPO landlines. So while
people getting Wrotham may have had good results, people up here in the
frozen North were likely to get something rather more limited, with added
noises, phase oddities, etc, etc.

Stereo complicated the issue, and IIRC that was when people decided to cut
the audio at 15kHz (ish) to give space for the 19kHz tone. Probably more
important then than now as the early decoders had to use simple tuned
circuits to isolate the 19kHz and double it to get the 38k subcarrier. So
any nearly audio could upset that quite easily. (Took a few years before
good PLL decoders were common and decoders became fairly resistance to
near-19k distractions.)

Then the BBC started using LPCM to get over the pest of GPO analogue
landlines. IIRC they used one system for a time before changing to NICAM,
and have probably changed details. But as has been said that pretty much
nailed a hard limit of 16kHz onto the system.

I don't know the current practical bandwidth for DAB broadcasts. Must
measure it unless someone knows of some recent results (?) In principle it
might be as high as 24 kHz. But the data reduction probably tends to
discard stuff above 15kHz (ish) as being 'inaudible' and prefers to give
the bits to lower frequency components with a higher priority.

FWIW Pure used to boast of a fancy 'technology' they had to 'improve' the
sound of DAB. Gave it a nice PR name I've forgotten. But when I asked them
to explain they never did... Odd that. :-)

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html