Petition to stop FM being switched off

Zero Tolerance wrote:
On Fri, 26 Jun 2009 16:28:11 +0100, Paul Martin
wrote:

With 128kbps MP2 being Joint (Intensity) Stereo, the stereo image of
some sound effects and atmosphere tends to be muddied. Applause is
particularly difficult to image. On the DSat feeds, JS and Discrete
Stereo are dynamically chosen by the encoder on a block-by-block basis,
but then there is a bit more leeway when you're encoding at 192kbps.

Could it ever be feasible for a multiplex of audio stations to be
dynamically statmuxed together?

Of course. Let's assume say UDP over IP over a radio channel. Or a
multicast IP protocol. With packets from all channels being time stamped
and queued..they go out when there are free slots.

The problem is graceful degradation...

Bill Wright wrote:
"automaticgaincontrol" wrote in
message
...
From most all of the comments I've heard from local shops and the few
people I've spoken to .. the main driver for DAB receiver purchase is to
receive Radio 5 Live better, where the medium wave reception is not that
good!..

Round here its fine .. well as far as MW goes, in the car...
--
Tony Sayer

Frankly though, who would really take 909/693 over DAB? Its such a
tough fatiguing listen even in daylight hours.

Oh really! When I was young AM was the only type of radio there was. We just
accepted the audio quality for what it was. Things like that are only
'fatiguing' if you let the quality wind you up. Just relax, say to yourself
'it's AM' and let the mellow sound wash over you.

When we were young there wasn't broadband trashing all over MW. nor so
many stations, and those were at pretty high power.


Bill

"The Natural Philosopher" wrote in message

Dave Higton wrote:
In message
"DAB sounds worse than FM" wrote:

Basically, if you understood the technologies that are used then
FM
basically can't be worse than DAB.

I /do/ understand the technologies involved. FM is worse than DAB
because all the decoders we use are non-linear, therefore FM
broadcasts, once received, are subject to intermodulation and
harmonic distortions. DAB isn't. It is very much like the vinyl
versus CD and valves versus transistors arguments.

Dave
Absolutely.

In all case people confuse comparisons between state of the art old
technology, and the very first of the new.

The very first transistor amps were pretty dire. Today's are pretty
cheap. If you spend enough on the circuitry - as much as you would
spend
on a valve amp - transistors are much BETTER. Particularly MOSFET
types.

Likewise early CD players. That suffered from non linear DACS. And
drifted with temperature too.

Now its DAB versus FM. Same applies. DAB will get better. If people
demand it.


No, it can't get better because they allocated all the spectrum in
2006, so all the spectrum available for DAB to use in the UK is
already in use apart from one channel that was going to be used for
the second national commercial multiplex that fell through last year.
Basically, the bit rates aren't going to go up, so the audio quality
can't go up either because DAB uses the MP2 audio codec that's around
20 years old, so it's been optimised to death already.

Take the BBC's national DAB multiplex for instance. The BBC has to
reduce Radio 4 to mono just to allow the part-time Radio 5 Sports
Extra station to go on-air - i.e. its multiplex is full to bursting,
so it would be impossible to increase the bit rates of the BBC's
stations, so the audio quailty is as good as it's going to get.

The *only* way to improve the quality on DAB is by switching to DAB+.



--
Steve - www.savefm.org - stop the BBC bullies switching off FM

www.digitalradiotech.co.uk - digital radio news & info

"It is the sheer volume of online audio content available via
internet-connected devices which terrifies the UK radio industry. I
believe that broadband-delivered radio will explode in the years to
come, offering very local, unregulated content, as well as opening a
window to the radio stations of the world." - from the Myers Report

Bill Wright wrote:
"Steve Terry" wrote in message
...
It's simple enough to calculate a 1/4 wave aerial
300 / F x 0.95 (velocity factor in a conductor) then / 4 for a
quarterwave.
So 300 / 226MHz = 1.3274 x 0.95 = 1.26106 / 4 = 0.31526m or 315mm

Presumably you're 'telling the audience'. I've been working out aerial
dimensions and building arrays since 1960. Here's a basic template I use for
BII aerials. It's based on practical experiment. This design matches 75ohm
cable and as long as the cable is taken off carefully a 75/75 balun does not
improve gain, although it does of course reduce pick up on the cable.
http://www.wrightsaerials.tv/ourwork...dimensions.pdf


Your 275mm is a bit short, just over a foot is more like it

Always best to work out the theory, then cut a bit long and do a practical
test, then repeat it about 20 times(!). Never believe theory. There are
factors other than the ones you list, such as the type of ground plane and
its angle to the dipole (not all groundplanes are flat and level; not all
are 'perfect'). The assumption of 95% for velocity factor is not good
enough. It varies quite a lot with material and diameter. Also an inclined
dipole (like the Blaupunct DAB one) will peak at a different length to an
upright one. The exact physical way the bottom of the quarterwave is
connected will have an effect.


Tell it like it is!

waving your hand NEAR a tune HF whip makes a huge difference..


Bill

tony sayer wrote:



Funny that but my wife is a bit too young for listening to the Archers
but shes critical of the sound of FM and low rate DAB!...


I'm glad that she appreciates the benefit of higher rate DAB!

regards, Ian

"The Natural Philosopher" wrote in message


Well FM given a sufficient signal, and remember too that DAB needs
a
sufficient signal to work properly, can be very good indeed. And
unlike
DAB where that is degraded due to the "cost of bits" FM degrades to
Mono
only because of the signal level.


I prefer a GOOD digital implementation, mostly because the common
problems with FM are because the signal is NOT good.


The BBC's Internet radio streams (launched last week) are using 128
and 192 kbps AAC - they're the best quality available on any of the
digtial platforms.


I suppose what I am saying is, whilst in theory an FM signal is
superior
to a bad DAB signal, the reality of MOST peoples experience is that
neither the signal strength, nor the quality of the receiving
equipment
is good enough to make that a fact in practice.


I really do disagree on both counts - I think there are tens of
millions of people with adequate FM reception quality, and IMO FM
devices (excluding DAB radios where the FM is deliberately screwed up
to help DAB) are pretty good on the whole - why are you excluding the
possibility for FM receivers have improved over time as technology
advanced?


With digits, the chipsets take all the hard work out of the quality:
you
get a predictable performance at far lower production costs.


But DAB is damaged at source, and no amount of electronics at the
receiver could ever hope to repair that damage.



--
Steve - www.savefm.org - stop the BBC bullies switching off FM

www.digitalradiotech.co.uk - digital radio news & info

"It is the sheer volume of online audio content available via
internet-connected devices which terrifies the UK radio industry. I
believe that broadband-delivered radio will explode in the years to
come, offering very local, unregulated content, as well as opening a
window to the radio stations of the world." - from the Myers Report

The Natural Philosopher wrote:

From most all of the comments I've heard from local shops and the few
people I've spoken to .. the main driver for DAB receiver purchase is to
receive Radio 5 Live better, where the medium wave reception is not that
good!..

Round here its fine .. well as far as MW goes, in the car...
--
Tony Sayer

Frankly though, who would really take 909/693 over DAB? Its such a
tough fatiguing listen even in daylight hours.

Oh really! When I was young AM was the only type of radio there was. We just accepted the audio quality for what it was. Things like that are only 'fatiguing' if you let the quality wind you up. Just relax, say to yourself 'it's AM' and let the mellow sound wash over you.

When we were young there wasn't broadband trashing all over MW. nor so many stations, and those were at pretty high power.


Or Optimod speach processors being pushed to their design limits.

DAB sounds worse than FM wrote:

The only station in the UK that uses 192 kbps. Yet Radio 3 still
sounds better on FM.

No it doesn't. Not that you ever listen to it.


Yeah, I've only been reviewing tuners for a hi-fi magazine for the last 3 - 4 years, and I obviously spend a lot of time comparing R3 on DAB and FM because the readership disproportinoately consists of R3 listeners, so WTF do I know about it?



This means **** all, any fool can write for a magazine and pass themselves
off as being an expert, look no further than the crap which is written about
Oxygen free cables and so called sound improvement devices which turn out
to be no more than £200 low pass filter.

In article , The Natural Philosopher
scribeth thus
tony sayer wrote:


Really, just how many comm stations do you think can be sustained?..

From a technological point of view, the available bandwidth divided by
the bit rate times the desired S/N ratio.


Mate they can't afford the DAB club;!..


From a commercial POV..no idea.

Lets say its bloody hard going for most all of them apart from those in
deprived areas who attract a lot more grant funding..

regards, Ian


--
Tony Sayer

In article , Ian
Smith scribeth thus
tony sayer wrote:



Funny that but my wife is a bit too young for listening to the Archers
but shes critical of the sound of FM and low rate DAB!...


I'm glad that she appreciates the benefit of higher rate DAB!

regards, Ian

Yes oddly enough she does .. but it comes via satellite from over in
mainland Europe..
--
Tony Sayer