On 1/12/12 8:10 AM, Jeff Liebermann wrote:
Incidentally, there's another nightmare pending, that oddly involves
yet another potential source of GPS interference. In EU, the official
future all digital broadcast band is 1452 to 1492 MHz. There's no
hardware, and several countries are just sitting on the spectrum, but
that's the official ITU dictated direction for S-DAB.

No, the official EU digital (radio +) band is 174-240 MHz. The 'L-band'
you mentioned has been used for digital radio, but it is not suitable
for terrestrial distribution because the frequencies are too high. There
now remain a few transmissions from satellite and just a few thousand
receivers scattered around the continent. I wonder what will happen to
the frequency allocation in 2012.

gr, hwh

On Thu, 12 Jan 2012 09:52:47 +0100, hwh
wrote:

On 1/12/12 8:10 AM, Jeff Liebermann wrote:
Incidentally, there's another nightmare pending, that oddly involves
yet another potential source of GPS interference. In EU, the official
future all digital broadcast band is 1452 to 1492 MHz. There's no
hardware, and several countries are just sitting on the spectrum, but
that's the official ITU dictated direction for S-DAB.

No, the official EU digital (radio +) band is 174-240 MHz. The 'L-band'
you mentioned has been used for digital radio, but it is not suitable
for terrestrial distribution because the frequencies are too high. There
now remain a few transmissions from satellite and just a few thousand
receivers scattered around the continent. I wonder what will happen to
the frequency allocation in 2012.

gr, hwh

I can't predict what will happen in Europe, but in the US, I think
1.5Ghz would be a likely place to move digital radio. How it will be
organized and structured is beyond the abilities of my crystal ball.

As for being unsuitable for terrestrial, please note that Sirius is
using 2320 to 2332.5MHz and XM at 2332.5 to 2345MHz. While allegedly
a satellite based DAB system, much of the urban coverage is via
terrestrial repeaters, primarily to deal with "urban jungle" building
blockage. If 2.3Ghz works, certainly 1.5Ghz will also work.

Sirius repeater map:
http://www.dogstarradio.com/sirius_map.php

"Indoor" repeater:
http://www.uniquesys.com/DVB/DVB_Transmitters/50WRPTR-Indoor-Repeater.php

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 1/12/2012 8:40 AM, Jeff Liebermann wrote:

As for being unsuitable for terrestrial, please note that Sirius is
using 2320 to 2332.5MHz and XM at 2332.5 to 2345MHz. While allegedly
a satellite based DAB system, much of the urban coverage is via
terrestrial repeaters, primarily to deal with "urban jungle" building
blockage. If 2.3Ghz works, certainly 1.5Ghz will also work.

I've only had a rental car with satellite radio once, but I was amazed
at how poor satellite radio performed. There apparently is little
buffering, so if I were under an overpass for more than a few seconds
the signal would be lost. The audio quality was mediocre. Maybe
satellite radio is good for Howard Stern, but not for music. I thought
that maybe the GM car I had simply had a sound system that didn't do
satellite radio justice. I see a lot of complaints about satellite radio
signal loss and audio quality, i.e. "their quality isn't even FM Quality."

What is the bit rate for XM/Sirius music channels? I've seen people say
that it's as low as 32 kb/s, but that their streaming is 128 kb/s. But
if you're streaming, you may as well get Pandora rather than satellite.

"I just thought I would give you guys the heads up for those who are
interested. The increased audio quality of XM in my car (via streaming
through my phone) has allowed me to re-discover and enjoy the music XM
offers. If only they could bump up the quality though their actual
satellite service..."

So now this person is paying for unlimited data on their phone PLUS an
XM subscription.

On 1/12/12 6:49 PM, SMS wrote:
I've only had a rental car with satellite radio once, but I was amazed
at how poor satellite radio performed. There apparently is little
buffering, so if I were under an overpass for more than a few seconds
the signal would be lost. The audio quality was mediocre. Maybe
satellite radio is good for Howard Stern, but not for music. I thought
that maybe the GM car I had simply had a sound system that didn't do
satellite radio justice. I see a lot of complaints about satellite radio
signal loss and audio quality, i.e. "their quality isn't even FM Quality."

What is the bit rate for XM/Sirius music channels? I've seen people say
that it's as low as 32 kb/s, but that their streaming is 128 kb/s. But
if you're streaming, you may as well get Pandora rather than satellite.

Funny that you say that, because they use an average of about 46 kbps,
which is actually over the average used for HD radio. That this is not
adequate to match FM is what we are trying to tell you for some time now.

gr, hwh

On 1/12/2012 9:53 AM, hwh wrote:

Funny that you say that, because they use an average of about 46 kbps,
which is actually over the average used for HD radio. That this is not
adequate to match FM is what we are trying to tell you for some time now.

Where did you get the idea that HD averages less than 46 kbps? If it's
HD1 only then it's 96 kbps. If there are sub-channels they divide that
up, but unless they have more than one sub-channel, the average could
not be less than 48 kbps.

Also remember that once analog is turned off there will be 300 kb/s to
be divided up among the channels.

In any case, there's no contest between the quality of audio on
satellite radio and HD Radio, HD Radio is far better. The difference is
in coverage. HD Radio coverage is very limited on stations that have not
taken advantage of the power increase.

On 1/12/12 7:20 PM, SMS wrote:
On 1/12/2012 9:53 AM, hwh wrote:

Funny that you say that, because they use an average of about 46 kbps,
which is actually over the average used for HD radio. That this is not
adequate to match FM is what we are trying to tell you for some time now.

Where did you get the idea that HD averages less than 46 kbps? If it's
HD1 only then it's 96 kbps. If there are sub-channels they divide that
up, but unless they have more than one sub-channel, the average could
not be less than 48 kbps.

Most stations use subchannels. There are very few stations using more
than 48 kbps. The difference between 46 and 48 kbps or something like
that will be hard to notice.
Of course the smart thing to do would be to use the digital for a second
service *only* and leave the first one on FM (for now). For instance an
owner of an AM and an FM station might simulcast the AM on the HD at 96
kbps to lure the audience over. The big saving would come when the AM
can be switched off. The FM would of course benefit when the FM goes as
well and the bandwidth goes up. A third station could be added then.


Also remember that once analog is turned off there will be 300 kb/s to
be divided up among the channels.

Of course, but that is of no use at all for now and many years to come.

In any case, there's no contest between the quality of audio on
satellite radio and HD Radio, HD Radio is far better.

Bitrates are similar, sound is similar. I tried both. There are a few
positive exceptions though, indeed some of the ones transmitting just
one service.

gr, hwh

On Thu, 12 Jan 2012 09:49:15 -0800, SMS
wrote:

What is the bit rate for XM/Sirius music channels? I've seen people say
that it's as low as 32 kb/s, but that their streaming is 128 kb/s. But
if you're streaming, you may as well get Pandora rather than satellite.

It's ugly. There are 100 streams, each 8Kbits/sec. With two
channels, they're effectively 4Kbits/sec per channel. These are
conglomerated in the receiver into anything between 4 and 64Kbits/sec.
For music, it seems to hang around the upper end, but I'm not sure.
http://www.google.com/patents/US7075946?dq=7075946
I had XM in my car several years ago when they were giving away 30
days free trials. Coverage in the San Lorenzo Valley was horrible due
to trees, hills, and lack of terrestrial repeaters. The nearest are
two in San Jose.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 1/12/2012 11:40 AM, Jeff Liebermann wrote:
On Thu, 12 Jan 2012 09:49:15 -0800,
wrote:

What is the bit rate for XM/Sirius music channels? I've seen people say
that it's as low as 32 kb/s, but that their streaming is 128 kb/s. But
if you're streaming, you may as well get Pandora rather than satellite.

It's ugly. There are 100 streams, each 8Kbits/sec.

I found a chart here http://www.xm411.com/phpbb/viewtopic.php?t=33127.
It's nearly four years old, but since the satellite radio providers
obviously don't want to talk about bit rates, it'll have to do. It's
pretty clear where the complaints of audio quality on satellite are
coming from. Much lower than even free Pandora in most cases. I can only
imagine the kind of stuff we'd see posted here if digital terrestrial
radio tried to get away with some of those bit rates for music. I can
just imagine some of the radio conglomerates thinking about three 32
kbps digital music channels (or seven once analog is turned off).

What's amazing is that after coming close to failing, satellite radio in
the U.S. is now doing okay financially (not great, but the threat of
bankruptcy is over) so obviously there are many consumers for whom audio
quality is of minimal importance. They even raised prices recently. I
could buy a couple of hundred music CDs at garage sales for what it cost
for satellite radio for a year.

On long trips we like to listen to audio books, and most libraries have
a very good selection.

On Thu, 12 Jan 2012 12:09:37 -0800, SMS
wrote:

It's nearly four years old, but since the satellite radio providers
obviously don't want to talk about bit rates, it'll have to do.

Actually, I'm not all that interested in bit rate. What methinks is a
problem is the error rate. You could be running the full 64Kbits/sec
per channel, but with a sufficiently high uncorrectable error rate,
the quality will suck. FEC helps, but isn't a cure all. Same problem
with HD Radio. It's difficult enough to find the data rate without
ripping open the receiver and probing the guts. Getting the error
rate is even more difficult.

It's
pretty clear where the complaints of audio quality on satellite are
coming from.

Ummm... the complaints are coming from listeners. Should they be
coming from elsewhere?

... obviously there are many consumers for whom audio
quality is of minimal importance.

I guess that includes me. You wouldn't believer the OTA FM noise I
have to tolerate. Driving through the hills, the stations alternately
appear and disappear. In between the radio just belches noise. Trying
to hear anything over the road noise, scanner, and 2way radio noise is
difficult. Meanwhile, the GPS mapping display is yelling at me to
turn here and there. At the same time, my Droid is mumbling something
about email and reminders. Even if the music were distortion free, I
probably wouldn't notice.

On long trips we like to listen to audio books, and most libraries have
a very good selection.

Well, they've passed laws against driving while talking on the phone.
Perhaps the next step is to pass a law against driving while listening
to audio books. It's too much of a distraction for the GUM (great
unwashed masses).

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On 1/12/12 5:40 PM, Jeff Liebermann wrote:
On Thu, 12 Jan 2012 09:52:47 +0100, hwh
wrote:

On 1/12/12 8:10 AM, Jeff Liebermann wrote:
Incidentally, there's another nightmare pending, that oddly involves
yet another potential source of GPS interference. In EU, the official
future all digital broadcast band is 1452 to 1492 MHz. There's no
hardware, and several countries are just sitting on the spectrum, but
that's the official ITU dictated direction for S-DAB.

No, the official EU digital (radio +) band is 174-240 MHz. The 'L-band'
you mentioned has been used for digital radio, but it is not suitable
for terrestrial distribution because the frequencies are too high. There
now remain a few transmissions from satellite and just a few thousand
receivers scattered around the continent. I wonder what will happen to
the frequency allocation in 2012.

gr, hwh

I can't predict what will happen in Europe, but in the US, I think
1.5Ghz would be a likely place to move digital radio. How it will be
organized and structured is beyond the abilities of my crystal ball.

As for being unsuitable for terrestrial, please note that Sirius is
using 2320 to 2332.5MHz and XM at 2332.5 to 2345MHz. While allegedly
a satellite based DAB system, much of the urban coverage is via
terrestrial repeaters, primarily to deal with "urban jungle" building
blockage. If 2.3Ghz works, certainly 1.5Ghz will also work.

Sirius uses a dual distribution system, with satellite and terrestrial.
In Europe they tried to use L-Band for terrestrial-only and that doesn't
work. You simply needed too many repeaters, making the system too expensive.

Satellite broadcasting does not work in Europe because there are many
markets. They are too small to make them viable targets. Band III
systems need less transmitters and can easily be split into many
markets. The end of analog TV freed up significant portions of the band
for digital radio (and other services sharing the multiplexes). Digital
TV is moving to UHF-only in many countries, even in less airspace than
before because governments want to cash in on frequencies for mobile
internet. No significant use has been decided (yet) for Band I frequencies.

gr, hwh