New Portable Radio for Digital Satellite

"hwh" wrote in message
...

"Kristoff Bonne" schreef in bericht
...
Gegroet,


Max Demian schreef:
I bet you're one of these people that object to radio being delivered
via the internet being called radio, and TV delivered via broadband
being called TV?

Or a radio controlled clock a 'clock'.

Well, some of them are marketed as an "atomic clock". Is this correct?

It has atoms if it exists :-)

So those people exploded four atomic bombs in London a few weeks ago?

--
Max Demian

(reply to DAB, mainly ....)

You've tried to misrepresent what i said (in above post).

I was discussing antenna aperture, and said received SNR depends
strongly on that regardless of other factors (eg, Shannon's formula!).

The antenna is fairly low performance (ie, not a c band dish!), and
hence high field strength needed, as you say (with 1500 "fill in"
transmitters required, I believe, in addition to satellites).

So, due to high power needed, the data rate is low, just 1500(ish)
audio stations.

I don't understand "spectral efficiency" (there's exactly 1Mhz between
3Mhz and 4Mhz!). Did you mean "spectrum utilisation"? If not, then
what?

Yes, of course system performance will be consistent up to failure, due
to f.e.c., etc.

All transmission antenna are directional. ie, all have a polar
radiation pattern, sat or terr. Otherwise, I can't understand how
you're trying to define "directional" (it seems inconsistent). You have
to point a Ku band receiver dish antenna, which concentrates a low
power "beam", allowing many different satellites to be received, but
the XM receiver one must be omnidirectional, so has a much smaller
aperture.

Regarding my original point, describing Gnome as "sat radio receiver",
it would be the only uk "radio receiver" requiring a tv license!

spiney wrote:
(reply to DAB, mainly ....)

You've tried to misrepresent what i said (in above post).


No I've not.


I was discussing antenna aperture, and said received SNR depends
strongly on that regardless of other factors (eg, Shannon's formula!).


But the field strength of XM signals are FAR higher than the field
strength for Sky digital signals.


The antenna is fairly low performance (ie, not a c band dish!), and
hence high field strength needed, as you say (with 1500 "fill in"
transmitters required, I believe, in addition to satellites).


The repeater transmitters are only required for urban areas where
there's no line-of-sight reception. The field strength in line-of-sight
is adequate.


So, due to high power needed, the data rate is low, just 1500(ish)
audio stations.

I don't understand "spectral efficiency" (there's exactly 1Mhz between
3Mhz and 4Mhz!). Did you mean "spectrum utilisation"? If not, then
what?


spectral efficiency = data rate / bandwidth

e.g.

spectral efficiency = 2 Mbps / 1 MHz = 2 bits/s/Hz


Yes, of course system performance will be consistent up to failure,
due to f.e.c., etc.

All transmission antenna are directional. ie, all have a polar
radiation pattern, sat or terr.


Omni-directional antennas are omni-directional, so they're not
directional (for the horizontal plane).


Otherwise, I can't understand how
you're trying to define "directional" (it seems inconsistent).


Higher gain in one direction compared to another. Think of a Yagi's
radiation pattern.


You
have to point a Ku band receiver dish antenna, which concentrates a
low power "beam", allowing many different satellites to be received,
but the XM receiver one must be omnidirectional, so has a much smaller
aperture.


But the field strength is far higher to compensate for the lower antenna
gain. That is what I keep saying, and is what you keep ignoring.


Regarding my original point, describing Gnome as "sat radio receiver",
it would be the only uk "radio receiver" requiring a tv license!


Freeview receivers used for radio require a TV licence, amazingly.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

Find the cheapest Freeview, DAB & MP3 Player Prices:
http://www.digitalradiotech.co.uk/fr..._receivers.htm
http://www.digitalradiotech.co.uk/da...tal_radios.htm
http://www.digitalradiotech.co.uk/mp...rs_1GB-5GB.htm
http://www.digitalradiotech.co.uk/mp...e_capacity.htm

to DAB again ....

Once again, you're misreperesnting what i'm saying (deliberately, I
suspect!).

This being so, I'm still willing to reply to you, but only if:

1) You say exactly what the point is you're trying to make.

2) Define terms, if they're used in an unusual sense.

Just replying "yes it is..., no it isn't", without explanation, is
obviously a waste of time.

Thankyou.

Sorry, DAB, but Freeview receivers are always described as tv
receivers, never as radio receivers (quite deliberately, so that people
can't claim they don't need a tv license!).

"spiney" wrote in message
oups.com...
Sorry, DAB, but Freeview receivers are always described as tv
receivers, never as radio receivers (quite deliberately, so that
people
can't claim they don't need a tv license!).


Are you having a one sided conversation or are you posting your
replies to more groups than originally posted to, or is that crap
Google groups software broken again?!...

spiney wrote:
to DAB again ....

Once again, you're misreperesnting what i'm saying


No I am not, and I'm getting rather sick of this conversation.


(deliberately, I
suspect!).

This being so, I'm still willing to reply to you, but only if:

1) You say exactly what the point is you're trying to make.

2) Define terms, if they're used in an unusual sense.

Just replying "yes it is..., no it isn't", without explanation, is
obviously a waste of time.


What utter crap.

What it boils down to is that your assertion is incorrect that the
capacity is higher on DVB-S is due to the higher antenna gain of dishes
compared to the antenna gain for XM satellite digital radio receivers.

Basically, the transmission powers for XM are far higher than for DVB-S
to compensate for the lower antenna gain of XM receivers, and the
difference in SNR at the receiver input (after the antenna) will be very
similar for both systems - thus you bringing up Shannon's Capacity
Theorem is false.

Spectral-efficiency is another term for channel capacity, because
spectral efficiency is simply the channel capacity divided by the
bandwidth.

The spectral-efficiency of XM and DVB-S will be about the same, because
both use QPSK (2 bits/symbol) and both will be using similar FEC code
rates.

Basically, the reason why you can receive masses and masses of TV
channels and radio stations on DVB-S but you can only receive about 100
radio stations on XM radio is due to bandwidth, not the antenna at the
receiver. I've demonstrated that by proving that capacity is weakly
dependent on SNR, but you still won't accept what I'm saying.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

Find the cheapest Freeview, DAB & MP3 Player Prices:
http://www.digitalradiotech.co.uk/fr..._receivers.htm
http://www.digitalradiotech.co.uk/da...tal_radios.htm
http://www.digitalradiotech.co.uk/mp...rs_1GB-5GB.htm
http://www.digitalradiotech.co.uk/mp...e_capacity.htm

"DAB sounds worse than FM" schreef in bericht
...
Freeview receivers used for radio require a TV licence, amazingly.

Even if you have no device available to display the video information on?

gr, hwh

In article , DAB sounds
worse than FM writes


Freeview receivers used for radio require a TV licence, amazingly.

Amazingly wrong! If you have neither a device to display nor to record
the TV programmes (video information) then it is only a (digital) radio
receiver and no licence is required, see
http://www.tvlicensing.co.uk/information/index.jsp "Do I need a
licence?" - "If you use a TV or any other device to receive or record TV
programmes (for example, a VCR, set-top box, DVD recorder or PC with a
broadcast card) - you need a TV Licence. You are required by law to have
one", sound only programmes are not TV programmes.

--
Ian G8ILZ
Why must I state the obvious to the oblivious?

hwh wrote:
"DAB sounds worse than FM" schreef in bericht
...

Freeview receivers used for radio require a TV licence, amazingly.


Even if you have no device available to display the video information on?


But, if you live in the UK and don't have a television licence and do not even possess a TV, you
will be pestered annually as to why you don't have a licence. When I bought a Freeview box I
objected to having to fill in a form as to where I live etc. so the accommodating salesman put 'DVD
player' on the sale note :-)

--
Den [who does in fact have a TV licence!]