Re: [Swprograms] Satellite Radio Questions

[Richard Cuff <rdcuff@xxxxxxxxx>]

No, it isn't infinite capacity.  Sirius recently developed new data
compression algorithms that allow them to squeeze more audio onto the
same bandwidth.

Right now, those exclusively for Canadians take advantage of a new
Sirius chipset that existing USA receivers don't have.  This new
chipset will be utilized starting in early 06.  I don't know if we
will need new receivers in the USA to get the channels numbered above
184.

For Sirius, channel numbers were not duplicated.  Canadian
subscribers' receivers have the "invalid" channels filtered out. 
Their radios are in fact receiving these channels, but the software /
firmware inside the receiver blocks the user from being able to select
the invalid channels.  Somewhat like scrambling cable channels in
concept.

This means that CBC Radio One is channel #137 both in the USA and
Canada.  Howard Stern will be channel #100.  Canadian radios simply
won't be able to tune to that channel.

Your analogy on channel assignment and identification is correct -- it
simply points to a portion of the datastream coming from the
satellite.  Both Sirius and XM were assigned the same frequency range
for their satellites -- 2320 to 2332.5 mHz.

I suspect the approach of Sirius -- not reusing channel IDs -- will
persist as long as the service exists.  There was already one
expansion on September 30th which incorporated, annoyingly,
substantial renumbering which required presets to be programmed in
many instances.

The concept of "limitless" bandwidth only applies to the extent that
Sirius and XM can develop enhanced codecs (compression / decompression
algorithms) to more efficienty sample and squeeze the signal in what
is inherently a "lossy" compresion technique.  XM and Sirius use
different codecs and (presumably) different encryption algorithms.

Hope this clears things up...

Richard Cuff / Allentown, PA  USA

On 12/1/05, William Martin <wgmartin@xxxxxxxxxxx> wrote:
> Some questions came to mind while I was reading the recent
> items in DXLD & etc. about the expansion of Sirius into Canada:
>
> They're listing new channels being added, some for everyone
> but with Canadian content, and some exclusively for the
> new Canadian subscribers. Do these satellite-radio providers
> have lots of spare bandwidth available to just add more channels
> anytime they wish? Is it essentially infinite capacity?
>
> Just how does this work? If you're a subscriber in Category A,
> and you punch in channel number 199, you get program X. If
> you're a subscriber in Category B and punch in 199, do you get
> program Y -- something different on the same channel number?
> So "A" could represent regular US subscribers, and "B" indicate
> the new Canadian group of customers?
>
> Is the channel number not a frequency selection at all, but just
> a data entry pointing to a different data stream in the flood of
> digital data coming from the satellite? And thus the "channel"
> designations all depend on what you as a subscriber are
> entitled to hear, depending on what you've paid for?
>
> So could the channel numbers increase forever or do they
> try to keep them all in the same number range by re-using
> the designations for each tier or class of subscription?
>
> Does XM work the same way as Sirius, just with different
> encryption?
>
> 73, Will
>
>
> _______________________________________________
> Swprograms mailing list
> Swprograms@xxxxxxxxxxxxxxxx
> http://arizona.hard-core-dx.com/mailman/listinfo/swprograms
>
> To unsubscribe:  Send an E-mail to  swprograms-request@xxxxxxxxxxxxxxxx?subject=unsubscribe, or visit the URL shown above.
>
>

_______________________________________________
Swprograms mailing list
Swprograms@xxxxxxxxxxxxxxxx
http://arizona.hard-core-dx.com/mailman/listinfo/swprograms

To unsubscribe:  Send an E-mail to  swprograms-request@xxxxxxxxxxxxxxxx?subject=unsubscribe, or visit the URL shown above.