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Technology Stocks : Sirius Satellite Radio (SIRI) -- Ignore unavailable to you. Want to Upgrade?

To: i-node who wrote (5295)	10/7/2006 12:32:35 AM
From: pcstel	Read Replies (1) \| Respond to of 8420

Does Sirius have some spectrum we don't know about? Are their current satellites not bent pipes, simply retransmitting whatever it is they receive? How will this new satellite "augment" capacity? Well, there have been a lot of advances in digital filtering and frequency reuse technology in the last few years, and it is has now become commonplace to share spectrum between the "space segment", and terrestrial. You can see this in the ATC systems for the MSS operators. Where the operator can use both the space segment and the terrestrial ATC systems on the same frequency via frequency re-use schemes. So the current state of SDARS is using a Frequency Division scheme where the Space Segment uses about half of their licensed spectrum, and the terrestrial segment uses ~ the other half. It is a very ineffecient system in today's spectral effeciencies. As the terrestrial segment simply mimics the broadcasts of what is transmitted on the space segment. In reality, there is no reason that you could not build a system that would allow frequency reuse of the terrestrial spectrum in the space segment, and like wise the space segment reuse in terrestrial segment. So basically, the entire ~12 Mhz could be employed in both the terrestrial and the space segment. So in effect.. You would double the available spectrum. (In the real world, it would be slightly less than an exact double) Now my viewpoint is that employing such a system. One would want a very robust terrestrial repeater network. As the rules stand. What ever is transmitted on the terrestrial network, must be transmitted on the space segment. And any "local content" must be transmitted also on the space segment. So, the most important aspect becomes "transmitting" on the space segment. Because if you can transmit it on the space segment. You can also transmit it on the terrestrial network that could provide a greater signal level than only the space segment. An example of this was the early days of C Band. Most of the C Band operators had a stipulation that in order to transmit their "SuperStation" type signals on C Band. They could only transmit to the satellite, when they were transmitting on their licensed TV channel (Superstation WTBS) in Atlanta. So whenever they had a transmitter problem that effected only their UHF Television Signal on Channel 17 in Atlnata. They had to pull their signal off of the satellite also. To make a long story short. We ended up installing a 5 watt UHF Solid State Exciter as a transmitter back up. So even if their main transmitter went down. They could still transmit to the satellite by transmitting a 5 watt signal from their local UHF back up antenna (Which was on top of the transmitter building about 20 foot off the ground). Now, no one could actually receive a signal from the local transmitter, but, they satisified the FCC requirements. Same thing could happen in SDARS, but with the terrestrial component being the more important component. For example. You could provide multiple commercial channels in the additional spectrum. A scheme were the subscriber could never receive the commercial channels directly on their radio (locked out). But, the radio would in effect switch between programs of music to the commercial insert channels which would be broadcasting a given commercial of local content into the subscriber accessable channels at a programmed time. But, since the local commercials are being transmitted over the space segment. They would be allowed under the current rules. Just my Guesses on what their plans may be. Best Regards, PCSTEL