DenverTechie got right to heart of the deep fiber issues with the AT&T announcement for Salt Lake City. I can offer one additional factoid for consideration, though. Re: <Now, if ATA&T has figured out a way to power this network "just like the traditional phone network does" they would have to have retrofitted the entire network in Salt Lake and set up a large power distribution center at each headend. That has not happened to my knowledge. Also, fiber will not carry power, so there would have to be a cable conducting power along with the fiber to all locations. ... >
As I recall, SLC got a major rebuild for cascade reduction and to rearchitect to neighborhood node architecture back in the mid 1990s, at a time when the TCI design standard for such upgrade/rebuild work included placing what they termed a "communications cable" (I think that this procedure goes back into the late 1980s in TCI design standards.) The TCI "communications cable" was nothing but a continuous run of hard-line coax, paralleling the fiber. At the time, there was no clearly enunciated role for this coax, but now, it does seem to represent a possible ancillary conductor (an expensive one for the purpose!) for powering subscriber devices. Since it does not have line extender apparatus cases on it, with their current passing limitations, I suppose the National Electrical Code limits the voltage, and Ohm's law limits the current.
This is certainly not an answer for powering from the head end, so I absolutely concur with DT on that, but it might sidestep the need to retrofit the entire network for centralized (multiple power locations) powering. I do not suggest that using it for this purpose would be elegant, or even pretty. But it is a power-passing resource out there that as far as I know is fallow in all the systems where it was installed.
I wish I could tell you just what kind of coax it usually was; my vague recollection is that it was P-3.
p.s., to Wireless Wonk
You are of course absolutely correct about your distinction between C/I and C/N. In the systems work we did with modulation variations and testing, the question for us most conveniently included the MMDS system issues, so we usually discussed the integrated results in terms of C/I. As far as the signal propagation, we were skipping a step.
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