Well, it sure sounds like a 550 MHz system, but only Century knows the actual configuration.
The 77 channels would substantially exhaust a 550 MHz system for video. The cable radio could exist in channel 78 "in the roll off" region from 546 to 552 MHz and it uses a lot less than the 6 MHz of a video channel, like 2 kHz per channel, so no problem putting it up there. Channels 98 and 99 exist in the so-called "midband" region between channels 6 and 14. In fact, the spectrum between 90 and 120 MHz contains channels 95 through 99, so you actually have 3 spare video channels there.
A conventional carrier cable spectrum is kind of interesting to see how it is arranged for channels (that is opposed to a Harmonically Related Carrier system, known as an HRC system, but don't get me started).
The conventional system is set up like this, starting at 54 MHz, using 6 MHz per channel:
2,3,4,Guardband,5,6,95,96,97,98,99,14,15,16,17,18,19,20,21,22,7,8,9,10,11,12,13,23,24,25,26,27,28,29, and so on up to 93,94,100,101,102 and up.
So it sure looks like a pretty maxed out 550 system. Depending on how it was designed, you can build a 550 system that is spaced to handle 750 MHz equipment. Again, depending on what that spacing is, that could still take a drop in upgrade of amplifier modules to 860 MHz. If not, then a system upgrade would be needed. Also keep in mind that many 550 MHz systems were built without fiber in them and may be the case for you. Century MAY be trying to get away with no fiber if it is a relatively small cable network and low amplifier cascade count out of the headend.
It is, at least, theoretically possible and very dependent on several variables of system size, topology, original design, age of cable (old cable can pass 550 MHz usually without problem, but would have considerable heartburn at 860 MHz), and so on.
This is probably more than you wanted to know, but it sure explains a lot, doesn't it? That trick of putting the high channel numbers in the middle of the low spectrum can be quite misleading to those without a channel spectrum guide in sitting in front of them. |
