Powering the CATV network. Traditional ferroresonant is compared to modern switch-mode UPS technology

As cable TV networks increasingly support far more than TV programming, the need for high quality, high reliability power will become more evident. Traditional and modern methodologies are presented and studied in the context of the outdoor cable plant environment. The power distribution system, from the utility input-the standby supply-the coaxial cable network-through to the distributed, constant power loads, are considered together to evaluate suitability of the UPS technology used in the standby supplies. Severe line voltage surges and wide temperature extremes are obvious challenges. Voltage drops in long cable runs are understood to be aggravated by the constant power demand of the "powerpak" loads spread throughout the network. The more subtle voltage drop due to unexpected sheath currents in the coax cable is shown to be potentially more disruptive of network power and damaging of network equipment. Modern switch-mode UPS technology is examined and compared to the ferroresonant standby supply in the context of these operational challenges.