Manufacturers Highlight Mobile DTV at 2011 NAB Show

By Doug Lung
published


It was no surprise that transmitter manufacturers focused on Mobile DTV at this year's NAB. TV broadcast engineers now have a wide range of mobile exciters, multiplexers and encoding systems to choose from. Even better news is that while all manufacturers offer their own complete mobile DTV solution (exciter, multiplexer, encoder) and prefer you use their products, some of the exciters will work with a range of Mobile DTV multiplexers. Axcera was one of the companies claiming its exciter would work with streams from both the Rohde and Schwarz and Harris multiplexers. Larcan showed its first ATSC mobile DTV exciter/multiplexer/encoder solution while others, such as Harris, showed major upgrades to their first generation mobile DTV gear.

While not directly related to Mobile DTV, several new and updated digital on-channel repeaters (DOCRs) and single frequency network compatible exciters/transmitters were on display. Broadcasters are likely to need to use one of these technologies to improve reception on mobile/handheld devices inside buildings or in areas obstructed by terrain. Some of the new DOCRs, like those from Linear and Screen Services, claim the ability to work even if the output signal at the input to the repeater is 30 dB or more above the received signal to be repeated. This should simplify installation and allow greater output powers. Lower power transmitters in a single frequency network and digital on-channel repeaters need mask filters to protect adjacent channels. I was pleased to see Dielectric (SPX), RFS and others offering low power, compact filters that were able to meet the full power emission mask.

I did not see as many new products in the antenna/transmission line category as in previous years. One new product that stood out was ERI's 1329Line rigid transmission line, which combines the copper inner conductor from ERI's MACXLine with an aluminum outer conductor. ERI said power handling and loss for the hybrid line is comparable to that of all copper line, at a much lower cost and lighter weight.

I'll have more details on these and other products in my June RF Technology column in TV Technology magazine.

Doug Lung
Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. As vice president of Broadcast Technology for NBCUniversal Local, H. Douglas Lung leads NBC and Telemundo-owned stations’ RF and transmission affairs, including microwave, radars, satellite uplinks, and FCC technical filings. Beginning his career in 1976 at KSCI in Los Angeles, Lung has nearly 50 years of experience in broadcast television engineering. Beginning in 1985, he led the engineering department for what was to become the Telemundo network and station group, assisting in the design, construction and installation of the company’s broadcast and cable facilities. Other projects include work on the launch of Hawaii’s first UHF TV station, the rollout and testing of the ATSC mobile-handheld standard, and software development related to the incentive auction TV spectrum repack. A longtime columnist for TV Technology, Doug is also a regular contributor to IEEE Broadcast Technology. He is the recipient of the 2023 NAB Television Engineering Award. He also received a Tech Leadership Award from TV Tech publisher Future plc in 2021 and is a member of the IEEE Broadcast Technology Society and the Society of Broadcast Engineers.