HOLLYWOOD, CALIF.—Shortly before the start of the SMPTE 2015 Annual Technical Conference & Exhibition, TV Technology spoke with John Maizels about the upcoming track of sessions “Is Coax Ready for the Undertaker?” for which he is the session chair.
TV TECHNOLOGY: Is 4K killing coax?
JOHN MAIZELS: You know, we've got so used to the ubiquity of coax that it's hard to imagine it going away. And it probably won't go away ever, but there are limits to what you can do with today's infrastructure. Some of that is related to coax, and some of it is related to the infrastructure that we interconnect with coax. It's no secret that 4K chews up four times as much bandwidth as 2K, and that's a challenge for architectures that are already stretched.
Some of the solutions are as simple as "use four times as much coax." Yep, that works, but it's a lot of resource tied up to achieve solutions that many would regard as suboptimal. So we're looking at ways to do more with the same, or something new that is smarter. That's what this session is about.
TVT: Steve Lampen of Belden told us last year that media facilities are moving toward Ethernet; most notably ESPN’s DC2. Is it simply easier to move to Ethernet than develop coax for higher bandwidth signals?
MAIZELS: You'd have to ask Steve about that, and I'm sure he's got a cool answer that involves a cable of some sort. The thing is that Ethernet isn't necessarily the answer to every question. You're actually talking about IP over Ethernet carried by unshielded twisted pairs, and an engineered solution means thinking beyond just cable and connectors. There's any number of ways of making an IP solution work, but SDI over coax has consistently exceeded the capabilities of IT networking of the day, and the next generation of high bandwidth video signals don't necessarily fit comfortably within the bandwidth boundaries of the IT networking technologies in common use. That leaves plenty of scope to consider solutions that extend the life of existing infrastructure by being clever with what we do.
TVT: What about connectors and interfaces? How do you phase out coax?
MAIZELS: Which begs the question: why do you want to phase out coax? We really need to understand that first before deciding that it has to go. In this session, we take two views about how you might stay with coax and push out even beyond 4K, and an alternative (and complementary) approach to using fibre very elegantly in a situation where coax has reigned supreme. There are a few SMPTE standards opportunities that come with these approaches, which makes the discussion more than timely.
TVT: What is the chief characteristic of coax that fiber, Ethernet, et al, do not provide?
MAIZELS: Accountants love anything that's depreciated, but still working; and engineers love anything they can fix with simple tools. That's coax! And then there's the practical characteristic: Who doesn't have a floor, walls, closets, racks and trucks full of coax? If your spaces are chock full of the stuff, then it makes sense to consider extending its life rather than doing an expensive rip and replace. That's not to say that new installations won't be fully IP and UTP -- many will in the years to come, but blue cable and fibre isn't the right answer for everyone and might not be for some time.
John Maizels combines life as a media versatilist and technologist in television and radio, with that of presenter, technical writer, sound editor, author and studio/OB operational crew. When not completely confused by this life, he teaches multicamera studio TV at college level and does voice overs. He is highly active in development of education and training for technologists, serves on the SMPTE Board as Governor for Asia/Australia Region, and is a Fellow of the SMPTE.
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