Fun with Infrastructure

Last month The Kid and I went to the top of the Empire State Building on the kind of day pilots describe as “severe clear.” I put some of the shots up here, and just added a bunch more here, to share with fellow broadcast engineering and infrastructure obsessives, some of whom might like to help identify some of the stuff I shot.

Most of these shots were made looking upward from the 86th floor deck, or outward from the 102nd floor. Most visitors only go to the 86th floor, where you can walk outside, and where the view is good enough. It costs an extra $15 per person to go up to the 102nd floor, which is small, but much less crowded. From there you can see but one item of broadcast interest, and it’s so close you could touch it if the windows opened. This is the old Alford master FM antenna system: 32 fat T-shaped things, sixteen above the windows and sixteen below, all angled at 45°.

From the 1960s to the 1980s (and maybe later, I’m not sure yet), these objects radiated the signals of nearly every FM station in New York. They’re still active, as backup antennas for quite a few stations. The new master antennas (there are three of them) occupy space in the tower above, which was vacated by VHF-TV antennas (channels 2-13) when TV stations gradually moved to the World Trade Center after it was completed in 1975.

When the twin towers went down on 9/11/2001, only Channel 2 (WCBS-TV) still had an auxiliary antenna on the Empire State Building. The top antenna on the ESB’s mast appears to be a Channel 2 antenna, still. In any case, it is no longer in use, or usable, since the FCC evicted VHF TV stations from their old frequencies as part of last year’s transition to digital transmission. Most of those stations now radiate on UHF channels. (All the stations continue to use their old channel numbers, even though few of them actually operate on those channels.) Two of those stations — WABC-TV and WPIX-TV — have construction permits to move back to their old channels (7 and 11, respectively).

That transition has resulted in a lot of new stuff coming onto the Empire State Building, a lot of old stuff going away, and a lot of relics still up there, waiting to come down or just left there because it’s too much trouble to bother right now. Or so I assume.

For some perspective, here is an archival photo of WQXR’s original transmitting antenna, atop the Chanin Building, with the Empire State Building in the background. The old antenna, not used in many years, is still up there. Meanwhile the Empire State building’s crown has morphed from a clean knob to a spire bristling with antennae.

Calling the Fat Tail

I think I’ve figured out a lot of what’s up there, and have made notes on some of the photos. But I might be wrong about some, or many. In any case, a lot of mysteries remain. That’s why I’m appealing to what I call the “fat tail” for help.

The “fat tail” is the part of the long tail that likes to write and edit Wikipedia entries. These are dedicated obsessives of the sort who, for example, compile lists of the tallest structures in the world, plus the many other lists and sub-lists linked to from that last item.

Tower freaks, I’m talking about. I’m one of them, but just a small potato compared to the great , who reports on a different tower site every week. Among the many sites he has visited, the Empire State Building has been featured twice:  January 2001 and November 2003. Maybe this volunteer effort will help Scott and his readers keep up with progress at the ESB.

This Flickr set, by the way, is not at my home pile, but rather at a new one created for a group of folks studying infrastructure at Harvard’s Berkman Center, where I’m a fellow. I should add that I am also studying the same topic (specifically the overlap between Internet and infrastructure) as a fellow with the Center for Information Technology and Society at UCSB.

Infrastructure is more of a subject than a field. I unpack that distinction a bit here. My old pal and fellow student of the topic, , visits the topic here.

Getting back to the Empire State Building, what’s most interesting to me about the infrastructure of broadcasting, at least here in the U.S., is that it is being gradually absorbed into the mobile data system, which is still captive to the mobile phone system, but won’t be forever. For New York’s FM stations, the old-fashioned way to get range is to put antennas in the highest possible places, and radiate signals sucking thousands of watts off the grid. The new-fashioned way is to put a stream on the Net. Right now I can’t get any of these stations in Boston on an FM radio. In fact, it’s a struggle even to get them anywhere beyond the visible horizons of the pictures I took on the empire State Building. But they come in just fine on my phone and my computer.

What “wins” in the long run? And what will we do with all these antennas atop the Empire State Building when it’s over? Turn the top into what King Kong climbed? Or what it was designed to be in the first place?

Infrastructure is plastic. It changes. It’s solid, yet replaceable. It needs to learn, to adapt. (Those are just a few of the lessons we’re picking up.)

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  1. Andrew Back’s avatar

    I’m always amazed, and saddened, that so few radio users share infrastructure. Mast sharing is more common, and here in the UK we have companies such as NTL that own a lot of sites and rent out space and provide managed services etc. But you would think that a lot more of this would go on.

    I have often wondered if software-defined radio might open up new possibilities for radio service provision, where this is in effect virtualised. Service providers would have consolidated platforms with wideband RF front ends and antenna farms. High speed DACs/ADCs would sit between these and the software layer. Provisioning would involve pushing out software modules to support the required DSP graphs (e.g. ‘apt-get install 16qam’), and backhaul would be over IP. No more massive energy losses in the combiner of a multi-channel TX chain – complex carriers (e.g. multiple GSM channels) would be combined in software and amplified as a wideband signal. Fire, police, ambulance and commercial radio etc. all off one system. New services would be possible, as temporary national transmissions could easily be set up and brought down at a greatly reduced cost.

  2. Doc Searls’s avatar

    Andrew, your mouth to geeks’ ears. (An explanation, for those who don’t get the line.)

    The UK, and Europe in general, has been far more sane about radio and television infrastructure than we have here in the States. I know of many places where competing TV stations built 2000-foot towers, side-by-side, rather than one common one that all could use — to the hazard of aviation, bird migration, and common sense. You guys also invented and deployed RDS sensibly, while we used it only to give stations a way to display call letters or whatever. (For those who don’t know, RDS is a lightweight digital add-on to analog broadcasts that allows a radio to stick with a single station as the user moves from one transmitter’s coverage area to another. It will also set your clock, interrupt your CD listening for traffic notices and display up to eight upper-case characters of static or moving text. It was created in the early ’90s, deployed everywhere in Europe, and largely ignored in the U.S., which adopted a deprecated variant called RDBS, but never called that.)

    Anyway, you have my head spinning. Well done!

  3. Andrew Back’s avatar

    Doc, I’m glad to hear that someone else finds the idea of SDR enabled radio systems consolidation interesting. I can’t help but marvel at the possibilities… Especially when you also factor in smart antennas and, via SDR, cognitive radio systems that could bring about new levels of spectrum use efficiency. Imagine what would be possible if you had a common platform which “knew” about all the various users, could maintain dynamic channel schemes, worry about interference modes, track the position of mobile stations and employ beamforming.

    I didn’t realise that we were ahead in our use of RDS, and was shocked when I heard some 10 years ago or so that we were ahead of the US with GSM. OK, so GSM is from ETSI (the ‘E’ for European), but the US alternatives seemed to seriously lag in terms of capabilities.

    Getting back to radio system futures: have you heard of Digital Radio Mondiale? This is one future I don’t want to see. Call me old fashioned, but I’d like to see the conservation of HF, almost like a nature reserve. For it to be kept a place where simple, handmade equipment can play. Where the romanticism of sporadic overseas radio via skywave can be experienced. Narrowband amateur digital modes are fine, but the idea that there will be a proliferation of high power, digital commercial radio stations strikes me as abhorrent.

  4. Doc Searls’s avatar

    I like the idea of a common platform, as long as one company doesn’t own it. (As, say, Ibiquity owns “HD Radio” here in the U.S.) As for GSM, there are many that would argue that Qualcomm’s CDMA is superior, but that’s beside the point. We have two competing and incompatible systems now.

    I didn’t know much about Digital Radio Mondaile. (That link goes to the Wikipedia entry, which seems solid.) It strikes me as a futuristic approach to a retro problem. Need to think more about it, though. Meanwhile, I’m in sympathy.

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