Wednesday, July 16, 2008

Mobile TV for the Bottom Billion

It’s a ringing endorsement of the subversive power of a technology when the Chinese government tries to block it. A technology that I only vaguely remember by the tantalizing “Radio Luxembourg” label on the dial of my family’s old valve-powered Telefunken is still going strong: 105 million of the BBC World Service’s 182m-strong global audience still listen to the Bush House via short-wave radio (Snap and crackle goes pop, The Economist, 19 Jun 2008).

Long-range radio is getting a digital make-over in the form of the Digital Radio Mondiale (DRM), a format designed for frequencies below 30 MHz (Stay tuned,, 8 Jan 2008). DRM provides the same range as these traditional AM transmissions without the interference. (There is an alphabet soup of digital audio broadcasting standards; see wikipedia.)

But the basic premise of the digital transition is wrong: it just takes a service – TV, say, or radio – in a given band and digitizes it. Digital is “better”, though instead of one higher-quality broadcast replacing the analog one, the shift in practice is to “more”. None of the digital standards are different enough to make a real difference. Still TV, just more channels. Still radio, just more channels. This is lergely due to inflexible spectrum allocation; radio licensees can only broadcast radio.

There should be shift in kind, not in quantity. Replace radio by TV; replace TV by two-way data networks.

Cheap computing and clever algorithms means that one can just about squeeze an sub-analog-quality TV signal into a short-wave radio band.* That means that in a few Moore’s Law cycles, you’ll be able to get not-too-bad TV on the equivalent of a transistor radio.**

To be clear: this idea is not intended for the non-poor, and definitely not for the rich who are moving from radio to the internet for their audio in increasing numbers. But if you gave the people in the Bottom Billion a choice – say, those 105 million people who still listen to the Beeb on a shortwave radio – would would they pick crystal-clear digital radio, or junky hand-held TV that fits in their pocket and runs off a hand-crank? Which would the Chinese government be more afraid of? I'm with the Buggles: Video will kill the radio star.

(By the rule that if I can think of something, someone's already done it, some enterprising grad student has probably already lashed together a TV transistor radio - but a cursory web search didn't turn it up. Please shout if you know who's been there and done this.)


* According to the Flash Video bitrate calculator, a talking head at 320x240 resolution with decent mono audio needs 100 kbps (120 kbps recommended). That’s way to much for a Digital Radio Mondiale stream, which delivers 17-35 kbps in a 10 kHz channel (wikipedia, But if you’re willing to live with 160x120 and low quality mono sound, that’s 29 kbps FLV bitrate (35 kbps recommended). Another turn of the codec crank, and we’ll fit.

** Perhaps the biggest cost – and these No-Def TVs will have to be veeeery cheap – will be the LCD screens, which don’t obey Moore’s Law. But the volume of screens being made for iPhones and their ilk wil surely drive down that cost.