Mixed Signals
Any sufficiently advanced information is indistinguishable from noise
Friday 6 October 2006, 6:55 PM
Rupert Goodwins' Diary
Tuesday 3/10/2006
Home again, and my first chance to test out a piece of technology picked up Stateside. To bolster my collection of mildly weird radio hardware, I bought a pair of GMRS/FRS walkie-talkies for $50 at a Radio Shack — illegal to use but not to own in the UK, they highlight an ongoing problem with wireless standards.
GMRS and FRS are two CB-like bands unique to the US and Canada. They're just like any other two-way low power UHF radio system; in Europe — and increasingly the rest of the world, excluding America — we have something called PMR446. In all, however, there are around 10 such systems, each similar enough to each other to share hardware but dissimilar enough to require slightly different control software in the embedded processors that run the walkie-talkies.
As a result, the Far Eastern production lines that make these things churn out millions of identical units that can run on any standard, programming them to the restrictions of each market before shipping. But the darn things still all look the same and act the same: if you're not a radio regulator, you can't tell the difference, nor would you care.
But if you are — ah, you've got problems. These radios I've bought, for example, have 22 channels. The bottom bunch are in a government allocation in the UK for fire brigade and "inter-service liason", the middle lot are used by local radio stations for talkback from outside broadcasting, and the very top seem to be used by referees at football matches to talk to their linesmen. These are lightly scrambled to prevent the punters earwigging — but the walkie-talkies I have include exactly that form of scrambling.
Clearly, a mischief-maker with evil intent and one of these radios could have a lot of fun. There's no point in trying to ban their import; even if you succeed, it takes a few minutes on the Internet to find out how they're programmed and to switch bands on a unit that's been legally bought and certified for domestic use. (Incidentally, that's what I'm going to do with my pair, moving them into a nearby amateur radio band where I'm fully licensed to radiate at will.)
The solution — as with all radio, these days — is to settle on one band, one set of standards to do one job worldwide. It's worked with 802.11: it hasn't worked with 3G, and is only barely hanging together with WiMax. Regulators who don't take a truly global outlook will run the risk of losing control of their bands — it's happened in the past, when cheap CBs from the US overran the best efforts of the European regulators to keep them out, and that was before the Internet made buying a product from anywhere in the world somewhat easier than popping into Dixons. Do we see that kind of thinking with Ofcom and its pals around the world? Barely. There'll be trouble.
Incidentally, although it's normally illegal to listen to any of the frequencies my new radios cover, I have had a poke around, purely to make sure none of my other transmitters are interfering (a condition of my amateur radio licence, you understand). The inhabitants of the band appear to be Irish builders controlling cranes. It may be too late...
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