The British Broadcasting Corp. recently announced that it would discontinue its shortwave radio broadcasts to Europe, following the lead of other major shortwave services. The very mention of the phrase "shortwave" (the spectrum from about 3 to 20 MHz) brought a nostalgic image to my mind. Who hasn't seen those old movies
in which listeners are hunched by the radio, straining to hear news from abroad or perhaps a coded message ("elephants dance under the moon") while the signal fades, static and interference play havoc, deliberate jamming intrudes, and the radio drifts and needs retuning?
Shortwave radio is rapidly becoming a museum concept and historical artifact, right next to telegrams and postal letters. Among the reasons given by the BBC were a declining audience (an aging one, too, I suspect), the rise of online news and music, and the cost of running those multi-megawatt transmitters and their corresponding antenna farms.
The irony is that today's shortwave receiver is far cheaper, smaller and better than those of just a decade ago. But even those advances can't overcome limitations on reception and radio schedules.
But before we say goodbye to shortwave, it's worth taking a quick look at what it has taught us. It popularized low-noise front ends, antenna tuners to match impedances, dual- and triple-conversion superheterodyne architectures to optimize stage-by-stage performance and reduce images, and multiple filters to adapt to different signal modulations, among other functions. It also provided the platform for developing the PLL-based synthesized tuner with digital readout, which was far more accurate, precise, repeatable and stable than older "analog" tuners, along with advances in crystal oscillator design.
Even better, it taught us about electronics: Until the 1970s or so, you could build your own receiver from a kit (Heath, Knight and others) and end up with a fairly sophisticated product that you could troubleshoot and even modify.
We should keep one more thing in mind before we put shortwave in that shallow, barely marked grave our industry digs for its castoffs: We may be prematurely saying goodbye. The BBC pointed out that it will continue broadcasts to much of Africa and Asia, where Internet access is rare and costly, despite the intentions of One Laptop Per Child (OLPC) and similar programs.
Broadcast radio is still a very cost-effective way to reach remote, isolated and relatively poor regions with news, music and education. Sure, it lacks the flexibility, depth and broadness of the Web, but it is very real and very much here. We shouldn't let sophisticated solutions (OLPC and similar) get in the way of those that already work well for certain audiences and situations.