…6 9 1 Echo Alpha. 6 9 1 Echo Alpha. 6 9 1 Echo Alpha…

There’s an invisible worlds out there beyond the medium-wave. Tune into the shortwave and you can hear everything—ham operators from Zimbabwe, horse race results, intra-agency channels from the BBC, airplanes flying in the Arctic, trawling boats from Scotland, American time signal regulators. But what interests me most of all are those stations that relay series of numbers.

Attention. Attention. Attention. 3 Lima 4 1 5. 3 Lima 4 1 5…

Nobody ever owns up to them. We’ve found out who operates a few of them, but we’re not sure what they are. They’re probably spy stations. There was one definitively ID’d as a spy station once.

…3 Lima 4 1 5. [series of polytones]

I switch the dial, scanning the airwaves to see if there’s any other traffic. I hit a hot spot, go on past…but it sounds familiar, like an old friend unseen for awhile. I go back.

I know those fifteen notes.

I smile. After a two-year hiatus, the Lincolnshire Poacher is back on the air.