Sounds of the Earth

During my downtime the past few nights, I’ve been listening to and reading up on a pair of phenomena that involve strange radio transmissions.

Have you ever heard of Numbers Stations? These are radio stations on the shortwave band whose only job is to transmit a random-sounding series of numbers either by voice, Morse code, or noises. It is theorized that they are used by governments to send coded messages to their operatives out in the field, yet no single government will admit to using them. A Ham listener can use signal triangulation to locate the transmitting antenna, but there’s no clear way of knowing who the station serves and what its message is.

The use of Numbers Stations is actually growing even after the fall of the Berlin Wall and the end of the Cold War (some would argue that the Cold War never actually ended). Even in this day and age of high-speed communications and strong encryption, the fact that clandestine activities still happen with this antiquated technology bears testament to the fact that this is probably the only truely anonymous form of communication.

Since the last few decades of last century, there’s been growing public awareness and concern regarding Numbers Stations, and various researchers, Ham operators, and writers have taken to the cause of documenting these stations, logging their existence, writing down the patterns of numbers, and making audio recordings for a wider distribution outside the amateur radio realm. One such collection was compiled by the Irdial netlabel of England on a 4-CD set called the “The Conet Project – Recordings of Shortwave Numbers Stations“. Irdial has been kind enough to release this collection for public download at I suggest you read the Wikipedia article, grab the collection, and take a listen. It’s chilling, haunting, and a thrill to hear.

The next phenomenon, though not as clandestine, is still sharply related to the first. Mankind has been hearing strange noises ever since the first 20-mile telegraph line. Operators would hear clicks, pops, whistles and chirps coming out of their receiver sets in between all of the buzzer noises of the telegraph transmission. What they didn’t know at the time, and what we’ve discovered over the last century since the telegraph, is that they were hearing electromagnetic noises generated by the Earth. Every lightning strike, every Aurora Borealis, every solar particle, cosmic ray, burst of energy that strikes the Earth, emits a broad range of electromagnetic noise across the whole frequency spectrum, from DC current up to visible light.

But the electromagnetic frequencies clustered within our human range of hearing (called VLF, or Very Low Frequency) are the most interesting. With the right radio receiver — essentially a large antenna to pick up the noise, an amplifier, an audio filter, and an amp to power a speaker or headphones  — you can listen to these pops and whistles yourself. Researchers have been building these radios and studying the noises for decades, making years-worth of audio recordings. Irdial published a collection of recordings called “Electric Enigma: The VLF Recordings of Stephen P. McGreevy” (also found on, gathered by McGreevy on his outings around the Northern hemisphere using equipment he built himself. I suggest you grab it too; the sounds are incredible.

These restore my faith that, even at my age, there still might be some wonder left in this world.

Three. One. Seven. Five. Nine.

Published by Shawn

He's just this guy, you know?