Recently I received a radio built by Stephen McGreevy, N6NKS. The WR-3 is a hand-held VLF receiver designed for especially for listening to naturally-occurring extremely low frequency (ELF) and very low frequency (VLF) radio phenomena, like lightning storm atmospherics. The WR-3 converts 0.2-11 kHz radio frequencies directly to audio signals, which can be monitored and recorded directly from a portable hand-held unit powered with a 9-volt battery. Using this and similar models, Stephen produced five natural VLF radio MP3 Albums, including, "Electric Enigma" and "Aurora Chorus". For an example listen here.
As Steve notes, "Everyone has seen or has at least heard of the hauntingly beautiful Aurora Borealis or Northern Lights but only a select and elite few have experienced their spectacular, compelling and beautiful sound". Steve has for the first time in history, captured and recorded "the sounds of the Aurora Borealis and the EMF discharges of lightning bolts bouncing and stretching through the earth's magnetosphere."
Yesterday afternoon I drove out to a place called Little Mountain on the Natchez Trace Parkway at Jeff Busby Campground in Mississippi, turned off my car, plugged in some iPhone earbuds and then the W3R. Initially the earbuds literally buzzed in my hand after I turned on the receiver; I'm glad I did not have them in my ears, but I had read about this and knew to be careful.
After adequately grounding the radio (or was it just hand capacitance?) the earbuds stopped chattering in my hand and I carefully put them in my ears. First I heard a slight bit of power-line hum and lots of noisy interference, which I attributed to some large machinery a few miles away. The North American Coal Corporation’s Red Hills Mine is just a few miles away, in Ackerman, MS.
I moved the radio to the other side of parking lot at the top of Little Mountain and things settled down nicely. I then could hear some actual sferics, but they were quite distant I'm sure - the weather in the southeast is now very calm so I figured it was from some thunderstorms in the Midwest. I never heard any whistlers or anything quite so dramatic as what McGreevy has recorded, but I did hear insects flying near the antenna. McGreevy notes that, "this effect is caused by electrostatic discharges each time the insect's wings flap".
Later I moved to another location on the Natchez Trace, and tried again. This time there was quite a bit of power line hum; I was sitting in my car with the antenna propped on the plastic side-view mirror enclosure and the radio resting on my left bare leg. After I placed my hand on the side of the car outside the hum disappeared entirely. Ahh...properly grounded, I think. Then faintly I hear what sounds like an alarm clock beep beep beeping just above the noise floor. I'm not sure what it was, but I timed and counted and came up with between 220 and 240 beats/beeps per minute. After about 10 minutes it abruptly stopped. I heard more insects too, and more distant lightning sferics.
I'm looking forward to spending more time with this radio and learning more about natural ELF and VLF emissions. It suits me well, as I enjoy spending time outdoors and in remote places.