Natural Radio - Tune In to the Music of the Spheres

What can you hear out there?

From Plate Tectonics to Particle Physics, Natural Radio is any electromagnetic energy which occurs in Nature. Such phenomena have been around since before we had the technology to detect them. Here are some examples:

A true story with a moral:

In 1931 radio engineer Karl Jansky, while studying radio background noise, reported an extraterrestrial radio source in the constellation Sagittarius. Professional astronomers ignored Jansky's report, but an Illinois ham radio operator, Grote Reber, was fascinated. He was turned down for a job working with Jansky, but in 1937 Reber constructed home built receiving equipment and a 31 foot dish antenna. By 1941 Grote Reber had made the first radio map of our Milky Way galaxy at a frequency of 160 MHz. Today Grote Reber's original radio dish telescope is a historical monument in Green Bank, West Virginia. Before all the slick mega budget research and development phase of just about anything, there are always a few anonymous creative folks with too much time on their hands who sit around tinkering with impractical gadgets to do improbable things which nobody else wants done. These are the true pioneers.

Epilogue to a true story:

In the movie Contact, Jodie Foster plays the credulous scientist whose early training in ham radio helps her step outside the envelope and first recognize signals from an extraterrestrial civilization. When Warner Bros filmed Contact at the VLA radio astronomy observatory in Socorro, NM, they were assisted and advised by employees of the observatory. The ham radio operators at the VLA contacted Grote Reber, now very aged and living in Tasmania. Grote Reber gave permission for Jodie Foster to use his original radio callsign in the movie, the ham callsign he used while pioneering the science of radio astronomy in his backyard sixty years before.

But what if its NOT natural ?

The Search for Extraterrestrial Intelligence (SETI) is an attempt to detect Electromagnetic evidence of intelligent life besides our own. You can help by downloading the SETI At Home Screen Saver which fetches SETI recordings off the net and processes them while you PC is idle.


NASA Inspire Project Participate in NASA joint coordinated experiments between the space shuttle and volunteer listeners on the ground. These space physics and ionosphere radio experiments are conducted to help us better understand the Earth's natural electrical environment. The Soviet Union conducts similar experiments under their project INTMINS. Participation in INSPIRE and INTMINS is open to volunteers of all nations.

Natural Radio Projects

Loop Theory Primer A primer on the theory of electrically small loop receiving antennas published on the Longwave Club of America web site. This document rigorously derives the response of a receiving loop under conditions where the loop is very small compared to a wavelength, and operated as a broadband receive antenna below resonance such as in ULF, geological exploration and geomagnetics. Also refer to this handy diagram of loop shapes and aperture factors.
Octoloop LF Receive Antenna Octoloop receive antenna for 0.00003 MHz to 0.2 MHz. Yes, thats right, your ears cover most of that range, which makes trivial receiver designs possible. Complete construction details of the OctoLoop were published HERE on the LWCA web site and were also published in The Lowdown, the journal of the Longwave Club of America. This cheap and easy 50 turn shielded loop design is great for nulling the nasty noise which plagues the bands below 0.5 MHz. I have used it to recieve airport beacons over 2000 miles away, and to listen to natural radio even in suburban areas. This loop antenna is highly balanced and shielded to yield deep directional nulls, which allows a noise or interference source to be nulled out of the receive signal. New 200 turn version includes tickler windings for those who like to experiment with tuning and regeneration.
Octoloop LF Receive Antenna Due many requests, here is a wiring diagram as well. The number of conductors is not important. Also see 200 turn version for alternative hookups which allow tuning and/or regeneration.

Also see original magazine article for construction notes and tips.

SpooLoop LF Receive Antenna SpooLoop receive antenna for 0.00003 MHz to 0.2 MHz. This quick and dirty receive loop design was a last minute compact, rugged antenna to be tossed into an overnight bag for an unexpected business trip near the South Pole. The antenna works better than expected, so here it is.
DC - 300 kHz Low Noise Preamplifier The LF LNA, an Ultra-low noise, high CMRR and excellent balance are key features of this receive preamplifier covering DC to 300 kHz. This very simple circuit uses a biomedical instrumentation amplifier with an equivalent input noise of only 0.009 microvolts per root Hz, and a 1/f noise below 0.28 uV rms total from 0.1 Hz to 10 Hz.. Excellent companion to the OctoLoop or SpooLoop, this preamp and a Radio Shack pocket speaker amp can hear magnetic ripples from a mechanical watch ticking a few meters away, and an automobile a mile away.
Mk IV ULF/ELF Receiver The MK IV ELF/ULF software tuned receiver. This is a work-in-progress; results from my Mk IV design encourage me to proceed further. The Mk IV uses an analog front end to condition the signal, a dvm with serial interface to acquire the data, custom software to make a Microsoft .wav file, and shareware to post-process the files. The LONGWAVE BBS (706-672-0360) has some design info on my Mk III and my Mk IV receivers. This highly sensitive front end for a centertapped loop combines the ultra-low noise preamp with passive and active filtering.
60 Hz passive notch filter This 60 Hz passive notch filter improves the dynamic range of DSP and SSP receivers by preventing overload of the analog front end by 60 Hz hum. Passive design with DC coupling incurs no error, no increase in noise floor, and no degradation of dynamic range.
Cloud Charge Monitor Easy Homegrown electrometer by Charles Wenzel can detect changing charges of passing clouds. Simpler than a field mill, no moving parts, build it in a weekend !

Quake Logo

Quake Radio ?

From Plate Tectonics to Particle Physics, Natural Radio is any electromagnetic energy which occurs in Nature.

In the range of 0 to 10 Hz, we 'hear' or sense waves from the internal groans and creaks of the Earth, the solar wind howling around the Earth's magnetosphere, magnetic storms, and a host of unknown phenomena. Although these are infrasonic, below human hearing, you can speed up a recording to bring them within range of human hearing.

One of the hottest research topics in this part of the electromagnetic spectrum is the possibility of earthquake precursors that could provide an early warning and save lives. The National Earthquake Information Center at the United States Geological Survey provides this and other near-real time maps, maintains searchable databases and other resources, a veritable Mecca of seismology.

Near-Real Time Earthquake Map from
National Earthquake Information Center,
United States Geological Survey

Fields and Waves in this region of the spectrum include magnetometers and electrometers for magnetic and electric fields to DC, and seismographs and gravimeters for mechanical and gravity waves.

Future Projects

You can tell by now I like strange and unlikely projects. Some of the ones below may survive to completion.

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