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(Sales of the WR-3 receiver and the CD's fund this website and expeditions - thanks for your support! Steve McGreevy)
The following page and links contain information about the popular WR-3 hand-held VLF receiver designed for the monitoring of naturally-occuring ELF-VLF radio phenomena, such as whistlers, dawn chorus, the great vriety of other natural VLF radio phenomena, and lightning-storm atmospherics.
Natural ELF-VLF radio emissions vary in characteristics from place to place at any given time when they are occurring. Whistlers occurring loudly in one location may sometimes sound considerably different at another location just several hundred miles or kilometres apart, and chorus or "risers" may be head in one location (especially in more northern locales) while whistlers (fallers) are being heard strongly in another locale (usually more southerly). Thus, the natural radio sounds you may hear near your home location will differ somewhat from somebody elses, making for interesting comparisons. This is why it can fascinating to coordinate with a friend or collegue with simultaneous listening
Secondly, the variety of natural radio emissions is infinite - there are the "common" sounds you can hear with a receiver, but sometimes, surprising "uncommon" sounds to receive. This is more so as we are within solar-maximum over the years 2000 - 2002, and predicted maxima of magnetic storms in 2002 and 2003.
The popular-selling Model WR-3 is a sensitive, hand-held E-field" receiver designed for monitoring fascinating natural VLF radio phenomena in the 0.2-10 kHz (200-11,000 Hz) radio frequency range, where for the most part, no man-made radio signals exist!
Down at these low radio frequencies, you can hear a great variety of naturally-occurring ELF/VLF radio signals , such as "Whistlers" "Tweeks" "Auroral Chorus" "Dawn Chorus" "Risers" "Wavering-Tones," "Hiss," and other intriguing radio phenomena which this receiver has been specifically designed to receive.
Natural ELF/VLF radio emissions, first heard on long-distance telegraph lines in the 1880's, are produced by Earth's lightning storms, Auroral displays, and Earth's magnetic envelope surrounding the planet, called the "magnetosphere." Since the majority of natural VLF radio signals originate from the within the magnetosphere, they are very sensitive to geo-magnetic conditions and can tell scientists a great deal about what is happening with the Earth-Sun environment, particularly as an amazing amount of Natural Radio emissions are generated during magnetic storms. All of these radio phenomena are audible most strongly in mid-to-upper latitudes of the northern or southern hemispheres, between 30 to 60 degrees north or south.
When geo-magnetic storms happen, they cause Aurora (the Northern and Southern Lights) which in turn generate the musical, bird-flock tweeting or bizarre dog-bark sounds of "Chorus," which you can hear very well with the WR-3/WR-3E. If you live far enough north or south, you can watch Aurora dance in the sky and also LISTEN to their interesting VLF radio sounds with these receivers. Movements of the aurora (especially the pulsating type occurring past the peak of typical auroral displays) are usually synchronized with their changing VLF radio sounds--it's amazing! Those fortunate to be in areas where aurora is frequent will enjoy great DAYTIME natural VLF radio sounds too.
Sunrise and an hour before can be a rewarding time to listen for Chorus, which is why it is often referred to as "Dawn Chorus." Dawn Chorus can take on the sounds of bird-flock tweeting or lower pitched sounds similar to dog or seal barks. "Hiss" and "Wavering/wandering-tone emissions" (or a combination of the above phenomena) can also be heard during some magnetic storms with the WR-3.
Lightning storms have their own incredible effect on Earth's magnetic field. A million lightning strokes occur worldwide every day from thousands of storms in progress at any given time. Lightning-stroke radio energy is greatest between below 10 kHz and triggers natural radio sounds called "Whistlers." This is because lightning-storm radio energy is capable of being ducted within Earth's magnetic field from one polar hemisphere to the opposite hemisphere; undergoing an effect researchers call "dispersion" as well as being amplified and sustained during its long 25,000 mile journey between the hemispheres. This unusual form of radio wave propagation creates falling-note sounds called "Whistlers." Whistlers can range in sound from very pure and flute-like notes or sound swishy and breathy. On some mornings (the best time to listen), there can be a whistler every second (or even more)!
The WR-3 has been highly praised by both individual listeners (hobby and amateur scientists) and also by several university staff, and has been designed to make monitoring of natural radio as easy and convenient as possible as they both only require a short 30 to 60 inch whip-antenna (BNC-type base mount, optionally included). The WR-3 has a headphone jack for "mini-stereo" style stereo headphones (1/8-inch/3.5 mm plug). Since most listeners already have their own preferred kind of headphone, headphones are not supplied, thus we can keep the price lower.
Because the WR-3 converts the 0.2-11 kHz ELF/VLF frequencies directly to audio signals in the headphones, they require no tuning, mixer or i.f. circuitry. The WR-3 has one control knob: audio GAIN and Power ON/OFF. The optional telescoping whip antenna mates tightly onto a male BNC-type connector. The ultimate in portabliity, this receiver (with antenna detached) fits into your shirt pocket.
A very detailed Listening Guide is included with each receiver on a compact-disc in both HTML format for web browsers, and also in PDF for viewing with the free Adobe Acrobat Reader. Additionally, the HTML version can be viewed online and printed or downloaded. The Listening Guide gives a good overview of "Natural Radio" listening and has a list of additional references and scientific publications where you can refer to if interested in reading further about natural radio phenomena. A 60 minute demonstration audio CD, entitled "Auroral Chorus" is full of a variety of examples of natural radio phenomena is included with each receiver. (details of CD are in the WR-3 Listening Guide).
Stephen P. McGreevy, N6NKS, 03 September 2001
S. P. McGreevy Productions
P.O. Box 928, Lone Pine, CA 93545-0928 USA
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