K8TND Sfer-X Receiver
Not all the radio signals (electromagnetic radiation) around us comes from direct human activity. There is a world of ELF/VLF emissions generated from the earth and atmosphere itself.
Cliff Donley, (K8TND), has designed another fun and entertaining kit to build. This cool little receiver will introduce you to the exciting world of Sferics, Tweeks, Whistlers, and other VLF/ELF phenomenon. Or, you may be an experienced builder that would like to introduce and mentor a youngster into radio and electronics, building a kit. With the K8TND Sfer-X Receiver you can explore the little known world of strange low frequency signals. The Sfer-X is a sensitive receiver that detects very low frequency electromagnetic propagation with a simple one foot long wire antenna. A lot of research is being conducted into lightning and even into sferic emissions as a precursor to earthquakes. A simple Google search will reveal a wealth of blogs and websites.
Now, there’s also a lot of other COOL things to listen to, such as the static produced by car tires on a dry day, the electrical noise made by just walking or even the sound made by a bee’s wings fluttering. One thing to keep in mind is that you will also hear AC hum in the headphones until you get far away from houses or electrical power lines, preferably at least a mile. Some of the software listed below will remove most of the AC hum from your recordings. This small hand held 1.50″ x 4.20″, (38.1mm x 106.7mm) through hole kit is a self contained receiver powered by a standard on board 9 volt battery. You can listen to signals with a pair of earbuds or record them, and feed the audio into a sound card for a graphic representation of the received signals, as described in a YouTube link below. There are programs to filter (Audio Hijack, for Mac), (Total Recorder, for Windows), and to display graphically your signals, (Ispectrum for Mac), and (Waterfall Spectrum Analyzer for Windows), or just listen. This kit can be assembled in an hour or so, depending on your experience, with the normal kit tools. Builders will need a 9V battery and earbuds.
Click here for the assembly manual
Some interesting reference urls to explore:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL052123
https://www.youtube.com/watch?v=FeuI8AJMIxU
https://www.youtube.com/watch?v=fdj8p6c2lew
no images were found