K8TND Sfer-X Receiver – $25
Available soon when you see the PayPal button
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 influence 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 supplied 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. Our design incorporates a twin “T” notch 60 Hz filter to eliminate the majority of the AC hum generated from the power generated domestic grid. 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 attached 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.
The normal tools required, are a soldering iron with a small tip, rosin core solder, small side cutters. This kit can be assembled in an evening or maybe a little longer if you are explaining as they build it. Please let us know how you do with this project. All comments are carefully reviewed.
Builders will need a 9V battery and earbuds.
Click here for the assembly manual
Excellent listeners guide contained here:
Some interesting reference urls to explore:
https://vlfstanford.ku.edu.tr/research_topic_inlin/introduction-vlf/
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL052123
https://www.youtube.com/watch?v=FeuI8AJMIxU
https://www.youtube.com/watch?v=fdj8p6c2lew
https://www.auroralchorus.com/
https://en.wikipedia.org/wiki/Whistler_(radio)