Imagine a time when radio was just some experiment in the labs or basements of inventors trying to figure out the phenomenon of sounds being heard over the air. Seems a bit of a stretch? During the period of 1904 to 1915 the first types of radio transmitters were developed which produced continuous sinusoidal waves: the arc converter (Poulsen Arc) and the Alexanderson alternator. These slowly replaced the old damped-wave spark gap transmitters. Besides having a longer transmission range, these transmitters could be modulated with an audio (voice or music) signal to transmit sound by amplitude modulation (AM) radiotelephony. So … The post A Crystal Radio Kit for TEOTWAWKI – Part 1, by Mike in Alaska appeared first on SurvivalBlog.com.