This is a collection of articles that form a text book on designing crystal radios.  The primary focus is to illustrate to engineering students how to apply concepts of engineering to solve a problem.  It takes a lot of in-depth research to be good at what one does.  The main part of this book deals with understanding the required concepts to build a good basic crystal radio.  Advanced concepts (to be written and posted last) will deal with a number of improvements that can be made to the basic design.

The following are links to the pdfs for each chapter.  If a link is not active then the chapter is not complete -- I am working as fast as I can to finish and post those so check back often.  The following is only a guide for now.  As the book develops I will likely add chapters or merge some chapters.  Many of the chapters are still incomplete and more material will be added as I have time.  I am trying to post all I have at the moment, however incomplete, so that students in the communications class, EE421, can use this to help with their crystal radio projects.

Inductor Design Spreadsheet  This is an Excel spreadsheet that guides you through the process of designing an inductor.  

title.pdf

introduction.pdf

component_sources.pdf

rf_field_strength.pdf

antenna_and_ground_system.pdf

simple_radios.pdf

mathematical_model_of_wire_antenna.pdf

resonant_circuit.pdf

antenna_matching.pdf

designing_inductors.pdf

tapping_inductors.pdf

diode_detectors.pdf

audio_transformer.pdf -- new as of April 13, 2008

headphones.pdf

speakers.pdf

loop_antennas.pdf -- new as of April 17, 2008

a_simple_crystal_radio.pdf

advanced_topics.pdf

A chapter on making various measurements of your system is planned.  Some other chapters or additional information is planned to connect all the chapters together smoothly.  Right now the connections are rough -- but this is a work in progress.