11.1 INTRODUCTION 111.2 DIELECTRIC PROPERTIES OF AN IONIZED MEDIUM11.3 PROPAGATION IN A MAGNETOIONIC MEDIUM11.4 IONOSPHERIC PROPAGATION CHARACTERISTICS11.5 IONOSPHERIC SOUNDING11.6 THE SECANT LAW11.7 TRANSMISSION CURVES11.8 BREIT AND TUVE'S THEOREM11.9 MARTYN'S THEOREM ON EQUIVALENT VIRTUAL HEIGHTS11.10 MUF, “SKIP” DISTANCE, AND IONOSPHERIC SIGNAL DISPERSION11.11 EARTH CURVATURE EFFECTS AND RAY-TRACING TECHNIQUES11.12 IONOSPHERIC PROPAGATION PREDICTION TOOLS11.13 IONOSPHERIC ABSORPTION11.14 IONOSPHERIC EFFECTS ON EARTH–SPACE LINKSREFERENCES