ON7YD, longwave, 136kHz, antennas Page 1 of 51 ON7YD Antennas for 136kHz About this page : The main object of this page is to provide information. It has been deliberately kept simple, no fancy and flashy tricks, in order to achieve maximum compatibility for the different browsers and to allow fast downloading. Any comments and/or suggestions are welcome at :
[email protected] last updated on 8 July 2004 Index 1. Introduction 2. Short vertical antennas 1. Vertical monopole antenna 2. Short vertical monopole 3. Vertical antenna with capacitive toploading 4. Umbrella antenna 5. Capacitive toploading of single-tower antennas 6. Spiral toploaded antenna 7. Vertical antenna with inductive toploading 8. Vertical antenna with capacitive and inductive toploading 9. Vertical antenna with tuned counterpoise 10. Meander antenna 11. Antenna with multiple vertical elements 12. Using a non isolated antenna-tower as LF-antenna 13. Antennas with a long horizontal section 14. Helical antenna 15. Short vertical dipole 16. Why a horizontal dipole is a rather unefficient antenna on LF 17. Safety precautions 18. Bringing a short vertical monopole to resonance 1. Loading coil 2. Coil losses : the Q-factor 3. Variometer 4. Tapped coil 5. Impedance matching 6. Bandwidth considerations 3. Efficiency of antenna systems on LF (short vertical antennas) 1. Antenna system 2. Efficiency 3. Antenna system efficiency, antenna directivity, ERP, EIRP and EMRP 4. Optimizing the antenna system efficiency 5. Enviromental losses 6. Ground loss 1. Type (composition) of the soil 2. Frequency 3. Shape and dimensions of the antenna 4. Radial system and ground rods 4. Measuring ERP on LF http://www.qsl.net/on7yd/136ant.htm 12/19/2006 ON7YD, longwave, 136kHz, antennas Page 2 of 51 1.