Chapter 9 – Antenna and Feed Lines &
Chapter 10 – Topics in Radio Propagation

Antennas and propagation are the heart of what makes radio a unique form of communication. Amateurs enjoy building and experimenting with antennas, one of the most active areas of experimentation. Amateurs have also excelled over the years in ferreting out new and useful modes of propagation.  Resources for these two sections of the Extra Class exam will support you as you study.

Antennas

• How Antennas Work - a collection of antenna articles
• The ARRL Antenna Book - the amateur’s standard reference for information on antennas, feed lines, and propagation
• Antennas - Service and Education - L.B. Cebik W4RNL’s informative Web site on antennas
• Antennex - antenna experimenter Web magazine

Transmission Lines

• ARRL TIS Transmission Lines - articles and references about feed lines and SWR
• ARRL TIS Antenna Tuners - information on impedance matching equipment

Propagation

• Propagation - several introductory and basic propagation articles
• RSGB Propagation - thorough list of resources from the Radio Society of Great Britain
• AC6V Propagation Resource List - compilation of propagation links and resources
• Propagation Prediction Software - software package list on the AC6V Web site

Beacon Stations

• NCDXF Beacons - the Northern California DX Foundation maintains a world-wide system of beacons for hams to use for checking HF propagation
• Directories of Beacon Stations

Solar Activity and Geophysical Information

• Spaceweather - what’s going on around the Earth
• HF Radio - real-time information and predictions