Technical topics — National Amateur Radio Alliance

You can operate for years without this material and many people do. It is also what turns the hobby into an education: the difference between owning a radio and understanding a system.

Related topics: the station for the practical side, and reference for tables and definitions.

In this section

RF exposure and safety Every station must have an exposure evaluation on file. Here is how to do one.

Propagation Why signals travel further at night, and how to predict it.

Electronics basics The handful of formulas you actually need.

Decibels and power Why 100 watts is only one S-unit better than 25, and other useful arithmetic.

Modulation and modes AM, FM, SSB, CW and what the differences cost.

Receiver performance What sensitivity, dynamic range and roofing filters mean when you read a review.

Antenna theory Gain, patterns, polarization and matching.

Space weather Solar flux, sunspots, the A and K indices, and what they mean for your next contact.