Lesson 9
Test Equipment and It’s Uses Earlier levels of your license focused on basic electronics test equipment like multimeters. Those measure the performance of different circuit components. As an Amateur Extra you are expected to know more about designing and testing circuits. That necessitates understanding a broad range of test gear. On a multimeter, voltage testing […]
Lesson 10
Receiver Performance Characteristics A good receiver can help you pick out weak signals among other stronger ones on the band. Want to efficiently pick out weak signals? Knowing the characteristics of receiver performance will help. The characteristic called capture effect takes place with FM receivers. The receiver will generally lock on or “capture” the strongest […]
Lesson 14
Semiconductor Materials and Devices Modern radios depend on components like diodes and transistors. They manage the flow of current in a circuit and do things like switching. These are part of a family of components called semiconductors. Like the name implies, semiconductors are partially conductive to electricity. Their conductivity falls between an insulator and a […]
Lesson 11
Interference Outside the Radio Signals harmful to your radio reception might not be coming from your radio gear. They may be sneaking out of other electrical signals in your home and neighborhood. Personal computers are a particular risk for unwanted noise. A PC may introduce the appearance of unstable modulated or unmodulated signals at specific […]
Lesson 30
RF Radiation Hazards You have a responsibility to protect yourself and others from RF radiation hazards. RF radiation from amateur radio equipment could heat up human tissue. That can cause harmful RF burns or tissue damage. RF exposure evaluations help keep everyone safe. That’s partly why it’s included in all three license exams. In 2023, […]
Lesson 28
Transmission Lines It’s time to connect your antenna to your transceiver. That is done using transmission lines, frequently called feedlines. We’ll focus on two types of transmission line here. We’ll use the term “coax” to refer to a coaxial cable with a plastic dielectric insulator. The other type of feedline we’ll cover is ladder line. […]
Lesson 16
Inductors and Ferrites Remember how an inductor works. It’s typically an insulated wire wound around a core that stores energy in a magnetic field. Think of wrapping a wire around a nail – that would create a basic inductor. In this case the nail would be the core. Wire wound inductor There are several different […]
Lesson 17
Logical Operation The next few lessons go deep into electronics principles. We’ll be using some schematics to illustrate these circuits and their principles. To make your studies easier, know that only the schematics that have a figure number are on the exam. You’ll see those, like E7-1, come up in a later lesson. In an […]
Lesson 18
Modulation and Demodulation In radio communications, there are two primary components of the transmitted signal. They are baseband signal and the modulated signal. Let’s look at an example of an AM signal that might go out over a local broadcast station. We’ll call it “AM 1000 – WHRP.” Engineer Maria would set up the transmitter. […]
Lesson 19
Filters In the digital or analog RF environment, there will be interference and other noise to deal with. That is why filters are a very useful tool. They help bring in weak signals or get only the signal you want to hear at that moment. Filters narrow the spectrum the radio is working with. They […]
