Chapter 6 – Electronic Circuits &
Chapter 7 –Radio Signals

Building on (and with!) the components and principles covered in the previous two sections, your studies now move to constructing and using the circuits that make up a radio.  This set of resources will help explain how these circuits work and how they create the signals you hear on the air.

Schematics and Circuit Diagrams

• How to Read Circuit Diagrams, Part I - this may be old, but it's accurate!
• How to Read Circuit Diagrams, Part II

Amplifiers and Other Circuits

• Hands-On Radio – a series of tutorials that covers many simple circuits
• Load lines– additional graphical explanation of load lines
• Oscillators – the list of Electrical Oscillators covers the types you’ll encounter on the Extra exam
• Filter – a number of resources on filters of all types

Mixers, Modes, and Modulation

• Mixers – more information about frequency mixers and their operation
• Wikipedia entry on Modulation- a comprehensive review of modulation
• ARRL Technical Information Service - plenty of articles and links about AM
• Williamson Labs AM illustration page - animated page showing how AM works
• AMfone - a Web site about AM operating on the HF bands
• Williamson Labs SSB illustration - animated page showing how SSB works
• Wikipedia entry on Single Sideband - in-depth treatment with the theory
• Understanding FM Transmitters - a QST article about FM
• Williamson Labs FM illustration page - animated page showing how FM and PM work
• Wikipedia entry on Frequency Modulation - in-depth treatment with the theory
• Phase-Locked Loops – an overview of PLL operation
• PLL Tutorials – several detailed tutorials on PLL (advanced)
• Direct Digital Synthesis – an overview of DDS operation
• Amateur Fast-Scan TV – articles on ATV
• Amateur Slow-Scan TV – articles on SSTV

Digital Modes

• ARRL TIS Digital Mode Information - information on most popular modes  
• ARRL’s HF Digital Handbook - all about digital operating on the HF bands

Digital Signal Processing

• ARRL TIS page on DSP – tutorials and applications on Digital Signal Processing
• Sampling – a more detailed treatment of the mechanics of sampling waveforms for processing

Test Equipment

• Oscilloscope tutorial – a graphical introduction to the oscilloscope
• Test Equipment – a number of articles and projects concerning test equipment

Receivers

• The ARRL Handbook – the Handbook has a good section on receiver performance

ARRL Interference Resources

• ARRL Technical Information Service (TIS) - numerous Web resources and magazine articles on technical topics of interest to all hams
• ARRL EMI/RFI Resources - a number of resources for managing interference of all types
• FCC TV Interference Handbook - the FCC’s guide to managing interference to television receivers
• The ARRL RFI Book - helpful information for preventing and solving RF interference problems