How to Use These Supplements
These items are organized to match the General License Course chapter and lesson structure. Peruse them after completing each lesson to deepen your understanding. Open any chapter below to explore its resources.
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Before We Begin...
Introductory review & background resources
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Ham-Speak: Learning the LingoArticle
Common ham radio jargon, abbreviations, and Q-codes — a useful review before diving into General level material.
Common Ham Radio TermsPDF
A reference sheet of common ham radio terms and abbreviations for new operators.
Loads of ModesArticle
Overview of transmission modes relevant to General class — AM, SSB, CW, digital, and more.
Binary Digital Logic Basics (YouTube)Video
Introduction to binary logic gates and digital circuit fundamentals relevant to General hamtronics topics.
Electric Current Direction (YouTube)Video
Explanation of conventional current vs. electron flow — a foundational concept for circuit analysis.
AC vs DC (YouTube)Video
The difference between alternating current and direct current — how each behaves in circuits.
Time & Frequency Domain Signal ViewsArticle
Understanding how the same signal looks different when viewed in the time domain vs. the frequency domain.
Time & Frequency Domain FFT AnalyzerApp
Explore and view signals in both time and frequency domain visualizations.
A Simple View of ResonanceArticle
Intuitive explanation of resonance in LC circuits — the foundation of tuned filters and antenna behavior.
73 = Best Number (YouTube)Video
Fun history of the traditional ham radio sign-off "73" — its telegraph origins and meaning.
1
Rules & Regulations
3 lessons — Bands/privileges, special services, DX & details
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1.1
Bands and Privileges
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Transmitting Privileges (T1E04)Article
What third-party and unlicensed operators may transmit under your supervision as a licensed General.
Volunteer Examiner Coordinators (FCC)External
FCC list of accredited VECs that administer amateur radio license examinations.
CERT Program (FEMA)External
Community Emergency Response Team — FEMA's training program for community disaster preparedness volunteers.
RACESExternal
Radio Amateur Civil Emergency Service — the FCC-authorized amateur emergency communications service.
ARES (ARRL)External
Amateur Radio Emergency Service — the ARRL's volunteer emergency communications program.
Volunteer Monitor Program (ARRL)External
The ARRL Volunteer Monitor Program — licensed hams who help monitor on-air operating practices.
Worldwide Beacons (NCDXF)External
The NCDXF/IARU International Beacon Project — 18 HF beacons on 5 bands helping operators assess propagation worldwide.
1.2
Special Services
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Working DX ContactsArticle
Practical techniques for making DX contacts on HF — calling procedures, pile-up tactics, and split operation.
Allowable International ContactsArticle
Which countries permit third-party traffic and international contacts with US amateur stations.
Part 97 Regulations (eCFR)External
Official FCC Part 97 Amateur Radio Service rules — the complete regulatory text governing US ham radio.
ITU HomeExternal
International Telecommunication Union — the UN agency coordinating global radio spectrum and international regulations.
IARP Info (ARRL)External
International Amateur Radio Permit — allows US hams to operate in participating countries.
CEPT Info (ARRL)External
CEPT agreement — allows US General and Extra class hams to operate in European countries without a local license.
US Third-Party Nations (ARRL)External
Countries with which the US has third-party traffic agreements for ham radio communications.
Maximum Antenna Height (G1B01)Article
FCC height limits for amateur radio antenna structures and notification requirements for taller installations.
Morse Code Practice (W1AW)External
ARRL's W1AW station schedule for code practice transmissions — great resource for CW learning.
1.3
DX and Details
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No additional supplements for this lesson.
2
Operating Your Radio
3 lessons — Good amateur practice, operating techniques, CW
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2.1
Good Amateur Practice
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HF Ops: The Difference with HFArticle
How HF operating differs from the VHF/UHF work Technicians are used to — propagation, procedures, and etiquette.
Practical Signal ReportsArticle
How to give and receive meaningful RST signal reports rather than the obligatory "59" exchange.
Phonetic Alphabet AlternativesArticle
Alternative phonetic alphabets used in ham radio — when and why some operators use non-standard phonetics.
Considerate Operator's Guide (ARRL PDF)PDF
ARRL's guide to courteous on-air operating practices — essential reading for HF operation.
2.2
Operating Techniques
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Split Mode Operations (G4A03)Article
How and why to operate split — transmitting on one frequency while listening on another for DX pile-ups.
Simplex, Duplex, Offset, SplitArticle
Clarifying the differences between simplex, duplex, offset, and split operating modes.
Azimuthal Projection Maps (NS6T)External
Generate a custom azimuthal equidistant map centered on your location — shows beam headings to all parts of the world.
2.3
CW (Morse Code)
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Zero Beat (G2C06)Article
How to zero-beat a CW signal — matching your transmit frequency to the station you're calling.
Learn CW Online (LCWO)External
Free online Morse code training using the Koch method — the most effective approach for learning CW.
3
Digital Modes
3 lessons — Digital basics, FSK modes, packet & other modes
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3.1
Digital Mode Basics
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Symbol Rate and History (YouTube)Video
The history of digital communications symbol rate — from telegraph to modern ham radio digital modes.
3.2
Frequency Shift Keying Modes
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FT8 Starting Guide (YouTube)Video
Step-by-step guide to getting started with FT8 — the most popular weak-signal digital mode in ham radio today.
FT8 Operations Example (YouTube)Video
Demonstration of a complete FT8 QSO — software setup, calling, and completing the contact exchange.
RTTY EnthusiastsExternal
Resources for radioteletype (RTTY) operation — one of the oldest digital modes still actively used in ham radio contests.
RTTY Beginners Tutorial (IW5EDI)External
Comprehensive beginner's guide to RTTY operation — software, setup, and getting on the air.
3.3
Packet & Other Digital Modes
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PSK31 Varicode (G8C08)Article
How PSK31's Varicode encoding achieves efficiency on narrow bandwidth using variable-length character codes.
PSK31 Specification (ARRL)External
The official PSK31 technical specification — modulation details, Varicode table, and protocol definition.
BPSK & QPSK ModulationExternal
Technical explanation of Binary and Quadrature Phase Shift Keying — the modulation underlying PSK31 and other modes.
Digital Voice PrimerArticle
Introduction to digital voice modes — D-STAR, DMR, Fusion/C4FM — how they work and how to get started.
AREDN Mesh NetworkExternal
Amateur Radio Emergency Data Network — the current standard for amateur radio IP mesh networking for emergency communications.
Auto Repeat Query (ARQ)Article
How ARQ error-correction systems automatically request retransmission of corrupted data packets.
Winlink Email ServiceExternal
Global amateur radio email system using HF radio — widely used for emergency communications when internet is unavailable.
VARA ProtocolExternal
VARA — a high-performance HF/VHF modem protocol used with Winlink for efficient digital radio communications.
4
Propagation
3 lessons — Solar activity, ionosphere, operational impacts
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4.1
Solar Activity
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Sunspots & PropagationArticle
How solar activity and the sunspot cycle affect HF radio wave propagation through the ionosphere.
Variable Propagation Conditions (G3A10)Article
Why HF propagation varies dramatically throughout the day, season, and solar cycle — and how to predict it.
SpaceWeather.comExternal
Daily solar weather — sunspot numbers, solar flux index, geomagnetic conditions, and band opening forecasts.
Sunspots & HF PropagationExternal
Solar cycle tracking and HF propagation forecasting resource for ham radio operators.
4.2
Ionosphere & Magnetosphere
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D-layer AbsorptionArticle
How the ionospheric D-layer absorbs HF signals during daylight and why certain bands go quiet during the day.
DX Techniques (E3A06)Article
Advanced techniques for maximizing DX contact success — gray line, long path, and optimal timing strategies.
4.3
Operational Impacts
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Skip Signal FadeArticle
What causes skip zone fading and why distant stations can sometimes be stronger than nearby ones.
Propagation Types (T3C04)Article
Overview of over-the-horizon propagation modes — sporadic-E, troposcatter, and others enabling VHF DX.
NVIS OperationsArticle
Near Vertical Incidence Skywave — the HF propagation mode ideal for regional communications within 300 miles.
Chordal Hop PropagationArticle
How chordal hop propagation allows signals to travel very long distances with less loss than conventional multi-hop skip.
DX Maps — Contact ReportsExternal
Real-time map of ham radio contacts being made worldwide — see current propagation conditions visually.
WSPRnet MapExternal
Weak Signal Propagation Reporter network map — shows real-time WSPR beacon reception paths worldwide.
5
Processing Signals
3 lessons — Signal characteristics, transmitting, receiving
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5.1
Signal Characteristics
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AM SimulatorApp
Simulates amplitude modulation of an RF carrier by a baseband signal such as audio — see AM modulation in action.
FM SimulatorApp
Simulates frequency modulation of an RF carrier — watch how audio input causes the carrier frequency to deviate.
Understanding Single SidebandArticle
Clear conceptual explanation of SSB — how it suppresses the carrier and one sideband to concentrate power efficiently.
Carson's Rule (G8B06)Article
Carson's Rule for estimating FM signal bandwidth — a key formula for understanding occupied spectrum.
FM RepeatersArticle
Review of FM repeater operation — useful context for understanding FM signal characteristics.
Digital Signal ProcessingArticle
How DSP improves modern ham radio receivers — filtering, noise reduction, and demodulation in software.
5.2
Transmitting Signals
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Direct Digital Conversion (E7F01)Article
How direct digital conversion transceivers work — ADC/DAC in the signal path enabling software-defined radio.
I-Q ModulationArticle
Quadrature (I/Q) modulation explained — the technique used in modern SDR transceivers to generate and demodulate signals.
Oscillator Basics (YouTube)Video
How oscillator circuits generate stable radio frequency signals — LC, crystal, and VCO types explained.
Direct Digital Synthesis (YouTube)Video
How DDS generates precise frequencies digitally — used in modern ham radio VFOs and signal generators.
SSB Bandwidth AdvantageVideo
Video explaining the advantages of SSB over AM for HF voice communication.
SSB Audio Required for PowerArticle
Why an SSB transmitter produces no RF output without audio input — understanding PEP and average power.
5.3
Receiving Signals
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QRM and Receive Filtering SimulatorApp
Interactively explore realistic SSB and CW receive filter effects with interfering signals in the band.
Filter SimulatorApp
Explore various filter shapes and bandwidths applied to stock and custom-recorded audio signals.
SSB Receive Filters (T4B09)Article
How receiver IF bandwidth filters affect SSB signal quality and selectivity in crowded band conditions.
Receiver Signal DiscriminationArticle
How receiver selectivity and dynamic range determine a radio's ability to reject unwanted signals.
Direct Digital Conversion (E7F01)Article
How direct-conversion receivers digitize the RF signal directly — the architecture of modern SDR receivers.
Heterodyne Receiver FunctionArticle
How the superheterodyne receiver uses frequency mixing and IF stages to achieve selectivity and sensitivity.
6
Antennas
3 lessons — Theory & principles, directional antennas, SWR & matching
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6.1
Antenna Theory & Principles
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How Many Antennas Do I Need?Article
Practical answer to a common question — multiband vs. dedicated antennas for each band.
dBi vs. dBd (G9C04)Article
The difference between dBi and dBd antenna gain references and how to convert between them.
Your First Dipole Antenna (HF)Article
Building and installing a simple HF dipole — the most fundamental and versatile antenna for General class HF operation.
NVIS Antenna & OperationsArticle
NVIS antenna design and operating techniques for regional HF communications within 300 miles.
Mobile InstallationArticle
Planning and executing a ham radio mobile installation — antenna mounting, coax routing, and power connections.
6.2
Directional Antennas
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Yagi Driven Element (G9C02)Article
The role of the driven element in a Yagi antenna and how parasitic elements shape the radiation pattern.
Log Periodic Antenna (G9D06)Article
How log periodic antennas provide broadband directional gain — useful for covering multiple HF bands.
Yagi Simulation 2 (YouTube)Video
Computer simulation of a Yagi antenna — visualizing the directional radiation pattern and front-to-back ratio.
Yagi Basics (YouTube)Video
Fundamentals of Yagi antenna design — elements, spacing, and how gain and directivity are achieved.
6.3
SWR & Impedance Matching
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SWR Wave SimulatorApp
Visualize the voltage traveling waves in a transmission line and how they interact to determine SWR.
Good SWR & Antenna ResonanceArticle
The relationship between antenna resonance and SWR — when a low SWR reading indicates a well-matched antenna.
Trimming a DipoleArticle
How to adjust dipole antenna length for resonance and minimum SWR on your target frequency.
Dipole Impedance (G9B08)Article
Why a center-fed half-wave dipole has approximately 72 ohms impedance and how height affects this.
Antenna Q FactorArticle
How antenna Q factor relates to bandwidth — high Q antennas are more selective but have narrower bandwidth.
Coaxial Cable Losses (T9B05)Article
How coaxial cable loss varies with frequency and length — choosing the right cable for your HF installation.
SWR Perfect Match (T7C04)Article
What a 1:1 SWR reading means and why a perfect impedance match maximizes power transfer to the antenna.
7
Hamtronics
9 lessons — Power, components, circuits, measurement, interference
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7.1
Power and Principles
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Voltage Calculation (T5D02)Article
Worked examples of Ohm's Law voltage calculations in DC circuits.
RMS Voltage (G5B09)Article
Understanding RMS (root mean square) voltage — the effective value of an AC voltage for power calculations.
Power Calculation (G5B03)Article
Calculating electrical power using P=IE and related formulas — includes RF power and PEP calculations.
How Electricity Works (YouTube)Video
Comprehensive overview of how electricity works — from electrons to practical circuits.
7.2
Components
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Figure T1 — Circuit DiagramArticle
Component identification in the Technician exam Figure T-1 circuit — a useful review of electronic symbols.
Capacitors (YouTube)Video
How capacitors store and release electrical energy — construction, ratings, and use in RF circuits.
Inductors (T6A06)Article
How inductors work, their role in RF circuits, and how inductance relates to coil construction.
Inductors (YouTube)Video
Visual explanation of inductors — how they store magnetic energy and oppose changes in current.
Transistors (YouTube)Video
How transistors work as amplifiers and switches — the foundation of modern electronic circuits.
Semiconductor MaterialsArticle
The semiconductor materials used in ham radio electronics — silicon, germanium, and gallium arsenide properties.
7.3
Series & Parallel Components
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Series & Parallel Component CalculationsArticle
Calculating total resistance, capacitance, and inductance for series and parallel component combinations.
Series Circuits (YouTube)Video
Series circuit analysis — current, voltage drops, and total resistance calculations.
Parallel Circuits (YouTube)Video
Parallel circuit analysis — shared voltage, branch currents, and total resistance.
7.4
Impedance & Reactance
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Complex Impedance Part 1Article
Introduction to complex impedance — resistance, reactance, and the phasor representation of AC circuits.
Complex Impedance Part 2Article
Inductive and capacitive reactance calculations — how frequency affects component impedance in RF circuits.
Complex Impedance Part 3Article
Combining resistance and reactance — calculating total complex impedance and phase angle in RLC circuits.
Capacitive Reactance (G5A06)Article
How capacitive reactance varies with frequency — the formula Xc = 1/(2πfC) and its ham radio applications.
Power Factor (YouTube)Video
Understanding power factor in AC circuits — real power, reactive power, and apparent power relationships.
7.5
Power Sources
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Transformer Windings (G5C06)Article
How transformer turns ratio determines voltage transformation — calculating secondary voltage and current.
Transformer Winding Diameters (G5C16)Article
How wire diameter in transformer windings affects current capacity and efficiency.
Transformers (YouTube)Video
How transformers use electromagnetic induction to change AC voltage levels.
Bleeder Resistors (G7A01)Article
Why power supplies use bleeder resistors — safety discharge of filter capacitors and voltage regulation improvement.
Linear Power Supply (YouTube)Video
How a linear regulated power supply works — transformer, rectifier, filter, and regulator stages.
Basic Solar Power System (YouTube)Video
Setting up a basic solar power system — panels, charge controllers, batteries, and inverters for ham radio portable ops.
Small Solar Power System for RadioArticle
Practical guide to building a small solar power system for portable and emergency ham radio operations.
7.6
Amps & Tubes
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Vacuum Tubes (G6A10)Article
How vacuum tubes work and why they are still used in high-power ham radio amplifiers today.
Vacuum Tube Function (YouTube)Video
How vacuum tubes amplify signals — triodes, tetrodes, and pentodes explained with animations.
Tube Amp Overview & Tuning (YouTube)Video
Overview of a vacuum tube HF amplifier and how to properly tune the output network for your band.
7.7
ICs and Computers
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Liquid Crystal DisplaysArticle
How LCD technology works — used in transceiver displays, SWR meters, and other ham radio equipment.
Op Amps (E7G12)Article
Operational amplifier fundamentals — inverting, non-inverting, and comparator configurations in ham radio circuits.
IC Packaging (YouTube)Video
Overview of integrated circuit package types — DIP, SOIC, QFP, and how to identify them on circuit boards.
Surface Mount Technology (YouTube)Video
Introduction to SMT components and PCB assembly — used in modern ham radio equipment.
Surface Mount Facility (YouTube)Video
Tour of a PCB surface mount assembly facility — how modern electronic equipment is manufactured.
7.8
Measurement
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10 Uses for a Digital MultimeterArticle
Practical applications of a DMM in the ham shack — voltage, current, resistance, continuity, and diode testing.
Spectrum Analyzer (E4A02)Article
How a spectrum analyzer displays signal energy vs. frequency — essential for evaluating transmitter performance.
Two-tone Test (YouTube)Video
How a two-tone test evaluates SSB transmitter linearity and intermodulation distortion performance.
Oscilloscope Operation 1 (YouTube)Video
Getting started with an oscilloscope — controls, probes, triggering, and reading waveforms.
Oscilloscope Operation 2 (YouTube)Video
Advanced oscilloscope measurements — time/div, volts/div calibration, and making accurate measurements.
7.9
Avoiding Interference
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RF Grounding Conductors (T4A08)Article
Why RF grounding differs from electrical safety grounding and how to properly ground your HF station.
RF Interference Types (T7B03)Article
Categories of RFI — conducted, radiated, intermodulation, and harmonic interference — and how to identify each.
Ignition InterferenceArticle
Vehicle ignition noise in mobile ham installations and practical suppression techniques.
Part 15 DevicesArticle
FCC Part 15 unlicensed devices and how they can cause interference to amateur radio stations.
8
Safety
2 lessons — Electrical & antenna safety, RF exposure
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8.1
Electrical & Antenna Safety
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Tower Grounding (T0B08)Article
Proper tower and antenna grounding to protect your station from lightning and static discharge.
Electric Shock ProtectionArticle
How electrical shock occurs and the protective measures for amateur radio station safety.
RF Burns (T0C07)Article
How RF energy causes burns and injury — safe practices for working around transmitting antennas.
ARRL Safety PageExternal
ARRL's comprehensive safety resource — electrical safety, RF exposure, tower safety, and emergency procedures.
Grounding & Bonding Book (ARRL)External
ARRL's comprehensive reference on station grounding and bonding for RF performance and lightning protection.
Ward Silver Grounding Video (YouTube)Video
Ward Silver N0AX's detailed presentation on ham radio station grounding and bonding practices.
8.2
RF Exposure Safety
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RF Exposure Factors (T0C04)Article
The factors determining RF exposure levels — power, frequency, duty cycle, distance, and antenna gain.
RF Exposure Calculator (Hintlink/VP9KF)External
Online calculator for RF power density and MPE compliance evaluation for amateur radio stations.
ARRL RF Exposure CalculatorExternal
ARRL's online RF exposure calculator for evaluating amateur station compliance with FCC exposure limits.
RF Safety Information (ARRL)External
ARRL's complete RF radiation safety information — FCC rules, exposure limits, and evaluation guidance.