GROL study guide
GROL · Work through your exam, one topic at a time.
The General Radiotelephone Operator License (GROL) is a commercial operator license issued by the U.S. Federal Communications Commission. The GROL study guide has 9 sections and about 2,990 words.
01FCC Rules and Regulations: Licensing, Responsibilities, Allocations, and International Agreements
Nearly every maritime question traces back to Title 47 of the Code of Federal Regulations. Part 2 holds frequency allocations, station identification, and RF-exposure rules; Part 80 governs ship stations; Part 87 covers aviation; Parts 90 and 95 cover land mobile and personal radio; Part 97 is amateur.
324 words, about 2 min02Radio Operating Procedures: Distress, Urgency, and Safety Communications
Traffic priority descends: distress, urgency, safety, then routine. Distress uses MAYDAY, spoken three times, on VHF Channel 16 (156.800 MHz) or MF 2182 kHz.
302 words, about 2 min03Electronic Fundamentals: DC and AC Circuits, Components, and Semiconductors
Ohm's law (V = IR), power (P = VI = I squared R = V squared / R), and Kirchhoff's voltage and current laws underlie most items. Resistors in series add; in parallel the reciprocals add.
369 words, about 2 min04Practical Circuits: Power Supplies, Amplifiers, Oscillators, and Troubleshooting
The chain is transformer, rectifier, filter, regulator. A half-wave rectifier produces ripple at the line frequency and needs a large filter; full-wave and bridge rectifiers produce ripple at twice line frequency, which is easier to filter.
323 words, about 2 min05Signals, Emissions, and Modulation: Analysis and Emission Designators
A modulated signal consists of a carrier and sidebands. In amplitude modulation with modulation index m, total power = carrier power x (1 + m squared / 2); each sideband carries m squared / 4 of the carrier power.
350 words, about 2 min06Antennas, Transmission Lines, and Feed Lines
A half-wave dipole is about 0.5 wavelength in free space; end effects shorten a practical wire. Classic shortcuts: half-wave length in feet is about 468 divided by frequency in MHz; quarter-wave is about 234 divided by frequency in MHz.
327 words, about 2 min07Radio Wave Propagation
At MF and below, the ground wave follows the earth's curvature and carries 2182 kHz traffic for hundreds of miles. Above roughly 30 MHz, propagation is mostly line of sight plus slight diffraction: the radio horizon extends beyond the geometric one, roughly d(nm) = 1.23 x square root of h(ft) for one antenna.
350 words, about 2 min08Transmitters, Receivers, and Transceivers: Architecture, Performance, Interference Control
Most receivers mix the incoming signal with a local oscillator to reach a fixed intermediate frequency, where filters and gain are cheap and stable. Image response is the classic weakness: the image sits on the opposite side of the local oscillator, so with high-side injection the image frequency = signal + 2 x IF.
303 words, about 2 min09Microwave, Radar, and Ancillary Ship and Aircraft Radio Systems
Above roughly 1 GHz, lumped LC circuits give way to cavities, striplines, and waveguides. A waveguide is a high-pass structure: below cutoff frequency the wave will not propagate.
342 words, about 2 min