HB3YAQLucerne
LEARN · LIBRARY
Understand radio.
Reception, antennas and digital radio: find an explanation or start a guided learning path.
YOUR REFERENCE LIBRARY
25 / 25All learning articles
Start with 6 of 25. Choose a topic or open the full directory.
SDR & reception
Your first reception in a browser
From choosing a web receiver to hearing a clear signal: frequency, mode, filter and audio, step by step.
2 min read
Digital radio
Digital radio: from microphone to network
Understand codec, RF link, repeater and hotspot before programming a radio.
2 min read
Antennas & feed lines
Frequency and wavelength
From megahertz to metres, and why a calculated wavelength is not yet a finished antenna.
2 min read
Signals & measurement
Interpreting SWR correctly
What standing-wave ratio tells you about reflection, and which antenna properties it leaves unanswered.
2 min read
Propagation & navigation
Maidenhead locator, distance and direction
What JN47db describes, how precise a locator is and what direction a great-circle calculator gives.
2 min read
Station practice
Volts, amperes, ohms and watts
Calculate a DC load and distinguish electrical input power from RF output power.
2 min read
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SDR & reception
Reading the waterfall
Separate frequency, time and colour, and make useful observations from a spectrum display.
2 min read
SDR & reception
Understanding AM, FM and SSB
How speech travels on an RF signal and why mode, tuning and filters must match.
2 min read
SDR & reception
Gain, AGC and overload
Why maximum gain does not mean best reception, and how to check a receiving chain systematically.
2 min read
SDR & reception
Frequency error and SDR calibration
Translate ppm to hertz, assess a reference and distinguish frequency error from other drift.
2 min read
SDR & reception
Noise, bandwidth and sensitivity
Calculate thermal noise and understand when a narrower filter helps.
2 min read
Digital radio
D-STAR: callsigns and connection paths
Understand DV, repeaters, routing and reflectors, and check settings as a complete path.
2 min read
Digital radio
DMR: timeslot, colour code and talkgroup
Understand the main codeplug building blocks and assemble a channel without guesswork.
2 min read
Antennas & feed lines
Planning a half-wave dipole
Two arms, one feed point and several influences: from starting dimensions to useful tuning.
3 min read
Antennas & feed lines
Quarter wave, radials and counterpoise
Why a single rod is not the whole antenna, and how the RF current’s return path matters.
2 min read
Antennas & feed lines
Coaxial cable: loss and electrical length
50 Ω, attenuation and velocity factor describe different properties of a feed line.
2 min read
Antennas & feed lines
Impedance and matching
Understand resistance, reactance and reference planes using a calculable quarter-wave transformer.
2 min read
Antennas & feed lines
Antenna gain, dBi and EIRP
Gain describes direction and a reference, not an additional energy source.
2 min read
Signals & measurement
dB, dBm and power
Add ratios, read absolute levels and avoid the common factor-of-10 versus factor-of-20 mistake.
2 min read
Signals & measurement
Inductors, capacitors and resonance
Calculate reactance and understand why an ideal resonance alone does not describe a real filter.
2 min read
Propagation & navigation
Antenna height and radio horizon
Estimate Earth curvature, understand the k-factor and recognise terrain limitations.
2 min read
Propagation & navigation
Fresnel zones: more than line of sight
Calculate space around the direct path and assess obstacles at the correct location.
2 min read
Propagation & navigation
Building a radio link budget
Combine transmit level, antennas, losses and receiver threshold with explicit model limits.
2 min read
Station practice
Estimating battery runtime realistically
Combine transmit duty cycle, receive current and usable capacity in a transparent runtime model.
2 min read
Station practice
Voltage drop in supply wiring
Account for both conductors, cross-section and temperature, then assess voltage at the radio.
2 min read
UNDERSTAND · EXPERIMENT · PROGRESS
Go straight to all articles ↑Where would you like to start?
01LENGTH & FREQUENCY
Understand antennas.
Why does a frequency need a suitable antenna? Understand the dipole and calculate its starting length.
Explore the learning path6 steps · with knowledge checksCalculate a dipole02SDR · SIGNAL MODEL
Read signals.
What does a waterfall tell you? Learn about tuning, modes and filters, then try them in the simulated SDR lab.
Explore the learning path6 steps · with knowledge checksOpen the SDR lab03RADIO & NETWORK
Connect digitally.
From a channel to a repeater or hotspot: understand the connection and set up DMR or D-STAR step by step.
Explore the learning path6 steps · with knowledge checksEquipment guidesPrefer to read independently? Articles by topic
INDEPENDENT READING
Articles that build on each other.
These reading lists group the fundamentals by topic. The guided courses above also provide exercises and saved progress.
01
Hear your first clear signal
Open a receiver, read the waterfall and tune correctly.
02
Understand your antenna
From wavelength through the feed line to matching.
03
Set up digital radio
Understand the connection path, then explore D-STAR and DMR.
04
Plan a station
Calculate supply requirements, battery runtime and a radio link.