Building an HF and VHF radio
General receiver, transmitter, amplifier, filter and power-supply architectures.
Open project →Amateur radio workshop
Radio construction projects
This section gathers practical radio construction projects. Each project includes an architecture, educational schematic, bill of materials, adjustment method and test procedures.
Every transmitter or amplifier must first be tested into a 50-ohm dummy load. A wattmeter alone cannot detect harmonics or parasitic oscillations.
Where should you start?
1. NanoVNA
Comprendre les mesures RF.
2. Charge fictive
Disposer d’une charge 50 Ω fiable.
3. Récepteur HF
Construire sans produire de puissance RF.
4. Émetteur et amplificateur
Passer progressivement à l’émission.
General principles
Receivers
40-metre HF receiver
Direct-conversion receiver using an NE612, Si5351 and audio chain.
Open project →144 MHz VHF FM receiver
Superheterodyne receiver with preselector, 10.7 MHz IF and FM demodulation.
Open project →Transmitters
40-metre QRP CW transmitter
One-to-three-watt CW transmitter with buffer, driver, class-C final and low-pass filter.
Open project →144 MHz VHF FM radio
Low-power FM transceiver using a DRA818V module and UART control.
Open project →Amplifiers
HF QRP amplifier
Five-to-ten-watt push-pull class-AB amplifier with bias and thermal calculations.
Open project →Measurement and protection
Dummy load and RF wattmeter
Fifty-ohm load, resistor network, RF detector and wattmeter calibration.
Open project →Directional coupler and SWR meter
Forward and reflected power measurement, SWR calculation and automatic protection.
Open project →Using a NanoVNA
Calibration, S11 and S21 measurements, antennas, filters, cables and transformers.
Open project →