This page contains projects and electronic circuits that I have built. Some are amateur radio related, others not.
- 70MHz Quarter Wave Ground Plane – Building a simple 1/4 wave ground plane antenna for the 4m band.
- 144MHz Portable Yagi Beam – A compact, portable 6 element 144MHz Yagi antenna. built for quick assembly in the field or up mountains.
- Magnetic Loop Antennas – Experimenting with a VHF magnetic loop and a larger HF one in the back garden.
- Carolina Windom – Construction details for a 20m (66ft) off centre fed ‘Carolina Windom’ multiband antenna.
- 20m Loft Dipole – A crude shortened monoband dipole that fits in the average loft. My first HF antenna!
Baluns, UnUns and Impedance Matching
- End Fed Half Wave Antenna Coupler – Using a parallel tuned circuit to feed an end fed half wave antenna.
- 50 ohm 1:1 Balun – A simple 50Ω 1:1 voltage balun made from a ferrite core.
- 9:1 Magnetic Longwire Balun / Unun – A 9:1 impedance transformer for feeding end fed wires.
Capacitive Touch CW keys
- Simple CW Touch Key – Super simple CW touch key solutions
- Capacitive CW Touch Key – Purchase a capacitive touch key circuit board to build your own CW key!
- 144MHz Power Amp – A simple 144MHz power amplifier schematic.
- 472kHz transverter – A design by Roger G3XBM, providing around 10w on 630m band.
- Rig Interface – An isolated PC/transceiver interface for data modes.
Not radio related projects
- 12v > 240v Inverter – A simple inverter project using a PIC microchip, some MOSFET’s and an old transformer.
- Alkaline Battery Charger – A low constant current source for experimenting with recharging non-rechargeable batteries.