From the sortwave radio audio archive, a collection of recordings of several spy numbers stations, russian, spanish, cuban audio recordings
The intention was to determine also very small SWR ratios with small power exactly. With this SWR meter, for example, the inputs of RF amplifiers with power < -20 dBm can be measured. In German
A software defined receiver located in Tuscany Italy with a Windom antenna convering HF bands
The Trainer is based on a simple modular built STEM/game platform, plus newly developed interactive software,it contains six training routines, easy to advance, and consists of various learning aids. You select them from a menu. Feedback for menu selection is given audibly and through an LED display and serial monitor.
How to build a Simplified Arduino CW Trainer, this is a version that does not need a keyboard.
A simple 3D Paddel CW Key made of plastic with a standard 3d printer
An attenuator is needed for example, to generate defined levels starting from a reference level. With this attenuator control a measuring instrument can be calibrated.