Artificially constrained designs can be some of the most difficult and interesting projects. The amateur radio world is no stranger to it, with homebrew radio designs that sort of put a line in the sand. Such designs are usually very minimalistic and educational about the first principles, which is one reason we like them so much.
A perfect example of this design philosophy can be found at [VK3YE]’s twist on the classic “10-minute transmitter”. (Video, embedded below.)
The design dates back to at least the 1980s when [G4RAW] set the challenge of conjuring up a functioning transmitter from garbage can parts and establishing contact within 15 minutes – ten for building and five for working on the belts. [VK3YE] used the “oner” design with a transistor for its 10 minute transmitter, but invested extra time adding a low pass filter to keep its signal clean and a power amplifier to boost the output a bit.
Despite the elaborations, the design is very simple and easy to understand. Construction is the standard “Ugly Style” This ham prefers such quick builds. There are no parts that are terribly difficult to find, and everything fits in a small metal box. The following video shows the design and setup as well as some experiments with WebSDR receivers to check the range both with and without the power amplifier.