Designing a radio with a single type of transistor

What do you do once you are already a skilled radio designer and restorer? Well, if you are Greg Charvat, you decide to build a shortwave radio using a single type of transistor as an active element. Normally, one would use number of different transistors, each designed to handle different amounts of power and amplifying bandwidth. Limiting yourself to a single type may seem like a mental exercise today (pun intended), but was apparently much more common back when transistors weren’t easy to come by, so Greg isn’t completely off his rocker. Also, by only using one kind of part, it should make repairs much easier.

Designing a radio like this is a little bit complicated, but not nearly as much as it might sound. The trick is to divide the radio function into manageable pieces, which can then be designed and tested individually. You will notice that Greg’s radio (pictured above) is made up of a bunch of small prototyping boards. Each board contains a single circuit with a specific function, and physically separating them makes it much easier to test the parts, as well as swap out the ones that might be malfunctioning. It’s also a neat design aesthetic, because it very closely resembles the way you would draw an electrical schematic to represent the circuit.

If you are interested in building a radio, I would strongly recommend giving it a go. Start with a kit, though, and pick one that explains the design of each stage so that you can learn how it works. It will definitely be an interesting experience, and who knows, it could be the start of a new passion! If you have a favorite kit or other guide to recommend, chime in on the comments.