Those of us who work with electronics will usually come to the art through a particular avenue that we master while imbibing what we need from those around it. For example, an interest in audio circuitry may branch into DSP and microcontrollers as projects become more complex. Some realms though retain an aura of impossibility, a reputation as a Dark Art, and chief among them for many people is radio frequency (RF). Radio circuitry is often surprisingly simple, yet that simplicity conceals a wealth of complexity because the medium does not behave in the orderly manner of a relatively static analogue voltage or a set of low-frequency logic levels.
Chris Gammell is a familiar face to many Hackaday readers for his mastery of much electronic trickery, so it comes as something of a surprise to find that RF has been one of the gaps in his knowledge. In his talk at the Hackaday Superconference he took us through his journey into RF work, and the result is a must-watch for anyone with a curiosity about radio circuitry who didn’t know where to start.
For readers whose introduction to electronics came through the medium of amateur radio, the talk will follow a familiar path as it deals at a simple level with the very fundamentals of how signals pass through circuitry at RF frequencies. We learn about matching and gain, and most importantly about losses between stages and how careful design can minimise them. He makes the point that advances in integrated circuits have put wireless capabilities within the range of almost any designer, and it’s worth observing that this along with a more relaxed approach to spectrum usage in most regions means that ever-higher frequencies have become the norm at which physical design becomes ever more critical.
The talk continues with his discoveries in test equipment, in PCB layout, and in the shortcomings of common components at higher frequencies. It’s a subject that we’ve touched on before in a report from a previous Superconference, as RF design guru Michael Ossmann gave us his tips.
If you’re an experimenter this shouldn’t be an area to be afraid of. The low cost of so many of the devices and modules involved mean that there is plenty of scope to give it a try without breaking the bank. At a simpler level some experience can also be gained with more traditional RF, try experimenting with TV antenna pre-amplifiers for example, something for the 70cm amateur band, or even messing about with scrap UHF TV tuners. There may be plenty of pitfalls for the unwary RF experimenter, but there is still plenty of scope for learning experiences.