Two way radios, and particularly the little 5-watt Handheld Transceivers (also known as HTs or walkie-talkies) put their little bit of power in every direction. Yet we sometimes know exactly what direction we want to transmit and would prefer all the power go that way.
A century ago two Japanese scholars created an antenna design to do exactly that. We call the design by one of their names, Yagi, but it seems the other, Uda, was the real inventor. Such is history.
Following 100-years’-worth of radio technician footsteps, I have designed a simple hardware-store Yagi antenna to focus 147 MHz signals in a primary direction. I used some heavy copper grounding wire and a 4-foot piece of PVC pipe, costing under $10.
The dimensions are specific to 2-meter Ham radio, but could be adjusted for other frequencies. GMRS, for example would be about one third the size in every direction.
