For the December video conference meeting, our vice-president Wes (N8QM), doesn’t want to schedule any of his stellar speakers since most of our members will be busy with Christmas and playing hooky from the meeting. Wes had been thinking of presenting the physics of harmonics but decided members would benefit more from condensed versions of two earlier presentations but with a theme of building a tuning stub. It is Wes’ sincere belief that all amateur radio operators should know how to build a tuning stub. But only if they don’t mind cutting coax to precision lengths and attaching PL-259s.
It will also be helpful to know a little basic electronics such as… a battery has a plus and minus. But in fact, the electronics knowledge required for the amateur technician’s license is very much more than sufficient.
We will review the ABCs of Smith Charts, then proceed step-by-step in a learning exercise. Using a nanoVNA, the vector impedance of a real life OCF dipole antenna will be measured at 15 meters (21.3 MHz) where the SWR will be read by the nanoVNA to be 4:1. We will then download the free computer app called SimSmith, install it as part of the presentation, and use it to design a turning stub. Wes would build the tuning stub step-by-step in the video conference cutting two pieces of coax and attaching PL-259s but will instead have it pre-built. He will plug it in to the nanoVNA and the new SWR will be found to be 1:1, not 1:1.3 or 1:1.2. He might even then plug the antenna into the HF rig and call out some CQ!
The public is invited to attend.