Dan Koellen AI6XG6 days ago6 minReactive Component Measurement With the NanoVNAExploration of using the nanoVNA to measure inductance and capacitance at frequency of use.
Dan Koellen AI6XGMar 211 minToroid Transformers - How Hot Will It Get?There are a number of factors in choosing a toroid for a RF transformer. While one may model electrical performance, calculate predicted...
Dan Koellen AI6XGJul 20, 20219 minElectrostatic Discharge (ESD), Does it Matter for Makers and Hackers?Electrostatic Discharge (ESD) is a subject that can inspire a lot of discussion, head shaking and some misunderstanding. ESD damaging...
Dan Koellen AI6XGJun 16, 202113 minDon't Fear the Smith ChartLike many radio amateurs I was initially intimidated by the Smith chart. Transmission line and antenna theory, unfamiliar terms and...
Dan Koellen AI6XGOct 4, 20208 minTrapped 20/30/40 Meter EFHW AntennaAn End Fed Half Wave (EFHW) antenna for operation on 20, 30 and 40 meters was built for SOTA operation. By using traps, the antenna...
Dan Koellen AI6XGJun 29, 20207 minBig Font Clock Update: Dimmer-Interface PCB and Setup Instructions.A prior post described the development and build of a clock to display time and date for UTC and Local. The clock characters are large,...
Dan Koellen AI6XGJun 6, 20204 minEnd Fed Half Wave Antennas: More About the Primary CapacitorI recently posted a blog claiming that a capacitor in the primary of the matching transformer is not needed for end fed half wave (EFHW)...
Dan Koellen AI6XGMay 27, 20203 minEnd Fed Half Wave Antennas: Is a Primary Capacitor Really Needed?In my research on End Fed Half Wave (EFHW) antennas I found that nearly all have a capacitor in the primary (rig) side of the transformer....
Dan Koellen AI6XGFeb 9, 20209 minBig Font Clock - Relieve for Old EyesRecently the Maker Space that I frequent received a number of 4 line 40 character (4 x 40) LCD displays. They asked me to figure out how...