Dan Koellen AI6XG
Evaluating efficiency, transformer and mismatch losses in toroid transformers - some observations.
Two methods for transformer loss are evaluated. We learn that mismatch loss must be accounted for.
Dan Koellen AI6XG
- May 16
- 6 min
Reactive Component Measurement With the NanoVNA
Exploration of using the nanoVNA to measure inductance and capacitance at frequency of use.
295 views0 comments
Dan Koellen AI6XG
- Mar 2
- 11 min
Toroid 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...
740 views0 comments
Dan Koellen AI6XG
- Jul 20, 2021
- 9 min
Electrostatic 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...
573 views0 comments
Dan Koellen AI6XG
- Jun 16, 2021
- 13 min
Don't Fear the Smith Chart
Like many radio amateurs I was initially intimidated by the Smith chart. Transmission line and antenna theory, unfamiliar terms and...
792 views0 comments
Dan Koellen AI6XG
- Oct 4, 2020
- 8 min
Trapped 20/30/40 Meter EFHW Antenna
An End Fed Half Wave (EFHW) antenna for operation on 20, 30 and 40 meters was built for SOTA operation. By using traps, the antenna...
6,175 views0 comments
Dan Koellen AI6XG
- Jun 29, 2020
- 7 min
Big 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,...
154 views0 comments
Dan Koellen AI6XG
- Jun 6, 2020
- 4 min
End Fed Half Wave Antennas: More About the Primary Capacitor
I recently posted a blog claiming that a capacitor in the primary of the matching transformer is not needed for end fed half wave (EFHW)...
5,167 views1 comment
Dan Koellen AI6XG
- May 27, 2020
- 3 min
End 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....
12,408 views3 comments
Dan Koellen AI6XG
- Feb 9, 2020
- 9 min
Big Font Clock - Relieve for Old Eyes
Recently 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...
441 views0 comments