Dan Koellen AI6XG 

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    Evaluating efficiency, transformer and mismatch losses in toroid transformers - some observations.
    Dan Koellen AI6XG
    • Jun 17
    • 5 min

    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.
    20 views0 comments
    Reactive Component Measurement With the NanoVNA
    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.
    61 views0 comments
    Toroid Transformers - How Hot Will It Get?
    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...
    265 views0 comments
    Electrostatic Discharge (ESD), Does it Matter for Makers and Hackers?
    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...
    519 views0 comments
    Don't Fear the Smith Chart
    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...
    591 views0 comments
    Trapped 20/30/40 Meter EFHW Antenna
    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...
    5,381 views0 comments
    Big Font Clock Update:  Dimmer-Interface PCB and Setup Instructions.
    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,...
    144 views0 comments
    End Fed Half Wave Antennas: More About the Primary Capacitor
    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)...
    4,294 views1 comment
    End Fed Half Wave Antennas: Is a Primary Capacitor Really Needed?
    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....
    10,801 views3 comments
    Big Font Clock - Relieve for Old Eyes
    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...
    417 views0 comments

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    • HOME

    • Electronics

      • Making and Hacking
      • Vintage Electronics
    • Ham Radio

    • SOTA

      • Antennas
      • W6 Activations
      • W7 Activations
    • ABOUT ME

    • More

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