Dan Koellen AI6XG
All Wound Up About EFHW Transformer Winding
After successfully using an End Fed Half Wave (EFHW) antenna for SOTA, I decided to build a 10 to 80 meter EFHW antenna for my home...
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Dan Koellen AI6XG
Jun 17, 20226 min read
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.
1,526 views0 comments
Dan Koellen AI6XG
Mar 2, 202211 min read
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...
2,138 views0 comments
Dan Koellen AI6XG
Oct 4, 20208 min read
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...
10,111 views0 comments
Dan Koellen AI6XG
Jun 6, 20204 min read
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)...
8,920 views2 comments
Dan Koellen AI6XG
May 27, 20203 min read
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....
21,806 views4 comments
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