The resonance of the Arctic King was made slightly high to enable accurate adjustments of system resonance to be made at the feedpoint.
A small choke was inserted in series with the elevated radials with the resulting SWR curve shown.
Resonance is adjusted completely separately from matching the resulting resistance (R) which is done with a 50 ohm to 12.5 ohm UNUN transformer.
The Radiation Resistance at resonance is 17.5 ohms (+/- 0.5ohms), which accounts for the slight SWR (1.4:1 at feed point) at resonance.
Modelling gives approximately 75% radiating efficiency and less than 1dB in ground losses.
