Antenna Model · Designer · closed-form
Quarter-Wave Vertical / Ground-Plane
length = factor × λ × k · λ = 41.93 m @ 7.150 MHz
FIG.1 · QUARTER-WAVE VERTICAL / GROUND-PLANE
Radiator
9.958m
Radials ×4
10.168m
Accuracy note
±~3%, trim to resonance; an elevated ground plane gets you close to the stated feed Z.
±~3%, trim to resonance; an elevated ground plane gets you close to the stated feed Z.
Method closed-form Cite ARRL Antenna Book Feed ~36 Ω over an elevated ground plane (rises toward 50 Ω well clear of earth).
- 4 elevated, resonant λ/4 radials form the missing half of the antenna.
- Shorten & load with the Loading Coil for a mobile whip.