Antenna simulator for small vertical monopoles

This tool calculates the antenna capacitance and radiation resistance of small vertical monopoles at 475 kHz. It is by no means a replacement for antenna design software such as EZNEC, but should give a clue how the antenna will perform.
Following limitations apply:

  • Total dimension (H+L) less than 15% of the wavelength (= less than 95 m)
  • Wire or small tube construction (less than 2.5 cm)
  • The calculations assume an unobstructed antenna. Object near or under the antenna will reduce the radiation resistance and increase the antenna capacitance.

1. Select antenna type:


(single topload wire)

(single topload wire)

(multiple topload wires)

(multiple topload wires)

2. Antenna dimensions:

Antenna height (H, in m): Topload length (L, in m):
Number of topload wires: Topload wire spacing (S, in m):

3. Ground loss and environmental losses:

Very low loss (sea water or open area with many λ/4 radials)
Low loss (rich agricultural land, unobstructed antenna)
Average loss (pastoral land, almost unobstructed antenna)
High loss (forrested land, suburban location with obstructed antenna)
Very high loss (urban location, desert, very rocky ground)
Known ground / environmental loss: Ω (excluding loading coil loss)

4. Calculate: