Antennas, simulations, antennas related projects and information.

Horizontal Loop
at 3.5 MHz



We have a horizontal loop of 4 wires of 20m each at 15m high. 
This antenna will resonate normally at 3.82 MHz using F MHz = 306 / Lenght of loop in m.

The project looks like this:

CM Horizontal loop
CM also known as "Sky warmer"
CM very good for local at low heights
GND Reference
UNITS Meters
Height 15.000
Over Ground 13 5 (Diel. - Cond. mS)
Boundary Circular
F 3.500
GW 0 10 0.000 0.000 0.000 0.000 20.000 0.000 0.002
GW 1 10 0.000 20.000 0.000 20.000 20.000 0.000 0.002
GW 2 10 20.000 20.000 0.000 20.000 0.000 0.000 0.002
GW 3 10 20.000 0.000 0.000 0.000 0.000 0.000 0.002
S 1 5 100 0 
Coax 120

How do we plot gain patterns?

  • Open the Far Field pattern window using Plot > FarField.
  • We click first on ZEN to plot the Zenith or elevation pattern 
    Angle should be 0 which means we are plotting an elevation pattern in the direction of the 0 deg. Azimuth (horizontal)
  • We get a pattern with some lobes. The angles for the lobes are printed on the left side of the plot. By clicking on Angle with the LEFT mouse button we will load the best elevation angle in Angle. This means that any horizontal pattern we plot will be at this elevation.
  • Click with left mouse button on Angle
  • Click on Az to plot the horizontal pattern at the elevation displayed in Angle.
  • Click on Angle with the RIGHT mouse to load best Azimuth if not zero.
  • A click on Zen will now plot the BEST gain in horizontal and vertical.

Gain and Patterns for this loop

At 3.5MHz the gain is 7.85 dBi at 90 degrees which explains the "could warmer denomination". No need to plot horizontal pattern at 90 degrees.

At 7 MHz we have two lobes of 5.6dBi at 39 deg elevation. Note how horizontal pattern has four lobes at 90 degrees angles.

At 14MHz we have now three lobes but two are 7.05 dBi at 20 deg. The horizontal pattern plotted at an elevation of 20 degrees show multiple lobes in horizontal plane.

At 28 MHz we get a lot of lobes because we are too high from the ground

At 10 degrees elevation we have a butterfly pattern with max lobes at 23 deg azimuth (and 156, 204, 337 deg)

If we click with right mouse on angle to load 336 then plot a ZEN pattern we get the vertical pattern in the direction of the 337/154 lobes. We see that the lowest lobe is 11.17 dBi at 10 degrees elevation.

We can try to left click and plot a horizontal pattern at the 10 degrees elevation but will just get the pattern above which means that we found the maximum gain for that band.


If you have questions, comments, critics, suggestions:

This document is Copyright 2003 ORION Microsystems by Madjid BOUKRI