Input the data

Input data
Design frequency	Number of turns	Length of one turn (in wavelengths)
MHz
Bending radius	Conductor diameter	Width/height ratio
r=mm	d=mm	d=

The results

Results
Wavelength	Compensated wavelength	Bending correction
mm	mm	mm

Larger loop Total length Vertical separator Horizontal separatorl mm mm D1= mm Total compensated length Compensated vertical separation Compensated horiz. separation mm H1= mm Dc1= mm Antenna height Internal diameter H1=mm Di1=mm

Smaller loop Total length Vertical tube Horizontal separator mm mm D2=mm Compensated total length Compensated vertical tube Compensated horiz. separator mm mm Dc2=mm Antenna height Internal diameter H2=mm Di2=mm

Legend

This calculator generates a lot of data! Take care in the use of the information in order not to make mistakes...

Here's a little explanation:

Design frequency

Evident?

Number of turns

What's the twist of the antenna? (normally 0.5 or 1 turns)

Length of one turn

A few variations of the antenna exist. Normally the circumference (length of the loop) is 1 wavelength, but 1.5 wavelength and 2 wavelength versions exist (and work).

Bending diameter

As it's impossible to bend the corner abruptly at 90 degrees, this value is needed for the calculations. It's measure from the bending center to the center of the tube.

Conductor diameter

External diameter of the tube or coax cable.

Diameter/height ratio

Most frequently this ratio is 0.44, but slightly lower values (0.3 to 0.4) give better horizon coverage.

Compensated wavelength

Wavelength, compensated according to the conductor diameter.

Bending correction

Correction value needed according to the bending diameter.

Compensated total length

Total length of the loop, compensated for the bending effect, and the fact that the loop must be slightly larger (or smaller).

Compensated vertical conductor

Length of the vertical conductor (without the 'bends').

Compensated horizontal separation

This is in fact the horizontal part without the 'bends', and corresponds to the horizontal pipe necessary to support the cable.

Antenna height

Height of the loop (twisted!).

Internal diameter

The diameter of the (imaginary) cylinder on which the loop would be wound.

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(c) John Coppens ON6JC/LW3HAZ

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