Calculators, Coaxial Cable Losses, Stacking Yagis, VSWR, Wavelength (λ)

Coaxial Cable Losses


Copyright © G4CQM 2020 Note: Losses shown in dB


Stacking Yagis by G4CQM


Conventional Yagi Four-Stack WAX8 seen in AOP


Conventional Yagi Four-Stack WAX8 seen above in AOP...

K6STI's Antenna Optimizer Professional (AOP) software makes easy work of yagi stacking when using Symbolic Dimensions. See WAX8 example, opens in new window... 4WX8.ANT.

With the Free Space Symmetric command only two sets of symbolic build representations are required for four yagis, one pair in mirror. Vertical and Horizontal stacking distances are easily changed making alterations and comparison very easy!

Meanwhile 4nec2 does not have the Free Space Symmetric option so some extra coding is required. However, Symbolic Dimensions can be used, so yet again altering spacing is very easy. See WAX8 example, opens in new window...

Several designers choose to use numerical file format where errors are difficult to spot and manipulation of design parameters is awkward and time consuming. Symbolic Dimensions make life much easier and more accurate requiring only one numeric value each to describe spacing, length and diameter!

All of my designs use DL6WU stacking distances throughout, however it is worth experimenting to finally obtain the lowest temperature...

I have observed that the -3dB Beam Width data/results produced by Arie Voors 4nec2 compared to K6STI's AOP can differ slightly, this could potentially result in less than optimal stacking distances, so keep this in mind!

Use this DL6WU based stacking calculator as a guide only for your yagis stacking distances, simply enter the -3dB Beam Width (Degrees) information found on each yagi design page...


Enter Freq (MHz):

Enter -3dB Beam Width (Degrees):




Resultant Stacking Distances:

E-Plane (Metres) =

H-Plane (Metres) =

E-Plane (Feet) =

H-Plane (Feet) =




Regard VSWR readings as a guide only particularly when trying to establish just how good your antenna is. Completely flat VSWR when measured at the station patch panel could for example indicate that the system may have hidden losses, be warned!


Consider that a VSWR of 1.5:1 equates to a Return Loss of 13.98dB OR a Mismatch Loss of only 0.177dB

Enter any one of the first three parameters below, then click SUBMIT to calculate % Reflected and Mismatch loss;


Please note that these VSWR calculators are intended for use in the context of VHF/UHF yagi antennas connected with 50-Ohms coaxial feeder cable.

Some authors quote Return Loss as a negative number, and this convention is still widely found in professional radio communication and telecommunications literature. However, caution is required when discussing increasing or decreasing Return Loss as these terms strictly have the opposite meaning when Return Loss is defined as a negative quantity.


Wavelength (λ)


A useful calculator to enable accurate cutting of coaxial cable stubs, in-line sections and more...

Vf, Ka etc   
f (MHz)   1 λ =  mm λ/2 =  mm λ/4 =  mm


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