Log Periodic Dipole Array

Log Periodic Dipole Arrays, or LPDA is a directional antenna with relatively constant characteristics across it's wide frequency range. Before you start constructing your own LPDA using the LPDA calculator below, please read chapter 10 of the 20th Edition of the ARRL Antenna Book (Other editions of the ARRL Antenna Book work as well, but may have the LPDA described in another chapter.) The LPDA calculator below calculates an 13 element LPDA based on the design parameter τ, the lowest frequency you shall use, and the design parameter σ. You need to decide which values you want to use, and the LPDA calculator will do the rest of the math for you. You don't need to build an LPDA with all the 13 elements, if you for some reason wants to have a shorter boom length, or doesn't need a bandwidth that large, you just stop by the element that suits your preferences.

Design parametre τ:

Select a value between 0,80 and 0,98, usually between 0,88 and 0,95.

Lower design frequency (MHz):

Insert value

Design parametre optimal σ:

Calculated

Design parametre σ:

A value between 0,03 and 0,06 is usually used for HF.

Angle α:

Calculated

Lenght of shorting stub (m):

Calculated

Lenght of Element Ln (m):

Calculated

Lenght of Element Ln+1 (m):

Calculated

Lenght of Element Ln+2 (m):

Calculated

Lenght of Element Ln+3 (m):

Calculated

Lenght of Element Ln+4 (m):

Calculated

Lenght of Element Ln+5 (m):

Calculated

Lenght of Element Ln+6 (m):

Calculated

Lenght of Element Ln+7 (m):

Calculated

Lenght of Element Ln+8 (m):

Calculated

Lenght of Element Ln+9 (m):

Calculated

Lenght of Element Ln+10 (m):

Calculated

Lenght of Element Ln+11 (m):

Calculated

Lenght of Element Ln+12 (m):

Calculated

Distance Dn (m):

Calculated

Distance Dn+1 (m):

Calculated

Distance Dn+2 (m):

Calculated

Distance Dn+3 (m):

Calculated

Distance Dn+4 (m):

Calculated

Distance Dn+5 (m):

Calculated

Distance Dn+6 (m):

Calculated

Distance Dn+7 (m):

Calculated

Distance Dn+8 (m):

Calculated

Distance Dn+9 (m):

Calculated

Distance Dn+10 (m):

Calculated

Distance Dn+11 (m):

Calculated

Total lenght of array (m):

Calculated

Upper frequency limit (MHz):

Calculated

Upper frequency limit with Ln+11 as last element:

Total lenght with Ln+11 as last element:

Upper frequency limit with Ln+10 as last element:

Total lenght with Ln+10 as last element:

Upper frequency limit with Ln+9 as last element:

Total lenght with Ln+9 as last element:

Upper frequency limit with Ln+8 as last element:

Total lenght with Ln+8 as last element:

Upper frequency limit with Ln+7 as last element:

Total lenght with Ln+7 as last element:

Upper frequency limit with Ln+6 as last element:

Total lenght with Ln+6 as last element:

Upper frequency limit with Ln+5 as last element:

Total lenght with Ln+5 as last element:

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This page was last updated 21.12.14 .

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Log Periodic Dipole Array