Log Periodic Antenna Design
Type of Array
HF Array
VHF/UHF Array
Feed Line Parameters
Element Size
in Inches
Feeder Wire Size
in Inches
Frequency Range in MHz
Lowest
Highest
Design Parameters
Design Constant
Relative Spacing Constant
Optimum = 0.1434
Boom Length = 9 ft 6.986 in ... Number Elements = 4.9546
Element
#
Length / Resonant
Spacing
Length to
Diameter Ratio
[Element Size 0.5]
1
27 ft 2.910 in (18.060MHz)
653.821
2
21 ft 9.528 in (22.575MHz)
3 ft 3.229 in
523.056
3
17 ft 5.223 in (28.219MHz)
2 ft 7.384 in
418.445
4
13 ft 11.378 in (35.273MHz)
2 ft 1.106 in
334.756
5
11 ft 1.902 in (44.092MHz)
1 ft 8.086 in
267.805
Input Resistance:
Ro =
Operating Bandwidth:
B = 1.6445
cot Angle:
a = 1.2000
Bar
Bar = 1.4696
Characteristic Z of Feeder:
Zo = 490.4632
Bandwidth for Design Structure:
Bs = 2.4168
Bandwidth of Active Region:
Bar = 1.4696
Feeder Spacing:
S = 2.4178
Average Feeder Z:
Zav = 400.8311
Spacing Factor:
ang = 0.06708
Short out longest element
with a 6 inch stub
Total all spacing between all elements is 9.6504
Use the chart below to help determine a Design Constant and a Relative Spacing Constant