This page is intended for users that want to experiment with a yagi design but do notneed all the rhetoric contained on the main Yagi Design Page. This page assumes that you have already read the information on the Yagi Design Page and understand what each of the text boxes and selectors are for. This page minimizes all the clicking, scrolling, and popups but still uses all of the same equations as the main Yagi Design Page. Any changes to the input data is immediately rendered in the design data at the bottom of the page.

Any output in a red font is usually a warning that you are trying to do something that it outside the capabilities of the design program. That's OK, as the program isn't going to anything real wierd. However, in extreme cases, you might get odd outputs, like negative numbers or "NAN" listings. Just try not to stray too far from the program capabilities.

The main restriction is to keep the required Gain between 11.8 and 21.6 dBd, and the Boom Length between 2.2 and 39 Wavelengths. Other restrictions exist that are frequency dependent. They are listed in the input areas.

VHF/UHF Yagi Antenna Design Input

Use the following entry areas to define your antenna requirements. Specifying a Gain > 21.6 dBd or a Boom Length > 39 λ will limit the design to 21.6 dBd Gain and Boom Length to 39 λ. The page will operate below the lower limits, 11.8 dBd of gain and and 2.2 λ Boom Length, but the output data may not be accurate. Input dimensions can be mixed and matched as all input data is converted to λ before calculations are done.

Design Frequency, Gain/Boom Length, Reflector
Spacing, and Director Element Spacing
Design Frequency
Select Foward Gain or Boom Length
For 12.0 dBd Gain, the Estimated Boom
Length is 2.284 λ = 61.3" = 1556 mm.
The maximum number of director elements that will fit
on this boomlength is 9, for a Actual Gain of 12.3 dBd
.
Reflector Spacing
Director Element Spacing
Boom Type/Diameter/Correction
and Element Diameters
Boom Type (Mounting)
At this frequency, the Boom Diameter should be limited to 0.06 λ, which is 1.6" = 40.9 mm.
Boom Diameter
A Metalic Boom with Bonded Elements and with a
diameter of 1.25" = 31.7 mm = 0.0466 λ has a
calculated Boom Correction of 0.6768 .
Boom Correction 0.
Mouse-Over to change value.
Limitation: 0.01 λ ≥ Element Diameter ≤ 0.02 λ
0.03" ≥ Element Diameter ≤ 0.54"
0.7 mm ≥ Element Diameter ≤ 13.6 mm.
Driven Element Diameter
Parasitic Element Diameter(s)

VHF/UHF Yagi Antenna Design Output

The Design Information, lower left drawing, is based on your input data from the previous section. The Antenna Dimension, lower right drawing, is based on your design specifications. You can use the buttons, on the top right and left of the Antenna Dimension drawing, to change from US/Imperial (default) to Metric. The drawing windows below may change size, based on your design requirements.

Design Information
440 MHz, 11 Elements, 12.293 dBd Estimated Gain
35.5 Degrees Horizontal Beam Width
37.3 Degrees Vertical Beam Width
1.25" Diameter Metalic Boom, Bonded Elements.
Boom Correction of 0.6768 applied.
Electrical Boom Length of 67.5" (5' 7-9/16").
Allow for overhang when cutting boom to length.
Driven Element Diameter = 0.25" (0-1/4")
Parasitic Element Diameter = 0.25" (0-1/4")
Suggested Stacking Distance for 2 Yagis:
38.5" (3' 2-1/2") Horizontally
36.6" (3' 0-21/32") Vertically
Dimensional tolerance required = 0.08" (3/32")
Antenna Dimensions
Cumulative
Spacing
Element
Element
Length
Zero
REFL
13-7/8"
5-3/8"
D.E.
12-3/4"
7-3/8"
D1
12-5/16"
12-7/32"
D2
12-5/32"
17-31/32"
D3
12"
24-11/16"
D4
11-27/32"
32-3/16"
D5
11-23/32"
40-1/4"
D6
11-19/32"
48-11/16"
D7
11-1/2"
57-17/32"
D8
11-7/16"
66-25/32"
D9
11-11/32"