By: KA5WNX
The Inverted V Beam Antenna
A Two Element Beam Design
Reflector Element
Driven Element
RF Direction
The two element inverted V, uses a parasitic reflector that is cut longer than the driven element and Resonates on a frequency lower than that of the driven element. It is approximately 5% longer than the driven element.
Since the driven element is calculated at 468/frequency, the reflector. should be about 5% greater. That would be 492/Frequency. Each of the legs of the driven element is 234/frequency.
The spacing between the reflector and the driven element can be anywhere from point .15 wavelength all the way up to point .25 wavelength. to reduce the antenna impedance.
A full wavelength is calculated at: 984/frequency in MHz .
Therefore, a .15 would be: 147.60 / Frequency
Therefore a .25 would be 246/ Frequency
Since the driven element is calculated at 468/frequency, the reflector. should be about 5% greater. That would be 492/Frequency. Each of the legs of the driven element is 234/frequency.
The spacing between the reflector and the driven element can be anywhere from point .15 wavelength all the way up to point .25 wavelength. to reduce the antenna impedance.
A full wavelength is calculated at: 984/frequency in MHz .
Therefore, a .15 would be: 147.60 / Frequency
Therefore a .25 would be 246/ Frequency
For the lower bands like 160 meters, 80 meters, 40 meters, and 30 meters, a .15 spacing is ideal. Higher bands, seemed to do better with a wider spacing of point .25 , however it is not much greater than one DB. By adding a reflector to your inverted V, you will realize a gain of approximately 3DB. In theory this should be double the gain. You will also notice that the back rejection is often better than 15 DB down.
Formulas are:
Reflector: 492/frequency in MHz .
Driven: 468/frequency in MHz .
Each leg of Driven: 234/frequency in MHz .
Spacing of .25 wavelength: 246/frequency in MHz .
Spacing of .15 wavelength: 147.6/frequency in MHz .
Reflector: 492/frequency in MHz .
Driven: 468/frequency in MHz .
Each leg of Driven: 234/frequency in MHz .
Spacing of .25 wavelength: 246/frequency in MHz .
Spacing of .15 wavelength: 147.6/frequency in MHz .
