Introduction |
This page presents a series of 3-Element HF antennas that are easily constructed, "easily matched and easily tuned". By "easily matched and easily tuned" it is meant that, these antennas can be constructed and tuned on the ground. When the antenna is finally placed at height, there will only be a small decrease in F/B ratio. But the decrease is small and not worth trying to tune at height.
Note: The feed impedance for these yagi designs is 18-20 Ω. This means that a matching device will be necessary for the driven element, if you want to use 50/75 Ω coax or 75/300/450 Ω Ladder Line. See the web page on 2 and 3 Element Yagi Matching.
3-Element Parasitic Beam For 6 or 10 Meters |
3-Element Parasitic Beam For 11, 15, or 20 Meters |
Power Gain = 7.5 - 8.0 dB F/B Ration = 20 dB Radiation Resistance = 22 Ohms |
Power Gain = 8.0 - 8.5 dB F/B Ration = 25 dB Radiation Resistance = 20 Ohms |
Driven Element Length 475/FMHz (ft) || 144.8/FMHz (m) Director Length 436/FMHz (ft) || 132.9/FMHz (m) Reflector Length 505/FMHz (ft) || 153.9/FMHz (m) Element Spacing 185/FMHz (ft) || 56.4/FMHz (m) |
Driven Element Length 473/FMHz (ft) || 144.2/FMHz (m) Director Length 445/FMHz (ft) || 135.6/FMHz (m) Reflector Length 501/FMHz (ft) || 152.7/FMHz (m) Element Spacing 140/FMHz (ft) || 42.7/FMHz (m) |
Bandwidth for 1.75:1 SWR 1250 KHz at 10 Meters 2100 KHz at 6 Meters |
Bandwidth for 1.75:1 SWR 450 KHz at 20 Meters 840 KHz at 15 Meters 1070 KHz at 11 Meters |
Diameter of Elements 10 Meters = 1-1/2" 6 Meters = 1" |
Diameter of Elements 20 Meters = 1-1/2" 15 Meters = 1" 11 Meters = 1" |
The antennas in the table are detailed below. For the most part, the text associated with each antenna is pretty generic. However, if there is anything specific about an antenna, it will be listed in the description