Antenna 014: The G5RV
Author: Frederick R. Vobbe, W8HDU
November 28, 2008
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The G5RV is an excellent all HF band antenna. It works well on 3.5 to 30 MHz. It's a dipole, using #14 to #10 wire, fed with laddar line. Because it's a dipole there are some directional qualities to it.

Specifically the G5RV is a 102 foot dipole with a 31 foot feeder of 450 ohm transmission line. You will need 110 feet between two points to attach the ends. And the mid point also needs to be supported. The height above ground should be at least 35 feet or higher.

It's design allows the transmission line to radiate so it achieves resonance on all bands from 80 to 10 meters. The impedance at the end of the 450 ohm feed line is 50-60 ohms. So you can attach the 450 ohm line to an SO-239 connector. Alternately, you can feed the end of the transmission line from a tuner. Figure 1 shows how the antenna looks.

Let's look at how this antenna functions. If you wish to optomised the G5RV you can calculate the "flat top" (dipole) length, we use the formula: 1428 / F Mhz = Length in feet. And the formula of the matching is: 468 / F Mhz X velocity of the twin lead = Length in feet. But for the sake of discussion lets assume our 102 foot dipole.

Size of the G5RV Antenna
Figure 1 - Lengths of the G5RV

The image to the left is the vertical pattern. You're standing to the side of the antenna looking at where the bulk of the RF is going. The green line is the direction of the RF. In the 160 meter example, the RF is going straight up in the air. In the 30 meter example you see that the RF is taking off at a 40 degree angle, and when we get to 10 meters the signal lowers to an angle of just 13 degrees up, off the horizon.

The image to the right is the horizonal. You're flying over the antenna, looking down on the antenna. The antenna is stretching from left to right.

Vertical Pattern Horizontal Pattern
160 Meter Vertical Radiation 160 Horizontal Radiation
1.900 mHz Vertical 1.900 mHz Horizontal

80 Meter Vertical Pattern 80 Meter Horizontal Pattern
3.800 mHz Vertical 3.800 mHz Horizontal

60 Meter Vertical Pattern 60 Meter Horizontal Pattern
5.366 mHz Vertical 5.366 mHz Horizontal

40 Meter Vertical Pattern 40 Meter Horizontal Pattern
7.100 mHz Vertical 7.100 mHz Horizontal

30 Meter Vertical Pattern 30 Meter Horizontal Pattern
10.125 mHz Vertical 10.125 mHz Horizontal

20 Meter Vertical Pattern 20 Meter Horizonal Pattern
14.150 mHz Vertical 14.150 mHz Horizontal

17 Meter Vertical Pattern 17 Meter Horizontal Pattern
18.110 mHz Vertical 18.110 mHz Horizontal

15 Meter Vertical Pattern 15 Meters Horizontal Pattern
21.100 mHz Vertical 21.100 mHz Horizontal

12 Meter Vertical Pattern 12 Meter Horizontal Pattern
24.930 mHz Vertical 24.930 mHz Horizontal

10 Meter Vertical Pattern 10 Meter Horizontal Pattern
28.400 mHz Vertical 28.400 mHz Horizontal

As you can see, the antenna's radiation pattern varies from band to band. One should consider this when building this antenna.

Frederick R. Vobbe, W8HDU

G5RV Antenna

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