Ham Radio QSO Parties

Continuing our look at how to make the most of simple wire antennas I am using EZNEC to compare the performance of a wire dipole antenna in various configurations. The goal here continues to be a simple to deploy antenna usable on the road for VAQP Expedition. Our initial focus will be a 40 meter half-wave design. Then we will compare this with other possible antenna geometries and also investigate whether adding a wire on or near the ground beneath the antenna helps radiate more power skyward. The baseline configuration will look like this…

This is an inverted V with the apex over 26 feet high and the ends pulled to about 3 feet above ground resulting in each element at a 45 degree angle.

I used EZNEC+ with this EZNEC File.

The ground is set to ‘real’ and ‘high accuracy’ with the default conductivity.

The broadside elevation pattern for 7100kHz looks great for NVIS…

The simulation suggests the gain straight up is a modest 2.8dBi, but the 3dB half-power angles are very wide. For comparison, the elevation pattern inline with the antenna looks like…

The half power angles are less, but this is really quite good for NVIS. The NASCAR drive-on stand and WonderPole flag pole would be a perfect way to achieve this antenna. The antenna wires can be part of the guying system. This antenna should set up in minutes and perform almost as good as a home station.

Using the above baseline antenna we will compare it with the following possibilities…

• Same Inverted V with Apex at 50 feet
• Same 40 meter dipole level at 26 feet
• Same 40 meter dipole level at 10 feet
• Same 40 meter dipole at 10 feet with half-wave wire on the ground
• Same 40 meter dipole level at 6 feet
• Same 40 meter dipole at 6 feet with half-wave wire on the ground

At the end of this series of articles we will summarize the results and look for a clear winning topology.