2 replies to this topic

[Gary Evans]

The best reported results with a ½ wave monopole antenna have been using a vertical antenna with a 45 degree downward facing counterpoise. My application won't allow this and the counterpoise needs to be at 90 degrees to the antenna which will be mounted vertically. My question is from an engineering standpoint does the counterpoise need to be straight and do other electronics/wires near it have any affect on the antenna performance or is this just a try it to find out situation?

[Mr.RC-Cam]

The position of any counterpoise, ground, or nearby object, affects the antenna's beam pattern and resonance. The best way to see the effects is to use a software based antenna design application and play what-if's with it.

A 1/2 wave monopole is also called a End Fed Dipole and End Fed Half Wave. I think that if you Google those terms you will see that a half wave monopole may not be the ideal choice unless you add a impedance matching network to it. Yes, I know, many wireless video systems include a half-wave monopole whip, but these are provided because of their very low cost (with little regard to performance).

BTW, if you don't do anything to address the high impedance of the monopole then I don't expect that the position of the ground plane will have a huge effect on overall performance. So, the position you choose may not matter much. Just try it out and see how it goes.

[Gary Evans]

Thanks for the info!