View Single Post
  #4   Report Post  
Old July 18th 06, 08:34 PM posted to rec.radio.amateur.antenna
David David is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 37
Default Quarterwave vertical with radials

The vertical element is connected to the centre conductor (RF live). The
radials are connected to 0V on the transceiver.

If only the vertical is connected, the antenna still radiates although not
as well. If only the
radials are connected, the antenna does not radiate because the radials are
connected to 0V and not a varying voltage.

With both vertical and radials connected, the vertical element radiates the
wave. The wave is reflected by the radials as boundary condition of
Maxwell's equations. The reflection induces a current in the radials. This
current has a standing wave on it.

Do you think the above is correct? All parts of the antenna form the
impedance. Without radials, the impedance is poor and the vertical element
does not radiate well.

Other explanations say that displacement currents go through the air and
terminate on the radials. The displacement currents then becomes conduction
current in the radials. Displacement current is another anomaly with
electromagnetic theory.

I notice that two people have simulated the vertical antenna with radials
using EZNEC, and obtained different results. One simulation shows that the
radials radiate, the other shows that they do not.