[TowerTalk] FW: Antenna Question...

[Jim Brown]

You're looking at the wrong parameters when changing the length of 
parasitic elements -- the primary effect on directivity and gain.  Yes, 
varying the length of the reflector changes the feedpoint Z, but it 
mainly affects gain and directivity.  Resonance and feedpoint Z should 
be adjusted by varying the length of the driven element and the matching 
section.

The YW program, included on the CDROM that comes with the ARRL Antenna 
Book, is quite useful in studying the effects of element length, element 
diameter, and element spacing on gain, pattern, feedpoint impedance, and 
the bandwidth of both the match and the pattern.

73, Jim K9YC

On 10/29/2017 11:05 PM, Matt wrote:
> Increasing the reflector width while keeping the driver constant will shift
> frequency response down.