View Single Post
  #30   Report Post  
Old October 23rd 08, 01:49 PM posted to rec.radio.amateur.antenna
Michael Coslo Michael Coslo is offline
external usenet poster
 
First recorded activity by RadioBanter: Jun 2006
Posts: 828
Default Antenna design question

Richard Harrison wrote:
Mike, N3LI wrote:
"Why would the velocity be less at increased (antenna element) width?"

Let B = the phase velocity on the antenna element, in radians per unit
length. 2pi/B = wavelength on the element.
Therefore, 2pi/B=velocity of phase propagation.
Due to the behavior of of open-circuited transmission lines and
open-circuited antennas:
B=2pif times sq.rt. of LC radians / unit length.

2 pi f / B = velocity of propagation.

It is intuitive that a fat antenna element has more L & C than a thin
element and thus a lower velocity of propagation.



I thought that the inductance tends downward as the diameter of the wire
increases. I can understand your calculation after the wavelength part,
but don't quite get the increased inductance part.


- 73 de Mike N3LI -