LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #10   Report Post  
Old October 16th 03, 06:24 PM
Cecil Moore
 
Posts: n/a
Default

Tom Bruhns wrote:
If you measure the voltage drop along the wire, it's essentially zero,
so along the wire the voltage between the end points of the dipole is
essentially the same as the voltage across the feedpoint.


Brain fart? The feedpoint impedance is the ratio of voltage to current.
The feedpoint impedance of a halfwave centerfed is low, around 70 ohms.
The feedpoint impedance of a halfwave endfed is high, thousands of ohms.

The voltage at the middle of a dipole is low and the current is high.
The same holds true for a 1/4WL monopole feedpoint fed against ground.

The voltage at the ends of a 1/2WL monopole is high and the current
is low. The same is true for the open end of a 1/4WL monopole.

The sum of the forward wave and reflected wave causes standing waves
on an antenna like the above. The voltages, currents, and impedances
vary somewhat akin to an SWR circle on a Smith Chart.
--
73, Cecil, W5DXP



 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pls comment on this dipole Steve Antenna 6 October 15th 03 12:08 AM
shortened dipole loaded Jerry Antenna 11 October 2nd 03 12:57 AM
10m dipole and tuner G. Doughty Antenna 11 September 25th 03 03:05 AM
Comet VA30 (base loaded tri-band dipole 40/15/10) PA3HHO Antenna 2 September 1st 03 07:33 PM
Dipole connected to grounded receiver? Tom Antenna 4 July 22nd 03 11:19 PM


All times are GMT +1. The time now is 01:11 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017