LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #9   Report Post  
Old December 7th 07, 04:21 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default Loading Coils; was : Vincent antenna

AI4QJ wrote:
I think I see why it no longer surprizes me after going through the smith
chart.
The 100 ohm line (10 degrees) is open. The 600 ohm line has a load impedance
of -j567 ohms, it is not open. The fact that it is terminated with an
impedance (the 100 ohm line) adds degrees on the chart. We should expect the
reactance of the 100 ohm line to add phase angle at the termination similar
to a "discreet component". Hope this makes sense; the smith chart makes it
very clear.


---43.4 deg 600 ohm line---+---10 deg 100 ohm line---open

The Smith Chart does make it clear what is happening.
Here is the math to go with it. The impedance at the
junction of the two lines is:

-j100*tan(90-10) = -j100*tan(80) = -j567 ohms
-j600*tan(43.4) = -j600*tan(43.4) = -j567 ohms

The phase shift at the junction of the two lines is:
80-43.4 = 36.6 degrees

Time permitting, I will work up the phasor diagrams of
the component voltages (or currents) at the junction
where rho = (600-100)/(600+100) = 0.7143
--
73, Cecil http://www.w5dxp.com
 
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
Single Wire Antenna {Longwire / Random Wire Antenna} - What To Use : Antenna Tuner? and/or Pre-Selector? RHF Shortwave 20 December 31st 05 09:41 PM
Single Wire Antenna {Longwire / Random Wire Antenna} - What To Use : Antenna Tuner? and/or Pre-Selector? David Shortwave 0 December 28th 05 05:24 AM
Single Wire Antenna {Longwire / Random Wire Antenna} - What To Use : Antenna Tuner? and/or Pre-Selector? David Shortwave 3 December 27th 05 09:59 PM
Single Wire Antenna {Longwire / Random Wire Antenna} - What To Use : Antenna Tuner? and/or Pre-Selector? David Shortwave 0 December 27th 05 09:18 PM
Vincent antenna Allen Windhorn Antenna 3 May 24th 05 12:37 AM


All times are GMT +1. The time now is 11:52 AM.

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