LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #11   Report Post  
Old March 17th 09, 02:18 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default colinear representation in NEC

Owen Duffy wrote:
Thinking some more about it, my current thinking is that my analysis was
flawed. I was using the standing wave currents, when I should be using
the travelling wave components.


That's exactly the flaw committed by w8ji and w7el when
they tried to measure the delay through a 75m loading
coil using standing wave current which doesn't appreciably
change phase through a loading coil or through the entire
90 degree length of a monopole. Using standing wave
current, w8ji measured a 3 nS delay through a 10 inch
long coil, a VF of 0.27.

http://www.w8ji.com/inductor_current_time_delay.htm

W7EL reported: "I found that the difference in current
between input and output of the inductor was 3.1% in
magnitude and with *no measurable phase shift*, despite
the short antenna... The result from the second test was
a current difference of 5.4%, again with *no measurable
phase shift*."

Of course, phase shift is not measurable when one is
using standing wave current with its almost unchanging
phase. EZNEC supports that assertion. Bench measurements
support that assertion.

When traveling waves are used to measure the delay through
a 75m loading coil, the correct delay through w8ji's 10
inch coil turns out to be about 26 nS (~37 degrees) at 4 MHz
with a more believable VF of 0.033.

http://www.w5dxp.com/current2.htm
--
73, Cecil http://www.w5dxp.com
"Government 'help' to business is just as disastrous as
government persecution..." Ayn Rand
 
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
Vertical colinear Dave VanHorn Antenna 8 October 2nd 05 11:51 PM
representation of crime in the uk media smasha Broadcasting 0 September 8th 04 08:01 PM
"Diamond CoLinear"? Airy R. Bean Antenna 7 August 9th 04 10:22 PM
Colinear vhf/uhf from QST Mogens Antenna 0 October 1st 03 02:44 PM
vertical colinear Dave VanHorn Antenna 6 September 8th 03 07:18 PM


All times are GMT +1. The time now is 09:44 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