LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #11   Report Post  
Old April 7th 05, 01:41 AM
John Smith
 
Posts: n/a
Default

Cecil:

Here is the crux of my fruitless attempts to use EZNEC...
With EZNEC, when I plug in the value of my gamma rod and -jxr, along with
all other elements, EZNEC spits out an error! (something about too short a
loop seems to bother EZNEC, but this short loop IS working!)
However, I am looking at a REAL and functional antenna which appears to be
well matched and receiving well.
So, I end up throwing up my hands and just using the antenna and going about
with the "cut-and-try" method! (probably just my inability to use the app)

Regards,
John
--
I would like to point out, I do appreciate the "Been there--done that!"
posts. Indeed, now your observations, comments and discourse should be
filled with wisdom--I am listening!!!
"John Smith" wrote in message
...
Cecil:

One element I do not understand in EZNEC is: say I end up with 225 ohms
inductive reactance in the gamma rod(just an example figure, use any you
please), how do I inform EZNEC I am inserting a 225 ohm capactive
reactance,
at the feedpoint to offset it?
Or, I am all wet in considering this?

Regards,
John

--
I would like to point out, I do appreciate the "Been there--done that!"
posts. Indeed, now your observations, comments and discourse should be
filled with wisdom--I am listening!!!
"John Smith" wrote in message
...
Cecil:

Your work with EZNEC is greatly appreciated here.
Your configuration is for a horz ant and I am working with a
vertical--conversion is trivial.
"A picture is worth a thousand words..." has real significance here.
I am sure an analysis of your file will provide me with insight into the
workings of EZNEC and accelerate my learning curve!

THANKS!,
John

--
I would like to point out, I do appreciate the "Been there--done that!"
posts. Indeed, now your observations, comments and discourse should be
filled with wisdom--I am listening!!!
"Cecil Moore" wrote in message
...
Cecil Moore wrote:
John Smith wrote:
I cannot find a configuration on the gamma which brings the swr under
that figure...

As Richard H. said, find the point where the feedpoint
resistance is 50 + jXL ohms. That must occur somewhere.
Then tune out the reactance with a series capacitor.

I've used EZNEC to model a gamma-fed 33' 20m dipole at
40' made out of 0.5" aluminum tubing. With a gamma element
three feet long 6" below the 33' element and a series
Xc=122 ohms, it indicates a feedpoint impedance of
49+j0.3 ohms. The EZNEC file can be downloaded by
clicking on the link below.
--
73, Cecil http://www.qsl.net/w5dxp/GAM20DIP.EZ


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000
Newsgroups
---= East/West-Coast Server Farms - Total Privacy via Encryption =---







 
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
please need help with delta loop antenna better matching system than gamma match Silvio Antenna 4 November 15th 04 08:42 PM
Problem with Gamma Match? Jason Dugas Antenna 1 August 13th 04 03:22 AM
Gamma match question 6-meter yagi Shadow 998 Antenna 9 June 22nd 04 02:05 AM
Gamma Match g subs Antenna 2 March 20th 04 03:42 PM
Gamma match: Inherently inferior to balanced match systems? Cecil Moore Antenna 5 September 24th 03 04:57 PM


All times are GMT +1. The time now is 01:36 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