LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #17   Report Post  
Old April 17th 08, 06:07 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Apr 2007
Posts: 23
Default Linear decoupling traps


On 16-Apr-2008, "Jim, K7JEB" wrote:

After a bit of e-mail correspondence and the
exchange of a single, crucial, 1000-word, picture,
I think we've bottomed-out on this. I'm seeing two,
distinct, dipole-like responses, one at 3.6 MHz
and one at 10.2 MHz.


I also played around with this yesterday on EZNEC. Started with a 75 M
center fed half wave at 30 feet high, added 20 M quarter wave stubs one
quarter wave (20 M) oout from the center. Got two low SWR points at ~3.5
MHz and ~14 MHz. By changing the distances to the stubs, the length of the
stubs, and the length beyond the stubs, I got the low SWR points to 3.9MHz
(2.8:1) and 14.2 MHz (1.2:1). Azimuth pattern on 14.2 MHz was sort of
omni-directional with major lobes at 45, 135, 225, and 315 degrees.
Pattern on 75 M was omnidirectional at high angles and max gain straight
up.

Conclusions: Might be useful as a way to add 20 Meters to a shortened 75 M
dipole. High SWR on 75 would still require a tuner. Losses were not
determined. More height might help.

Ken Fowler, KO6NO
 
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
Effectiveness of decoupling radials Owen Duffy Antenna 14 May 2nd 07 10:22 PM
Capacitor Traps [email protected] Shortwave 0 January 15th 06 07:47 PM
Decoupling coax transmission line Charlie Antenna 3 December 31st 04 04:27 PM
WTB : Beam Traps NA1VT Homebrew 0 October 16th 04 03:14 PM
WTB : Beam Traps NA1VT General 0 October 16th 04 03:14 PM


All times are GMT +1. The time now is 10:13 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