LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #4   Report Post  
Old July 22nd 11, 07:35 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Cut length on antenna made from coax cable

On Fri, 22 Jul 2011 09:51:18 -0700, Jeff Liebermann
wrote:

if I should include the 0.67
velocity factor of the coax dielectric covering the center conductor.
Is it 19.2" or 12.9" for the driven element?


Hi Jeff,

Ah! The sleeve dipole re-emerges.

The exposed wire isn't much different from any other insulated wire
antenna. Air dominates the dielectric constant to the now remote
braid and the plastic ever so slightly shifts things. EZNEC includes
modeling insulated wire.

More's the issue of the dielectric coefficient of the braid pulled
back over the outer jacket of your coax. Coupling issues to the
insulated braid there too shift dynamics - and probably dominates the
DC characteristic.

I usually cut long, and slowly snip the exposed wire until SWR
improves. Choking the line would stabilize this.

73's
Richard Clark, KB7QHC
 
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
Building a Ready-Made "GreerTech" Coax Cable [Shielded] Loop Antenna with Multi-Heads RHF Shortwave 4 July 25th 07 03:29 AM
Cutting cable length to match 1/4 wave 162 MHz antenna? Robert Haston Antenna 6 July 25th 06 08:48 PM
TX to Antenna cable length? MRW Antenna 7 May 13th 06 02:55 AM
FS:RG8X 18 FT LENGTH COAX WITH COAX CONNECTOR Kb9igg Swap 0 October 31st 03 04:54 PM
TV antenna question-cable length Henry B. Antenna 2 July 22nd 03 03:10 AM


All times are GMT +1. The time now is 06:04 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