LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #23   Report Post  
Old May 3rd 12, 06:54 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2011
Posts: 117
Default HF is Smokin


wrote in message
...
Jeff Liebermann wrote:


snip


FYI I spent an afternoon with EZNEC exploring fan dipoles.

What I found was the farther apart the wires, the less the interaction,
which is what one would expect from common sense.

From my limited runs it appears that somewhere around 20 degrees is about
where the minimum separation needs to be for practical length adjustments.

At angles less than that be prepared to spend a lot of time pruning.

It doesn't matter if the wires are separated vertically or horizontally
other than horizontal separatation means you need lots of support points.

If the bands are too close together, i.e. 20-17, 17-15, 12-10, you can


I had a 10-20 fan dipole laying on a roof for a while. Matched OK after a
bit of pruning but I abandoned it when I found both bands were better with
antennas that were clear of the roof.

I wonder something (and I suppose I'll have to try it, now) : Say I had a
20m horizontal dipole up at 30 feet, could I feed it through a coax that had
a Tee-connector located 22 feet up and simultaneously feed a 15m antenna
from that Tee-connector?

Just as they would be in parallel as a true fan dipole with a common feed
point, so also would they be in parallel -- just not sharing a common feed
point.

Normally I avoid Tee-connectors because they introduce the Evil Mismatch but
this time ...

I can see one problem already; some of the 15m energy that divides at the
Tee-connector would go up to the 20m antenna and be partially radiated and
partially reflected. Standing waves. The coax length would alter the
effect.

"Sal"


 
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
PING Smokin Billy Goat Gruff rod Shortwave 1 May 21st 10 07:29 AM
Smokin Billy...Smoke This! Krypsis[_2_] Shortwave 6 November 21st 09 06:23 AM
Dave Smokin` de Ganja Mon nurk_fred2000 Shortwave 6 August 9th 09 05:00 AM
Smokin' Jukebox On AMMR AM Music Radio Broadcasting 0 February 15th 05 04:19 AM
Smokin Jukebox on AMMR AM Music Radio Shortwave 0 February 13th 05 07:37 PM


All times are GMT +1. The time now is 12:17 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