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Topband: 160 delta used on 80

Subject: Topband: 160 delta used on 80
From: FWT <>
Date: Fri, 20 Aug 2010 10:39:13 +0200
List-post: <">>
Hi Bob, K6UJ,

I run EZNEC 5.0 for you:

Delta  ( equilateral) has 60 meters each side. ( thus apex is abt 56 
meters high, given your 4 meters base hight).
On 160M if standard fed for vertical - e.g. at about 20% off corner on 
any of its 2 side legs - you get indeed a deep null (-30 dB)
in vertical pattern and nearly 360° omni-directional horizontal almost 
(3dB skewed) circular pattern. As one  would expects.
Max gain is 4 dBi at 20° elevation on real ground of 0,005 Siemens/m and 
Dielectric:13 inthe model.
On 80 one gets also  a quasi omni-directional 360° circular pattern as 
well .
But ! on elevation diagramme, one gets a cloud-warmer if feed is kept 
same ( as 160M!
However if you like a deep null again in elevation, you have to move the 
feed to base wire-leg at abt 10% off corner -  I had to prune this so as 
to get a
current-node right in the middle of base wire , for a maximum null  of 
-20dBin my simulation.
What you get then is sort of a hat in profile -  with a dip in the 
middle of  -20dBi and its top border-ring showing
 max gain is in elevation is up  to 55° with 4 dBi and bottom ring at 
15° elevation with -0.6 dBi.

Hope this helps a little.

I can e-mail you off list the plots in  think in pdf files instead of 
Pierre, F3WT
UR RST IS ... ... ..9 QSB QSB - hw? BK

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