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
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
UR RST IS ... ... ..9 QSB QSB - hw? BK