Mike,
With EZNEC+ v.5.0.59 I modeled a 40M ground plane:
Wire #1 starts at 0,0,10 (ft) and runs to 0,0,43 (33 ft long)
Wire #2 starts at 0,0,10 (ft) and runs to 0,33,7 about 33 long and slopes
down from 10' to 7'
Wire #3 starts at 0,0,10 (ft) and runs to 0,-33,7 about 33 long and slopes
down from 10' to 7'
On 7.1 MHz EZNEC shows a clean pattern with a deep overhead null and a 25
deg take-off angle (over Real/High Accuracy earth)
On 21.1 MHz EZNEC shows an ugly pattern with an overhead null and a 45 deg
take-off angle (over Real/High Accuracy earth)
Looks like the take-off angle is much higher on 15M than on 40M.
73,
Marsh, KA5M
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Mike
& Coreen Smith VE9AA
Sent: Sunday, May 26, 2013 6:23 AM
To: towertalk@contesting.com
Subject: [TowerTalk] 40m ground plane on 15m-pattern
Has anyone ever modeled a 40m ground plane?s pattern on 15m?
This weekend of very poor condx on 15m during CQWW WPX CW has given me extra
time to mull over what I am using on 15m.
Currently I am using a wire ground plane cut for the 40m band, base up about
10?. Antenna is wire, with 2 elevated radials, sloping down somewhat (15º
maybe). Directly fed with coax. SWR is FB on 40 and 15m. Hung off the top
of a Maple tree.
It works really well on 40m, but I am wondering if the pattern is distorted
or very elevated on 15m? (high angle?)
Reason I ask, is I was accidentally listening on my 160m(multiband) dipole
that is only up 10? last night and many station were the same strength ! ! !
There?s more to it than that, but the gist of my msg is I wish to know the
elevation plot of a 15m signal on a 40m ground plane please.
Cheers/TNX,
Mike VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
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