According to EZNEC+ v5.0.65
20M dipole up 31' over Real/MININEC ground with copper wire losses:
6.44 dBi max gain at 30 deg; -4.77 dBi gain at 5 deg takeoff
20M dipole up 95' over Real/MININEC ground with copper wire losses:
7.32 dBi max gain at 10 deg; 4.19 dBi gain at 5 deg takeoff
3L 20M monoband Yagi up 31' over Real/MININEC ground with aluminum losses:
14.08 dBi max gain again at 30 deg; 3.64 dBi gain at 5 deg takeoff
With the dipole and the Yagi both at 31' up, both will have the max gain at
the same takeoff angle - in this case 30 deg. But the Yagi will have almost
9 dBi more gain at 5 deg.
73,
Marsh, KA5M
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of David
Gallatin via TowerTalk
Sent: Thursday, November 06, 2014 7:27 AM
To: TowerTalk@contesting.com
Subject: [TowerTalk] Take off angle of yagi vs a wire antenna at about 30'
Hello group and once again I thank everyone who helped with my previous post
about the concrete.
My set up: Mosley TA 33 JR tri-bander that will be at about 31 feet. The
question: I've been debating ways to get at 40-80 meters. I have a very
small lot so cant run the usual wire suspects and was thinking about making
a mag loop.
But I've also thought about an end fed Chameleon or 33' Ultimax at about 28
feet as I do have room to run one of those horizontal to a tree. These are
multi-banded antennas but I've never given considered using them on 20,15,10
of course.
But then a thought occurred to me. Might the take off angles of the wire
antenna be different enough as to be beneficial for transmitting on those
bands and hitting different spots of the globe that the Mosley is skipping
over?
73,
David, AA9G
ex W5DCG and KC9EEV
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