4NEC2 is free :-(
Several hundred segments, built in optimiser
Martin, HS0ZED
On 16/07/2018 17:50, N1BUG wrote:
Initially, nothing but 40/30 will be on the mast. At a later date I
plan to add some UHF yagis but the booms will be at right angles to
the 40/30. I expect little to no interaction with those.
I will try EZNEC but am limited to 20 segments. Perhaps 10 segments
per dipole will be enough for the case of two separate fed antennas.
If I could even begin to get a sense of future competency I wouldn't
mind buying software.
Paul
On 07/15/2018 11:43 PM, john@kk9a.com wrote:
I am not familiar with MMANA but this is quite easy to model using EZNEC.
There is no need to model your exact tubing diameters, certainly there must
be a dipole example that you can alter. I doubt that there will be much
interaction. What else is on the mast?
John KK9A
To: towertalk reflector <towertalk@contesting.com>
Subject: [TowerTalk] 40/30 antennas on same mast
From: N1BUG <paul@n1bug.com>
Date: Sun, 15 Jul 2018 21:06:11 -0400
I have been trying to model this (using MMANA) but I have a hard
time getting my head around modeling.
I have a full size 40 meter rotatable dipole which I plan to install
at 105 feet.
I want to put 30 meters on the same mast if possible. I had
considered two options but am not sure if there will be problems
with either or both.
Option 1 would be to add a 30 meter element to the existing 40 meter
rotatable dipole, making two parallel elements with one a few inches
above or below the other, common feed. I am not certain how well
this works on bands that are not widely separated in frequency.
Option 2 would be to put a full size 30 meter rotatable dipole
higher on the mast. The maximum achievable vertical separation would
be 10 feet with 40 meters at 105 feet and 30 meters at 115 feet. I
am not convinced this won't become a two element beam pointing
straight up!
Has anyone modeled these or similar configurations?
Thanks,
Paul N1BUG
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