Paul
Perhaps less interesting, but simple, would be a sloping dipole/vertical dipole
fastened to the top of the tower. Unless you have a very short tower, this can
be an effective antenna on 30m. I have used them around the world and have been
quite satisfied.
You could also side-mount a single fixed element near the top of the tower.
Both of these ideas save a spot on your mast for some other antenna. When
operating in the USA with a single dipole element, there is not a lot of need
to rotate it. Now if you had a 3 element yagi, that would be different.
73,
Dale - N3BNA
From: N1BUG <paul@n1bug.com>
To: towertalk reflector <towertalk@contesting.com>
Sent: Sunday, July 15, 2018 9:06 PM
Subject: [TowerTalk] 40/30 antennas on same mast
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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