I respectfully have to disagree with Steve on this.
Stacking with a lower antenna is highly unlikely to produce a lower wave angle.
So a Full-sized 3L will still be almost always superior to a 2L at the same
height and that extra 1 – 2 db at the right angle at the right time with the
full-sized 3L antenna could be significant. What stacking might give you is a
higher (than the 3L) wave angle that is useful to some population area of
contesters that you will now be louder into. And it will give you potentially
three different wave angles to choose from if you phase them and have Upper,
Lower or Both switching. However, you will have a less broadband antenna with
reduced F/B and F/S which could handicap you when dealing with qrm and qrn.
And you will have to put that 2nd antenna very low to get meaningful wave angle
choices and those wave angles may not be very useful especially for working DX.
Every qth is different – with different topography, terrain and other factors
to take into consideration. Everyone should do extensive modeling with your
own specific terrain BEFORE seriously considering stacking a 2nd antenna to see
if it is even worth considering. And you also need to consider the additional
wind load on the tower and whether or not what you have up in the way of tower
and guys will support that additional “wind-sail”. :-)
73
Bob KQ2M
From: k7lxc--- via TowerTalk
Sent: Tuesday, March 13, 2018 12:54 PM
To: bmarx@bellsouth.ne ; towertalk@contesting.com
Subject: Re: [TowerTalk] add a 3rd el to 40-2cd
> With one antenna at 72 ft why not just add new antenna lower on the tower>?
One of my all time favorite ideas. Stacked would give you similar
performance to a full sized 3L plus you get angle and directional diversity.
And you don't need expensive rotators! Like my old buddy Mark, AA6DX sez:
"Worky, worky!"
Cheers,
Steve K7LXC
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