I am not sure where you are building this station. I have no experience with
swing arms however my P40A station had two Yaesu G-2800DXA rotators to turn
masts with 4el monobanders. Aruba is very windy most of the time and the
rotators held up perfectly without failure for a number of years. I used the
stock controllers which are easy to operate however a Green Heron controller
also works well with Yaesu and with that control you could set stops. The
only negative comment I have is that the hardware quickly corroded and in a
corrosive environment stainless steel would be a poor choice with an
aluminum rotator. I used a Skyhawk in early March while visiting Aruba and
it appears to be a nice antenna.
John KK9A - P40A
From: Bill K4XS
Doing the necessary planning and work in the US before I set up a station
outside the US and I've finished five side-mounted swing arm assemblies for
my
Rohn 55. The design of the swing arms is what I've used in the past..."Z"
shaped, about 2 feet high and about 33 inches wide made of 1.5 inch "L'
angled
aluminum. The rotor shelf and the thrust bearing shelf are also constructed
from the same material and are constructed in the typical "criss-cross"
pattern to create the shelf. The criss-cross distributes the load across
all
the legs of the tower. The swing arms will of course cover around 300
degrees.
The station will employ 3 stacked tribanders, all will be side mounted on
swing
arms and will be placed just above the three guy points of the tower. Two
will
have a second WARC duobander above them about 10 feet higher. The
duobanders
are Cushcraft A-3WS eachwith around a 3.5 sq ft windload. Due to clearance
issues, most commercial tribanders can not be mounted on swing arms and
clear
the tower. The three antennas under consideration are the KT34 (16ft boom
and
around 4.5 windload), KT36 (32 ft boom and 9.5 windload), and the Skyhawk
(24
ft boom, 8.5 windload).
Here's my thoughts on the rotors and choice of antennas. I'm planning to go
with Yaesu 2800s for all three rotors. On paper the KT36 and a Cushcraft
would be no issue, but it is a side mount and of course there is
considerably
more torque of the rotor...and the tower. The slightly smaller Skyhawk
again
coupled with the Cushcraft on paper looks good until you consider it is side
mounted...same issue. The even smaller KT34 obviously is even less of an
issue.
I don't want to undersize the antenna, but on the other hand I don't want to
tear up the rotor and/or the tower.
The safe bet would be the KT34 by M2. My previous experience with swing
arms
leads me to think I would be just fine with forces on the tower and rotor.
I'm
not sure of the Skyhawk and my gut feeling is I'd be asking for trouble
using
the KT36 with a longer boom (lots of torque) and the 9.5 windload.
So, bottom line, I need some feedback before i commit big bucks to antennas
and
rotors. What do you all think?
73 Bill K4XS/KH7XS
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