On 1/30/2023 1:48 PM, Lux, Jim wrote:
On 1/30/23 9:46 AM, Grant Saviers wrote:
I agree side mount + swing arm is a good option.
Although my 7 K0XG R65 rings have worked great minus one motor
failure, I would do side mounts for future (unlikely) towers.
The advantages of side mounts are lower cost & weight, using standard
rotators, and if desired with multiple beams on a long mast between
rotator and top support.
The side mount disadvantages are less rotation (but still can get
~250*), some offset load on the tower (use 6 guys or star brackets),
and easily fabricated or purchased unique parts, although you/PE need
a design.
I think the updated Orion 2800 is a better choice than the Yaesu for
very big beams.
I've been thinking about this, and I wonder if there were some "not too
complex" scheme with an extra hinge point on the arm that would get you
360 degrees. Not that I would build such a thing (would that I had room
for it) - but I was thinking if you had an arm that is the length of a
"face" of the tower, and some sort of offset crank linkage, you could
get 360 of rotation from 240 degrees (or less) of movement from the
primary arm. My mind's eye has this as like a "wrist" that reaches
around the tower. Yeah, you'd have the mass of the antenna as a
cantilever load, which would put a bending moment on the tower.
A swing arm where the rotor is mounted straight off a tower leg is good
for 300° easy. That's plenty as long as you have another antenna to
cover the dead zone.
-Steve K8LX
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