Going to a 3" mast should improve the grip, however before I would do that I
would carefully look at the mast clamp. There has been a lot of posts about
the Orion clamps slipping and the bolts loosening. Perhaps the grip area is
too small or it doesn't properly fit your mast. I think if you are relying
on the mast slipping to save your rotator, your have a poor design. At my
previous station in Illinois I had 60 foot boom 20m antennas and a full size
40m antenna with a 90+ foot 80m dipole interlaced and I never had to climb
the tower to re-align anything after a wind storm. You could used the Green
Heron controller as W9GE suggested and re-align the antennas from inside the
shack, however your coax loop would no longer be adequate. The Yaesu
G-2800DXA I think is similar to the Orion 2800 however it uses and aluminum
mast clamp and the mast is pinned with an 8mm bolt. I'm not sure how the
Orion is constructed and it's possible that pinning the mast wouldn't damage
anything.
John KK9A
To: towertalkSubject:
Re: [TowerTalk] Orion Rotator
From: "Al Williams"
Date: Sat, 14 Oct 2006 08:42:14 -0700
It depends on what is meant by "failed". The Orion rotator is prone to
having the readout direction not agreeing to where the antenna is pointing.
This is caused by two reasons. One is that the current driving the rotator
motor may cross couple to the sense leads for the readout. The other reason
is that the mast may slip in the rotator/mast clamp. When I changed from a
separate pair of wires for the 200' readout sense lines to an rg58 coax that
seemed to cure the problem when I had the Cushcraft A4S beam installed.
When I changed the A4S to the MonstIR, the readout has become about 90
degrees offset from the antenna position.
I don't yet know if this was due to a return of cross coupling or the mast
clamp slipping. The weatherman says that the winds never got above 45mph
during that time. There have been a number of postings that describe that
several antennas being turned by the Orion and it seems to be ok. However,
as I mentioned in a previous posting, the inertial torque of a rotating the
MonstIR may cause the slipping. No one responded to that posting.
Also, another local had his MonstIR slip that k7lxc installed. k7lxc was in
the process of having a different mast clamp designed for the Orion. Some
pin the mast to the clamp but Orion voids the warranty if done and even
promotes the slipping as a good feature in that it protects the rotator!
I have been wondering if a 3 inch diameter mast would be held better by the
clamp. If so a short 3 inch mast section could be pinned to the 2 inch mast
that must be used to go through the top collar of my crankup. Any comments
from mechanical genius's?
k7puc
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