[TowerTalk] Rotor Selection Advice Wanted - Heavy Duty

[JCMonty]

Hello Tower Talkers:

I have a Steppir Monstir antenna (Love it by the way).

It has a Wind Surface Area of 23.9 square feet.

I am currently using a hy-gain TailTwister rotor (rated at 20 square feet).

I would like to replace the TailTwister rotor with one that has ample design
margin.

The rotor will be mounted in a US Towers 589 or 689 as soon as I can
purchase a used one (any leads on this would also be appreciated!).

73,

Bill Erickson

N6MXU


Dear Bill,

I have a Monst-IR as well, sitting on a Yaesu G-2800DXA.  It has never given
me any problem since it was installed.  We do not usually have high winds in
Memphis, TN; but we did have some >40MPH gusts during a fall storm this past
year and I suffered no resultant misalignment or dysfunction.  I used 2
DX-Engineering sintered clamps on the Monst-IR mast plate to mast
attachment, and the mast is pinned to the rotor.

If you search the archives you will find some disagreement regarding pinning
the mast to the rotor.  There is no doubt that a sufficient snap torque will
provoke catastrophic rotor failure.

You will also find some interesting commentary regarding mounting of what
are essentially rubber grommet type sound isolation couplings on the bottom
of the rotor to allow it to twist some on the base plate during high winds,
distributing some of the torque off of the clutch assembly.  I have not done
this, but consider it an intelligent precaution.

Further, there is a gentleman who has designed a latching mechanism for the
antenna plate which can be released to allow the antenna to swing during
severe stresses.  I never fully studied how it was done, or how many axis of
rotation were made free; but it has been copied, and modified, and discussed
extensively on the forum as well.

Best of luck in your search.

Jim Montgomery
AG4KM