On Friday, 24 Jun 2005 16:58:38 -500, "Asimov"
wrote:

"Bob B." bravely wrote to "All" (24 Jun 05 11:01:20)
--- on the heady topic of "Attic antenna: rotator upside-down work?"

BB From: Bob B.
BB Xref: aeinews rec.radio.amateur.antenna:33120

BB Hello...

BB Will an antenna rotator like a Radio Shack or Channel Master work if
BB hung upside-down from a roof beam, or should I try to come up with a
BB way to secure it to the attic floor?

BB I know rotators are designed to handle a certain weight, but I can't
BB guess at what they'd do with a "negative" weight...

BB The antenna I'm looking to rotate is a Channel Master 8-bay bowtie.
BB (CM4228)

BB Thanks,
BB -Bob-
BB N1GYL


I think it might work because rotators are rated for a large wind load
and hanging upside down doesn't even seem to come close to that.
However, I'd call the mfr first to ask for their recommendation
before doing it. I doubt any gears in the rotator depend on gravity to
stay in place. OTOH do you think fix mounting the rotator shaft and
having the antenna hanging off the mast fixture instead might work?

A*s*i*m*o*v

... Thank Thor Friday Nears!

I don't think it would work. The reason is that the bearings that
must turn will likely only be located on the bottom section expecting
the antenna weight feeding down in that direction. Twisting left and
right is a different problem from hanging upside down. The top of the
rotor may not have the kind of thrust support for any bearing that may
be there.

I can't say for sure whether or not it will work without actually
looking at the specific rotor's construction, but I can easily imagine
that the engineers would not have included an upside down option as it
would add significant cost to hundreds of thousands of rotors only to
be used by a dozen or so....

Rather than speculate, I would suggest contacting the manufacture of
the specific rotor in mind.


--
73 for now
Buck
N4PGW