Hello...

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

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

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

Thanks,
-Bob-
N1GYL