[TowerTalk] Fw: Re: Removing a Rotator

[Roger (K8RI)]

ac9s at mchsi.com wrote:
> I am a little behind on my email, so please excuse the late response to this 
> thread.  I have always left a little room - 1/2 to 1 inch between the rotator 
> and the bottom of the mast.  Obviously I suspend the mast by a thrust bearing 
> at the top of the tower.  This facilitates rotator swapping - I just unbolt 
> the old rotator, tip it out the side of the tower, and swap in a new one.  I 
> have had lots of experience with HamIVs over the last few years and just this 
> week completed a Yaesu 2800 swap - hopefully this will be completely overbore.
>
> Anyway, the question - Since no one mentioned this ( leaving room between the 
> mast and the rotator) have I been engaging in a poor practice?
>   

Depends.  The Ham series should have some weight on them although it 
doesn't have to be a lot.  I leave space between the rotator (PST-61) 
and mast, but when it's clamped I release the thrust bearing tension so 
it only serves to align the mast. rather than holding it.  My rotator is 
quite a ways down in the tower. With that arrangement, differential 
expansion and contraction of the tower and mast could actually pull 
against the rotator at times which would not be good for it.  I believe 
ROHN used to even sell a bushing that didn't tighten onto the mast.

73

Roger (K8RI - ARRL Life Member)
www.rogerhalstead.com
N833R (World's oldest Debonair)