[TowerTalk] Recommendation for mast on bottom mount rotator

[K8RI on TowerTalk]

> I'm going to move my rotator to the bottom of my 80 foot tower and
> would like recommendations for the mast. I will support it at the top
> with a thrust bearing, and at least one, possibly two, non-thrust
> bearings part way down to prevent side to side movement.
>
> My question is what would be a good mast material? It would only have
> to support it's own weight and I'm wondering if 2 inch water pipe

Remember this mast has to do basically what the top mast does. It is one 
long torsion bar.
That and with a thrust bearing at the top the tower will end up supporting 
all the extra weight of the masting.

Also with the thrust bearing at the top and the rotator some where near the 
bottom you may end up with different expansion between the mast and the 
tower. Will this add extra load to the rotator or pull down creating an 
extra load on the tower?

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com

> would be suitable? How about 2 inch EMT? The upper mast section which
> actually holds the antenna is high-strength steel.
>
> I would drill and pin the couplers to keep them from coming loose. The
> antenna is a four element quad, about 65 pounds.
>
> Is there a better way? I want to do it right, so within reason, cost
> is not a factor.
>
> All suggestions appreciated.
>
> Bill, W6WRT
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