[TowerTalk] RE : Mast for rotator at bottom of tower?

[Peter Voelpel]

Jos,

I used a brand new GS-065 bearing on top of a small tower to hold the 6m
long steel mast and a 5-element 20m yagi at 12m, I used the rotator sitting
at the 6m level for rotation only.
Weight of mast, antenna and cable was about 90kg.
After about a year I took the whole system down as I built a bigger tower.
When I turned the thrust bearing by hand it was a different feel of turning
then on the beginning, a bit sticky.
When I dismantled it I found no grease at all anymore and already heavy worn
racings by the balls.
On the new tower I use a TB3 bearing, much better, also using a lubrication
fitting with it which was already prepared for.
Perhaps your system is not that heavy, but check the presence of grease
regularly!

73
Peter, DF3KV


-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of hermans
Sent: Dienstag, 13. Juni 2006 00:18
To: 'marc wullaert'; towertalk at contesting.com; 'Bill Turner'
Subject: [TowerTalk] RE : Mast for rotator at bottom of tower?

Bill Marc,

I dont agree completely Marc, as far as I can admit that the Yeasu 2800 has
been constructed the same way as the G-2000RC who is an older version with
AC motor.
My rotor is bolted on a removeable and calibrated platform at a hight of 5
meter. ( Tell you why later ).
I agree that a steel mast is quite heavy to be supported continously by the
sole motor ( Max dead weight 250 Kg or 550 lbs max momentary vertical weight
800 Kg or 1760 lbs).
 But one can, as I, use a thrust bearing near the top. ( Yeasu GS-065 ) max
diameter 65 mm and clamped with 8 bolts. I inserted even steel straps as not
to tighten de bolts on the mast itself.
Further I dont use a steel mast, but aluminium, 50 mm diam. The first and
the last section are 5 mm thick, the others only 3 mm thick.