At 03:36 PM 8/6/96 -0500, Dave Raymond-CSUS04 wrote:
> For whatever it's worth, N0AMI (Jim), located here in Des Moines
> recently replaced his Tailtwister with a G1000SDX rotor. The
> tailtwister had finally failed after six years of turning the large
> KLM Log Periodic (with the 40 meter kit). This antenna is on a 42'
> boom. Ths antenna, however, is well below the maximum wind load
> specified by Yaesu.
>
> We installed the G1000 with high hopes...we all thought the control
> box was rather nifty but we questioned the very light weight of the
> rotor itself. Upon the 100th day of operation, the G1000 failed. Jim
> has a weather station at his qth and had recorded no winds over 50
> mph. We pulled out the new G1000 and replaced it with a spare
> Tailtwister. After we got down on the ground, we discovered the
> problem. When you shook the G1000, it sounded like there were scores
> of loose pieces inside (probably bearings?). We didn't dare open it
> up!
>
> Sooo, based on that experience, I would think twice about using a
> G1000 to turn any heavy loads or antennas with long booms.
>
> 73,
>
> Dave
> WA0FLS
>
> P.S. The spare Tailtwister is still in place and working.
>
>
Hi Dave -- Are you sure about that wind area spec? My G-1000SDX book shows
2.2 square meters, or about 24 square feet -- I would've thought that KLM
was bigger. Also, they say in the book - and this seems to me a more
relevant spec - that the product of the rotating radius and the weight of
the antenna should not exceed 2020 foot/pounds. On a 43-foot boom, that KLM
probably weighs more than 100 pounds, no?
When I inquired on the contest and DX reflectors, I found a number of people
who had G-1000s with quite large loads - I think the biggest was a 40-2CD
and a Tennadyne 10-element 20-10 meter LP - with no failures reported.
Could it be you ran into a manufacturing error or a materials problem in
that particular unit?
73, Pete Smith N4ZR
n4zr@contesting.com
LOUDER is gooder....
|