The recent round of 80 to 90 MPH straight line winds in our area has caused a
misalignment of my rotator direction indicator and the actual antenna position.
First, the indicator is centered on North and can go on the meter to the (left)
South of West and on the (right) South of East.
Right now playing with the calibrate knob and turning the antenna, the azimuth
indicator needle will travel to and show South (of East) but the antenna and
rotator stop at about the 130 to 140 degree position and remain there, tracking
of the sweep of the indicator needle seems linear from North to the stop point.
But the antenna will not advance past 130 or so to due South 180 degrees.
On the other side of the indicator when I rotate back past North toward South
(of West) the indicator arrives at South with a deceleration of the degrees
traveled compared to the indicator as the antenna moves past north to north
west then west, and finally ends up at south west say 210 to 220 and stops shy
of South.
I initially tried to use the calibrate button to adjust this but the above
results are the best I can get.
This is Alliance Model HD 73 and has been pretty bullet proof until now.
The rotator initially torques on top of my Aluma tower top section in heavy
wind storms until my antenna guy put a couple of self tapping large screws
through the top plate and against the lower bell housing of the rotator to
limit the rotation of the rotator on its mounting pipe. This rotator sits on
top of the top plate using a lower pipe mount, the bottom of the bell housing
just sets on the top plate while the pipe goes down into the tower and is
secured to the tower legs using U bolts to all three tower legs.
There are two options I am thinking about to correct the alignment.
First, place the indicator and rotator as far to the South (of West) position
and then loosening the mast clamp and manually align the antenna to true south
since the correspondence of degrees measured to degrees turned is different on
this side of the rotation.
Or Second, place the indicator and rotator as far to the South (of East)
position and align the antenna to true south loosening the mast clamp.
Which way am I safe to presume will correct full range of rotation and more
accurate correspondence to the measurement scale? I can get someone to turn
the antenna in the rotator to true South when the indicator is in either the
South (of East) or (West) position.
Anyone familiar enough with this rotator to assist?
The antenna is A3S so precise pointing is not absolutely required, rather
ballpark pointing. At this point I cannot cover the last 30 to 60 degrees
across the south stops.
And if you know the bolt size on the bolt heads securing the mast pipe I can
send my painter friend up his ladder against the tower, as climbing this small
tower is impossible, with the correct socket! So he can loosen then move and
tighten the antenna into place.
If I am incorrect in this entire diatribe please let me know your ideas. I
plan to attempt this move tomorrow evening.
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|