the table shows the measured values and pictures of where the
measurements were taken (at the cross hair).
The theodolite was not placed at ao9 (the
center of the 3 towers) because there is no longer any scaffolding
that lets you get up
to where the theodolite is mounted.
Instead we placed the tripod about 8
feet away from the center of the 3 towers west toward T4. We
assumed that spinning in azimuth at a fixed elevation was not
going to make a large error if we were not at the center ... WRONG:)
Since the tm50 measures distance and angles we could have figured this out before....
The hf Anchor on T12 should be at the same vertical height as the anchor on T8.
The corrected measurement shows that the old measurement
(swinging the theodolite in azimuth while not at the tower center)
is 7.37 feet to low.
Using the bar, the old measurement placed the anchor 40" below the step back.
The correct position should be -40" + (7.37*12=88.44") =
48.4 inches above the stepback.
This number is hopefully correct. We should really put the scaffolding around AO9 and repeat the measurement from the center of the 3 towers.
One question i have is that the anchor on T8 looks to be below the old step back (which is no longer there). If all of the step backs are at the
same height then why is this new measurement saying the T12 anchor should be 48.4" above the step back?..(we'd better find some scaffolding for ao9!!).
Unfortunately this means that the anchor on T4 has been placed in
the wrong position.