# aug2019

We've tried using a laser scanner from AO9 to measure the dish. There was talk of building a tower around ao9 so the laser scanner beam would make a smaller angle between it and the surface normal. This should help on the returned signal. The amount will depend on how diffuse the scattering off the dish is.

The setup would look like: I've plotted the measurements for various heights above the center of the dish, (.ps) (.pdf)
• Top plot:  angle to normal vs distance from center.
• When the angle is 0 deg you are looking perpendicular to the surface.
• When the angle is 90 deg you are looking parallel to the surface.
• Each color is for a different height above the center of the reflector.
• 135 meters would be something hanging about 1.5 meters below the center of the elevation rails (on the azimuth arm).
• Bottom plot: measurement distance
• For heights 0 to 10 meters above the dish the distance is a linear function of distance from the center (0 to 160 meters).
• The light blue line shows how the distance varies if you are hanging under the  center of the  elevation rails (135 to 175 meters).

The current height of ao9 is probably 1.5 to 2 meters.

processing: x101/projects/laserscanner/reflanglevshght.pro