1. Depending upon the model, activate the transponder by swivelling the pin or otherwise sending a signal, and mount the transponder in the tree at 1.3 m (the TRP height) facing the direction where measurement will be taken.
   
   
2. Select a point, preferably as far away from the tree as the tree is tall and where the required point (eg tree tip) can be seen. (Note that the Vertex does not correct for leaning trees, so you must move out in a direction perpendicular to the plane of any lean of the tree).
   
   
3. Press the ON/OFF button and check the TRP height is set at the 1.3 m.
   
   
4. Ensure that the internal temperature of the Vertex is the same as the external temperature - wait until they have equilibrated is there is any doubt.
   
   
5. Sight at the transponder, press and hold the red button until the red sighting light begins flashing. (The Vertex has measured the horzontal and slope distance from the transponder to your eye).
   
   
6. Sight to the desired point and hold the red button until the sighting light stops flashing (The Vertex calcultes the height and displays it - the hight is calculated as the TRP + height above the transponder).
   
   
7. Sight to up to two more positions and repeat the above step - all three heights can be read from the display.
   
   
8. Check all readings and calculations.

[vertex.htm] Revision: 6/2001
Cris.Brack@anu.edu.au