Step 1.  Google Earth

1.1   Google Earth >> Tools >> Options
 - Configure to display Latitude and Longitude in Decimal Degrees.
 - Stop GE from automatically tilting the view as it zooms.

TIPS:
A. In Win 7, use the + key combination to
    auto-scale and locate the active window to a split screen.
B. Right-mouse-click the Placemaker, to bring up the options
    and access its properties.(On a Mac: Get Info)

1.2   Drop a marker at your location.
1 - Paste the Lat/Long coordinates, Press [Search].

2 - Drop a marker near your location and drag it to
     the exact position your antenna will me mounted.
     [Add], [Placemark].
     Name your Placemarker for future reference.

3 - Highlight the Coordinates without the "°" and to copy to the
     notes box, as shown above.
     This can make for easy copy/paste in a later step. 

1.3 Leave Google Earth open.
You'll be using this later, so minimize or re-size without closing it. 

1.4  Save your work.
Its a good idea save your place-mark by clicking
"Save my Places" on the "File, Save" menu of Google Earth.
This saves all your work in Google Earth, so if your PC or Google Earth crashes while your doing this research, you wont need to start all over again.

1.5  Alternatively , Email or Save the KMZ file in Google Earth.

A. Drop a Placemark at your location
B. Right mouse click on the Placemark.
C. Select "Save Place As" or  "Email".  

Notes:
The Site Coordinates shown in the bubble are in AGD66 datum format whereas the coordinates accepted by Google Earth use GDA94/WGS84. The difference between these datum types places ADG66 about 200m south east of WGS84. Luckily the KML link of the Site Bubble converts the coordinates and opens the location in Google Earth using the correct datum type.
It is very important to locate the exact position of both the tower and your location because a difference of 10m in position might produce a significant difference in signal strength result, depending on the terrain.
Please remember to Save your places at this point.