Using Google Earth to observe RF Paths                     28 March 09
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I was amazed at how easy this is.  First, just download Google Earth.
Run it.  When the Earth appears, just zoom in to anywhere you want to
see.  When you get zoomed in and want to see terrain, then at the
bottom of the Layers side bar, click Terrain to ON.

Now TILT the map horizontal by clicking on the UP pointing arrow in the
upper right corner compass display.  Once you get the map towards
horizontal, you can use the left and right arrows to turn the view
clockwise or counter-clockwise.  Use the smaller arrow set to move
around in latitude and longitude and use the SLIDER bar (or your mouse
roller) to raise or lower your observation altitude.

MARK YOUR POINTS:  Next mark your points of interest so they are easy 
to find again.  Use the PUSH-PIN tool to do that.  Now add a LINE-OF-
SIGHT link by clicking on the "ADD PATH" item on the tool bar.  It 
looks like 3 little squares connected by two lines.  When the menu 
comes up, just use your mouse to click on both ends of the link.  It
appears that you can make more-and-more such points, but this is of
no value for our point0to-point RF purpose.  Apparently this tool is
used for setting a FLIGHT-PATH for later flying from point to point.

Finish your path by editing a name.  And be sure to pick the ALTITUDE 
tab to give your path 3D appearance.  SLide an altitude, then select
ABSOLUTE height and EXTEND PATH TO GROUND.

SAVE YOUR POINTS:  Use the FILE SAVE menu to save your points.  Then
you can also use FILE SAVE IMAGE to save a favorite image.

NOTES:  Unfortunately, this tool does not appear to let you enter any
path other than level.  So I take the middle height between the two
end points for the path altitude so that I can see how much it clears
the GROUND in the middle of the path.  That is usually where your 
path will have clearance problems.  If the clearance issue is closer
to one end than the other, then interpolate the height.

NOT RF PATH:  Of course, this is not a true RF path determination
since it probably uses the normal 1/1 visible earth curvature model 
instead of the usual 4/3rds earth curvature model used for RF.  Also
it does not take into account Fresnel zones which can enhance or
deminish the path depending on clearance to other objects.


But its free, and easy to use from anywhere on any PC you have sitting
near by, plus it gives fantastic views!

I am a complete newbee to this of course, so anyone that can improve
on these suggestions, please speak up.

Bob, WB4APR