Effective geometry of a forward-scatter meteor system

Meteor detection using the radio forward-scatter technique is not equally sensitive to meteors from all directions. For 'long distance' forward scatter, an approximate formula for the 'geometrical' effectiveness of a meteor radiant is given by the following formula:

Geometrical effectiveness = sin 2h  x sin dAz (take the absolute value) 

where 

h = radiant elevation above the horizon
dAz = difference in azimuth between the Tx/Rx axis and the meteor  radiant

If we imagine a forward scatter system, with the Tx / Rx aligned along the y axis, then the approximate system effectiveness, due to geometry, is aligned as shown below.

The following java applet  shows an interactive version of this same diagram. Left click on the diagram to rotate the image, or right click for more options.