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forms an elliptical pattern on the target area . The beam’s size
depends on the distance between the antenna and the target . The
horizontal beam width is 5 .5° . The detection area becomes larger as it
becomes farther away from the antenna . The example below shows
a spot size of approximately 2 feet (61 cm) in diameter .
Figure 5.1
Radar beam detection area
When you point the SVR™ about 10 feet (3 meters) from the water
surface, it measures an elliptical beam pattern of approximately
2 feet (61 cm) in diameter . Keep this in mind when making
measurements of a stream width .
5.2 Selecting the Correct Site
To obtain the most accurate information on flow rate selecting the
correct location to position the SVR is important . For best results the
SVR should be positioned where the water flow is constant and free
from disruptions . Obstacles in the flow that create eddies or swirls
such as areas that have large rocks or man made objects that disrupt
the smooth flow should be avoided . Also to be avoided are areas
where the sides of the river or stream narrows, widens or curves since
the rate of flow will different at these locations . A proper location is
where the channel of the river or stream is not influenced by objects
in the water and where the width of the channel is representative of
the overall length of the river or stream . The following diagrams show
the locations to avoid and where best to position the SVR .
Poor Location diagrams
