Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx
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17.9.
Measuring Unexpected Velocities
In some cases, signals are from the wrong targets. A waving weed, aquatic animals, a
strong stationary reflector in the bed, slow-moving saltation targets or ripples on the surface
can all produce Doppler shifts that are not directly related to the water velocity.
The “field of view” of the Starflow QSD can extend for at least 5m along the beam in clean
water and reduces as the sediment load of the stream increases.
The beam can reflect from the surface underside and can detect different velocities than
those expected. This results in a distorted peak, or a double or multiple peaks in some
situations, the composite of all velocities seen along the path. Such sites may be unsuitable
for the Starflow QSD as the flow is not laminar.
