Beam Spreading; Polarization Effect; False Reflections - Siemens SITRANS LR 300 Instruction Manual

Beam Spreading

Polarization Effect

Mounting the unit too close to a wall may cause echoes to disappear at specific levels
due to wave cancellation. A strong false reflection from an internal tank obstruction can
be reduced or eliminated by rotating the unit to reduce this polarization effect.

False Reflections

Flat obstructions and struts perpendicular to the emission cone cause large false
reflections. They reflect the radar signal with high amplitude. Round profile interfering
surfaces diffuse reflections of the radar signals and cause false reflections with low
amplitude.
Minimize false reflections first by rotating the instrument for best signal (lowest false
echo amplitude). Then use the TVT shaper parameters (P831, 832, 837 and 838) to prevent
false echo detection.
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Keep the emission cone (12
o o
20 or 28 , depending on
configuration), free of
obstructions.
(100mm [4"] horn antenna)
(rod antenna or 150mm [6"]
horn antenna)
(200mm [8"] horn antenna)
SITRANS LR 300 – INSTRUCTION MANUAL
Due to the polarization effect of
the microwave signal related to
the wall of the vessel, we
o
recommend locating the
,
SITRANS LR 300 a minimum of
30cm (1') away from the sidewall
for every 3m (10') of vessel
7ML19985CL02