Siemens SITRANS LR 400 Instruction Manual page 16

Correct Installation in Mounting Nozzle
The bottom edge of the antenna must reach inside the vessel to avoid reflective
interference at the wall of the nozzle. Above flange size DN 150/6 inch, the antenna may
end in the nozzle unless the radiation cone (the extension of the antenna's angle) touches
the nozzle wall.
Page 12 SITRANS LR 400 – INSTRUCTION MANUAL DRAFT 7ML19985FH01