Siemens SITRANS L Operating Instructions Manual page 193

Height from bottom of horn to sensor reference point as shown: see dimension drawing.
a)
-3dB in the direction of the polarization axis. For an illustration, see Polarization reference
b)
point (Page 29).
SITRANS LR250 with FOUNDATION FIELDBUS
Operating Instructions, 09/2021, A5E32221411-AH
Dimension drawings
12.5 Stainless steel threaded horn antenna
193