Siemens SIMATIC RF642A Operating Instructions Manual page 29

Antenna radiation patterns in the FCC frequency band
Directional radiation pattern USA (FCC)
The directional radiation pattern is shown for nominal alignment and a center frequency of 915 MHz.
Figure 7 Reference system
The half-power beam width of the antenna is defined by the angle between the two -3 dB points (corresponding to half the
power referred to the maximum power). Which range (in %) corresponds to the dB values in the patterns can be obtained
from this table .
Note that the measurements presented graphically below were carried out in a low-reflection environment. Deviations can
therefore occur in a normally reflecting environment.
SIMATIC RF642A
12
J31069-D0226-U001-A2-7618, 12/2010