Siemens SIMATIC MOBY D System Manual page 52

Planning the MOBY D system
4.3 Installation guidelines
Flush-mounting
Flush-mounting
52
Problem
Flush-mounting of MDS and SLG / ANT Dx
is possible in principle. However, the size of
the transmission window is significantly
reduced. The following measures can be
used to counteract the reduction of the
window:
Remedy:
Replace the non-metal spacer below the
MDS with a larger one.
MDS and/or SLG / ANT Dx must be at least
50 mm higher than the surrounding metal.
(At a distance x ≥ 600 mm from metal, the
field is no longer noticeably affected.)
Remedy:
Increase the non-metal distances a and b.
As a rule of thumb:
Select values for a and b that are larger

by a factor of 2 to 3
Increasing a and b has a greater effect

for antennas/MDS with a large limit
distance than for antennas/MDS with a
small limit distance.
System Manual, 01/2010, J31069-D0147-A6-7618
MOBY D