R&S ENV432
Preparing for Use
User Manual 1326.6492.04 - 03
E-17
4.5.1 Avoiding Grounding Loops
To avoid grounding loops, the V-network should be grounded only once in the test
setup, if possible. An example of using a protective earth choke (PE choke) was
already given above (ensuring that the RF reference ground is not impacted by
disturbance voltages from an industrial network).
several V-networks ("V-NNB"), source: CISPR 16-2-1:2008-10 (Edition 2).
Fig. 4
Arrangement of PE chokes to avoid grounding loops
PE chokes for currents up to about 30 A are common. In case of higher currents, you
can make them yourself by using ferrite toroidal cores. The following rule applies: In
case of a short circuit, the voltage drop at the PE choke must not exceed 4 V.
A sheath current absorber for the coaxial cable can be implemented as shown in
. The figure illustrates the attenuation of an absorber with the following material:
Core material:
N30; Al = 5400 nH
Dimensions:
Toroidal core 58 mm x 40 mm x 17 mm
EPCOS order no: B64290-A40-X830
Number of turns: 20 (RF cable)
