Rf Interference; Electrostatic Discharge - Furuno Inmarsat FleetBroadband FELCOM251 Installation Manual

4. GROUNDING AND RF PROTECTION
The ground cable must be connected at one of the mounting/grounding bolts on the
antenna in the following figure. Remember to seal the joint with protective coating to
avoid corrosion.
Ground cable
4.10

RF Interference

Interference induced from nearby RF transmitters might cause system failures and in
extreme cases permanent damage to the FleetBroadband equipment. If there are
problems with interference from HF transmitters, it is advisable to mount ferrite clamps
on the coax cable in order to provide suppression of induced RF. The ferrites will have
no effect on the differential-mode signals but increases the impedance in relation to
common-mode RFI.
Recommendations
Use 1-5 pcs. hinged clamp cores (e.g. the RFC or SFC series from Kitagawa) mount-
ed on the antenna cable near the antenna.
4.11

Electrostatic Discharge

In addition to the RFI attenuation, mounting ferrite clamps on the antenna cable will
also slow the fast rate-of-rise of an electrostatic discharge current pulse. This might
be an issue during installation (antenna cable disconnected) where different electrical
potentials have had the chance to build up between the Communication Unit and An-
tenna Unit.
We recommend mounting 1-5 pcs. hinged clamp cores (e.g. the RFC or SFC series
from Kitagawa) on the antenna cable near the antenna.
4-16
Isolating shoulder bush
Plain washer (stainless steel)
Ground cable
Serrated washer (stainless steel)
Plain washer (stainless steel)
Spring washer (stainless steel)