RF interference
Certain third-party external electrical equipment can cause Radio Frequency
(RF) interference with GNSS (GPS), AIS or VHF devices, if the external
equipment is not adequately insulated and emits excessive levels of
electromagnetic interference (EMI).
Some common examples of such external equipment include LED lighting
(e.g.: navigation lights, searchlights and floodlights, interior and exterior
lights) and terrestrial TV tuners.
To minimize interference from such equipment:
• Keep it as far away from GNSS (GPS), AIS or VHF products and their
antennas as possible.
• Ensure that any power cables for external equipment are not entangled
with the power or data cables for these devices.
• Consider fitting one or more high frequency suppression ferrites to the
EMI-emitting device. The ferrite(s) should be rated to be effective in the
range 100 MHz to 2.5 GHz, and should be fitted to the power cable and
any other cables exiting the EMI-emitting device, as close as possible to
the position where the cable exits the device.
Compass safe distance
When choosing a suitable location for your product you should aim to
maintain the maximum possible distance between the product and any
installed compass. This distance should be at least 1 m (3 ft) in all directions.
For smaller vessels it may not be possible to achieve this distance. In this
situation ensure that the compass is not affected by the product when it is
powered on.
EMC installation guidelines
Raymarine equipment and accessories conform to the appropriate
Electromagnetic Compatibility (EMC) regulations, to minimize electromagnetic
interference between equipment and minimize the effect such interference
could have on the performance of your system.
Correct installation is required to ensure that EMC performance is not
compromised.
Note:
In areas of extreme EMC interference, some slight interference may be
noticed on the product. Where this occurs the product and the source of
the interference should be separated by a greater distance.
For
optimum
EMC performance we recommend that wherever possible:
• Raymarine equipment and cables connected to it are:
– At least 1 m (3.3 ft) from any equipment transmitting or cables carrying
radio signals e.g. VHF radios, cables and antennas. In the case of SSB
radios, the distance should be increased to 2 m (6.6 ft).
– More than 2 m (6.6 ft) from the path of a radar beam. A radar beam
can normally be assumed to spread 20 degrees above and below the
radiating element.
• The product is supplied from a separate battery from that used for engine
start. This is important to prevent erratic behavior and data loss which can
occur if the engine start does not have a separate battery.
• Raymarine specified cables are used.
• Cables are not cut or extended, unless doing so is detailed in the
installation manual.
Note:
Where constraints on the installation prevent any of the above
recommendations
, always ensure the maximum possible separation
between different items of electrical equipment, to provide the best
conditions for EMC performance throughout the installation.
Suppression ferrites
• Raymarine cables may be pre-fitted or supplied with suppression ferrites.
These are important for correct EMC performance. If ferrites are supplied
separately to the cables (i.e. not pre-fitted), you must fit the supplied
ferrites, using the supplied instructions.
• If a ferrite has to be removed for any purpose (e.g. installation or
maintenance), it must be replaced in the original position before the
product is used.
• Use only ferrites of the correct type, supplied by Raymarine or its
authorized dealers.
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