- Closely follow the equipment manufac-
turer’s recommendations for antenna
placement and separation from other
types of antennas mounted on the boat. - When planning electronics installations,
keep in mind possible interference
sources in either direction.
You can use the above list to confirm that
the electronics specialist has installed your
system(s) correctly. Satcom systems are vulner-
able to both radio frequency and magnetic
interference. Satellite television receivers oper-
ate in the 1.5 GHz to 1.66 GHz frequency
spectrum, and they can cause interference with
cellular telephones (either 850 MHz or 1.9
GHz) and GPS (1.5 GHz). However, interfer-
ence goes both ways: the GPS or cell phone
can also interfere with television reception.
Other satellite voice and data systems, such
as the Inmarsat Mini-M system, also operate in
the 1.5 GHz to 1.66 GHz range, and are
equally susceptible to cross interference. In both
cases radar scanners can cause interference,
depending on the specific operating frequency.
installing communicationsand position-finding systems 147All satcom receivers use fluxgate, or elec-
tronic, compass sensors to help the antenna
track and aim toward the appropriate satellite.
In some units this sensor is mounted under
the same dome as the antenna, while in others
it is mounted elsewhere, typically under set-
tees, behind panels, etc. No matter where the
sensor is mounted, however, make sure it is far
enough away from sources of magnetic inter-
ference, including devices with permanent
magnets or electromagnets, high-current-draw
DC conductors, and large ferrous objects.
Remember that compass sensors (and GPS
antennas) must be mounted as close to both
the port-starboard and fore-aft centerlines of
the boat as possible to minimize the effects
of the boat’s pitch and roll and to provide the
sensor with as much stability as possible.
Finally, the NMEA electronic equipment
installation standard recommends that a plac-
ard be placed near this satcom sensor that
reads: “Magnetic Compass Area! Do Not
Install Or Store Magnetic Material Within
3 Ft.” That recommendation nicely sums up
the concerns with magnetism.The systems listed in Table 14-2 are strictly satellite communicationsoptions. DirecTV, a popular
land-based satellite company, is one of the most common service providers for boat-based systems as
well. Manufacturers of satellite television equipment include:
King Controls, http://www.kingcontrols.com
KVH, http://www.kvh.com
Raymarine, http://www.raymarine.com
Sea Tel, http://www.seatel.com
Shakespeare, http://www.shakespeare-marine.com
The two largest satellite radio service providers in North America are:
Sirius, http://www.sirius.com
XM Radio, http://www.xmradio.comSATELLITE TELEVISION AND RADIO