53
MX 420 Installation and Service Manual
A. Power wire colors are red (+) and black (-). Refer to Figure 4.1 for wiring hookup.
Even though the navigator has a reverse polarity protection device, we recommend
that the installer observe proper polarity before hooking up the power leads. MX
Marine also recommends using a 2 amp. fuse in line with the red wire as close to the
battery as possible. This not only protects the navigator but also the cabling.
Navigator Grounding.
The electronics of the navigator are isolated from the external power supply. Connect
the navigator unit to ground to avoid static charge build up. This can be done in either
one of two ways:
1. Connect the Cable A shield to the boat’s
Seawater ground
.
2. Connect the grounding stud of the navigator to the boat’s
Seawater ground
.
Note
:
‘Seawater ground’ is any electrically conductive material that is
directly in contact with sea water.
MX421 GPS ANTENNA INSTALLATION
Antenna Location
The GPS smart antenna (MX421) should be mounted with a relative clear view of the
horizon. Do not, mount the antenna on top of a very tall sailboat mast, as this may
degrade the COG and SOG calculations, particularly when in DGPS mode. Ensure
the antenna is placed outside the beam path of transmitting radar (typ15
°
horizontally from the array’s center point) and INMARSAT satcom (A, B, C, or M;
typ10
°
from the array’s center point in any of the possible transmitting
directions and at least 5 meters from any side lobe or back lobe direction). The GPS
antenna should be mounted below and at least 5 meters away from these types of
antennas. Do not place it within 3 meters of a SSB or VHF radios or their antennas.
Antenna Options
Two antenna options are available for the MX420, namely:
•
GPS only smart antenna (MX421 or MX421-10)
•
Combined GPS and differential beacon smart antenna (MX421B or MX421B-10)
These antenna models look identical and they are wired the same way (refer to the
chart shown below). The antenna model is indicated on the serial number tag on the
underside of the antenna. The drive voltage to the antenna is 12 VDC +10%, and
normally provided by the MX420. However, power to the MX421 antenna may be taken
from the main battery supply.
Antenna Connector
The multi-pin connector at the bottom of the antenna housing provides the necessary
interfacing between the MX421 smart antenna and the MX420 CDU. Older production
MX421 antennas use 8-pin connectors while new build units (MX421-10) use 10-pin
connectors. The interface connections from pins 1 through 6 are common for all
MX421 configurations. Pins 7 & 8 are used for monitoring the beacon receiver status
(for the built-in beacon receiver) or for external RTCM correction. The additional two
pins on the newer production MX421 are used to output the 1 PPS signal as shown in
Summary of Contents for MX420
Page 1: ...Installation Service Manual MX420 Navigation System ...
Page 5: ......
Page 8: ...1 MX 420 Installation and Service Manual List of Components SECTION 1 LIST OF COMPONENTS ...
Page 9: ...MX 420 Installation and Service Manual List of Components 2 ...
Page 15: ...MX 420 Installation and Service Manual List of Components 8 ...
Page 17: ...MX420 Installation and Service Manual Technical Specifications 10 ...
Page 24: ...17 MX420 Installation and Service Manual SECTION 3 MECHANICALAND INSTALLATION DRAWINGS ...
Page 25: ...18 MX420 Installation and Service Manual ...
Page 32: ...25 MX420 Installation and Service Manual SECTION 4 ELECTRICALINSTALLATION DRAWINGS ...
Page 33: ...26 MX420 Installation and Service Manual ...
Page 49: ...42 MX420 Installation and Service Manual ...
Page 57: ...50 MX 420 Installation and Service Manual SECTION 5 INSTALLATION NOTES ...