-
Notifications
You must be signed in to change notification settings - Fork 26
Hardware installation
The Navico radars are very easy to use with OpenCPN. All you need is a wired Ethernet connection.
You can add as many computers as desired, the system will allow operation from all connected MFDs (plotters) and computers.
In all installation packages (except Lowrance 3G USA) the scanner also ships with a small black box -- either a RI10 with NMEA 2000 input or a RI11 with NMEA 0183. It uses the data from the heading sensor on the NMEA network to add this to the radar data.
- The Navico plotters require heading input to the RI-10/11 for MARPA operation.
- The plugin uses this heading as the "best" source of heading for radar overlay.
This box also helps isolating the system electrically, and will improve protection of the computer from damage in case of electrical storms (lightning.)
If you already have a Navico MFD installed the installation consists of:
- Installing an Ethernet switch, or a WiFi router with a built in Ethernet switch. You need a wired port for each device -- the radar, the MFD(s) and the computer running OpenCPN.
- Connect all devices to the switch.
In all cases you will need at least one RJ45 to Navico radar connector cable. The cheapest solution is to cut Navico Ethernet cables with two yellow connectors at both ends, and crimp a RJ45 connector onto both halves.
Follow the instructions here to fabricate these: http://yachtelectronics.blogspot.nl/2010/05/lowrance-yellow-ethernet-cabling.html.
So for the most common case where you have a single MFD connected to a radar scanner:
- Cut the ethernet cable between MFD and scanner.
- Crimp on two RJ45 connectors.
- Insert these into a switch.
- Connect the computer to the switch as well.
If your scanner came with a RI10:
- Cut the supplied Navico ethernet cable in half.
- Crimp on a RJ45 connector.
- Insert the RJ45 connector into the computer's Ethernet port or a standard Ethernet switch and the other side into the RI10. Install the scanner as detailed in the Navico installation instructions.
If you bought a USA Lowrance 3G scanner:
- Insert the RJ45 connector from the radar scanner into a standard 100 Mbit switch.
or
- Cut the supplied Navico conversion cable that has a RJ45 female connector and a yellow Navico connector in half, and replace the yellow connector with a RJ45 connector.
We recommend always using a 100 Mbit switch in this setup to provide some electrical isolation between the scanner and the computer. We don't know whether the connection between the radar and the RI10 uses the four other wires for some non-Ethernet purposes, so some damage may occur if you insert the radar cable directly into your computer.
If you are going to use a switch you may as well use a Gigabit switch. The scanner has a 100 Mbit interface, but a Gigabit switch will use slightly less power than a 100 MBit switch. You should probably also use one that has a 12V input which can be powered directly from the 12V house battery (or a DC/DC converter if you have a 24 V house battery bank.)
The author uses a 5 port Netgear GS105 which according to Netgear: Both GS105 and GS108 support the latest Energy E cient Ethernet (IEEE 802.3az) standard, which reduces energy consumption when there is light traffic on an active port or when there is no link or no activity detected. It can further save energy when a short cable (<100m) is used. Energy savings lead directly to cost savings in operation.
Note: make sure you get the metal cased GS105/GS108 that uses 12 V input. There are now also other models with a plastic case that have a 5 V input, which requires an extra DC/DC converter.
The multicast transmission system used by the scanner means that transmission over WiFi must happen at the lowest rate that any device connected to the WiFi network is capable of. For 802.11b and g this rate is 1 Mbit/s. Since the radar data is ~ 1 Mbit/s as well this means it does not work well at all.
The solution is to either:
- Modify the base rate to be higher. This reduces the maximum range of your WiFi network for all devices.
- Get a faster WiFi network, for example 802.11a or 802.1ac (5 GHz). This has a much faster base rate (6 Mbit/s).
Unfortunately, most WiFi routers do not allow you to change the base rate.
If yours is Linux based and uses hostapd you can try the following procedure. Edit the following section in hostapd.conf. The example should disable basic rates 10 and 20 (= 1 and 2 Mbit/s):
# Basic rate set configuration
# List of rates (in 100 kbps) that are included in the basic rate set.
# If this item is not included, usually reasonable default set is used.
#basic_rates=10 20
#basic_rates=10 20 55 110
basic_rates=55 110
#basic_rates=60 120 240
The author has had no success with trying the above as the hostapd he is using seems to ignore these instructions, and has resorted to using a 5 GHz network instead.