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Old 19-08-2016, 05:49   #1
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Can radar data be repeated to 2nd PC?

All,

If I have a Lowrance or Garmin unit connected via Ethernet to my main PC, can OpenCPN repeat that data to a second PC the same way it can send GPS data, etc.?

Thanks,

Shrimp
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Old 19-08-2016, 06:20   #2
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Re: Can radar data be repeated to 2nd PC?

I guess no because not OpenCPN see the radar data but the plugin does.

Gerhard
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Old 19-08-2016, 06:54   #3
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Re: Can radar data be repeated to 2nd PC?

Quote:
Originally Posted by cshrimpt View Post
All,

If I have a Lowrance or Garmin unit connected via Ethernet to my main PC, can OpenCPN repeat that data to a second PC the same way it can send GPS data, etc.?

Thanks,

Shrimp
No, OpenCPN is not going to repeat the radar data and there is no need to do it, the traffic is UDP multicast so it gets to all the clients on the network if they are set up correctly.

Pavel
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Old 19-08-2016, 07:21   #4
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Re: Can radar data be repeated to 2nd PC?

that works across interfaces or you create a bridge?

The plugin could do more advanced things like compress the data and store or re-transmit it more efficiently or across interfaces, but currently doesn't.
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Old 19-08-2016, 07:27   #5
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Re: Can radar data be repeated to 2nd PC?

Sean...
I don't understand your question, why would you be creating a bridge or use more ethernet interfaces on the same machine? Why would you care about compressing data etc. on a local cabled ethernet, which is what this stuff uses?
Yes, if you wanted to get the data to a slow wi-fi or transmit it off-board over internet, you would start thinking about something like this, sure...

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Old 19-08-2016, 12:58   #6
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Re: Can radar data be repeated to 2nd PC?

Quote:
Originally Posted by cshrimpt View Post
All,

If I have a Lowrance or Garmin unit connected via Ethernet to my main PC, can OpenCPN repeat that data to a second PC the same way it can send GPS data, etc.?

Thanks,

Shrimp
In other words. You may instead try a switch to share the network traffic between several PCs. For example a Netgear GS105 which can be directly supplied by your 12 V system (< 2.7 W). Or if you already has router you can use its switch function.
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Old 19-08-2016, 17:19   #7
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Re: Can radar data be repeated to 2nd PC?

Shrimp, et al...

Displaying Garmin radar data on two PCs should "just work", at least after a fashion. Set up one PC as a Garmin Radar PlugIn master, and the other as a slave. The master will set range, gain, etc. Of course, the slave PC must be showing exactly the same chart center and scale for the overlay to make much sense.

Not tried, so YMMV.

Good Luck
Dave
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Old 19-08-2016, 18:23   #8
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Re: Can radar data be repeated to 2nd PC?

If you want to repeat OpenCPN on another computer then a VNC client should be able to do that. Google Apps supplies a VNC client called VNC Viewer for Google Chrome and there are other free VNC clients available. With a VNC client the display would match exactly the master PC.
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Old 19-08-2016, 19:23   #9
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Re: Can radar data be repeated to 2nd PC?

Sean's ideas for compression and reducing triangulation in the radar image would be useful for sending this data via wifi to opencpn. There are some other network protocal issues which were discussed and muttinick probably knows them best. Furuno has radar over wifi and I wouldn't be surprised if Raymarine had it now.
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Old 21-08-2016, 07:58   #10
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Re: Can radar data be repeated to 2nd PC?

The Navico radar plugin works fine over WiFi as long as you use something with > 1Mbit capacity for multicast. I guess the same would be true for the Garmin radar. In practice, the easiest way to do this is to use 802.11a (= 5 GHz) or better. Buying a $ 50 WiFi router is a lot more cost effective than us poor developers spending many hours producing a compressed radar image.

With the Navico radars (& plugin) there is no master/slave concept, all stations can control the radar and all other stations, including any Navico MFDs, will show the new status.

Besides, if you really want to you can already do this by using a remote display technology like VNC or whatever else is out there. You'd just see exactly the same screen, but that is probably what you want in these cases. You can also use a small tablet instead of a full blown PC. [Edit: I missed @transmitterdan already mentioning this.]
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Old 21-08-2016, 17:48   #11
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Re: Can radar data be repeated to 2nd PC?

Merrimac, that 5mhz 802.11a router with wifi will work is good news to me. The last report I recall was that the router had to support some special protocol which required you to basically install an opensource router program onto your router and not all routers were compatible.

I've asked this before and gotten answers, but things change and develop.

Since I've installed a B&G 4G with RI10 and a Zeus Touch following the manuf install and everything seems to be working, what is the best way to get the radar signal to opencpn and B24radar_pi such that both could work?
I imagine a router would be needed whether or not it was by wifi? What is best suggested way of connecting the router?
One other hurdle I have at the moment is the need to connect the yellow wire to turn the radar on. Currently that power connection is taken care of by the RI10 and going out over the proper ethernet wire, but with the router in between, the issue of the yellow wire power might end up going through the router which I believe would likely fry the router. So this setup is not really a simple one I think.

I'd be very interested in some details to follow. Perhaps this is documented in the User Docs under the plugin?
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Old 21-08-2016, 18:02   #12
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Re: Can radar data be repeated to 2nd PC?

PS I'd also like to be able to send nema0186 data from the n2k bus, perhaps via the zeus nmea 0183 wires, out to a tablet or PC with opencpn on it.

Would the radar data preclude the nmea0183 data being available?

By the way my 1994 Raymarine Wheelpilot's fluxgate seems to work for giving slow radar overlay onto charts on the Zeus. A RM ST1 to STNG Converter was used and a STNG backbone cable modified with a Mareton Micro N2K adapter to connect to the N2K bus and eventually send the heading data over a short N2K to simnet connection into the Radar RI10. I was actually surprized it worked passibly for a slow sailboat.
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Old 22-08-2016, 00:19   #13
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Re: Can radar data be repeated to 2nd PC?

Whatever you do, keep the RI-10/11. Not only does it make the installation easier, it is required to make the installation safe and "in spec". The Lowrance version came without one in the beginning, but cannot legally be installed in the EU this way. I guess this has to do with more stringent (electric) noise and hazard laws and regulations. Also it is the only way to inject heading into the radar data, and although the plugin likes this and uses it as the best source of radar heading, your plotter requires it for overlay.

The "yellow ethernet plug" cables are the best place to start your intrusion as they contain just four wires and those four are all plain Ethernet TX (100 MBit) wires.

I still suggest using wired ethernet. This will give you the lowest power consumption, lowest cost, best performance and best success rate. Get a simple 5 or 8 port 100 MBit or Gigabit switch. Gigabit switches will use less power (!) I recommend the Netgear GS305 or GS308. Cheap as dirt, uses less than 2 W with all ports in use at 100Mbit.

Just split one of your existing Navico ethernet cables at a convenient location, add 2 RJ45 connectors and put them in the switch, as well as your PC.

Alternatively, get a WiFi Accesspoint @ 5 GHz or if you really must use 2.4 GHz a Linux based one that you can set the "base rate" for. See https://wireless.wiki.kernel.org/en/users/documentation/hostapd#wireless_interface
and https://w1.fi/cgit/hostap/plain/hostapd/hostapd.conf

See the following section:

Code:
# 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=60 120 240
So if you insist on using 2.4 Ghz something like this:

Code:
basic_rates=55 110
Note that the 5 GHz 802.11a base rate is 60 = 6 MBit = plenty.

And yes, of course you get a free NMEA 0183 server with your plotter. Just read the doc for the plotter.
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Old 22-08-2016, 07:11   #14
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Re: Can radar data be repeated to 2nd PC?

Merrimac, thank you for the good advice. I guess I'll use the hardwired switch alternative for radar to a PC with Opencpn and connect the Raymarine Instruments with a gadgetpool.de Seatalk Link to USB. Later I'll try to get wifi for instrument data.
May I add your post as an addendum to the plugin user documentation?
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Old 22-08-2016, 14:03   #15
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Re: Can radar data be repeated to 2nd PC?

I'm in the process of rewriting the doc page(s) but any help is welcome. I think we should have a separate radar hardware page.
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