Which radar will perform best with Opencpn?

[Hakan]

Originally Posted by Dockhead

Thread drift, but are you finding that MARPA from the 3G is working? I find it useless on my 4G set, worse than the MARPA implementation on my ancient steam-powered Raytheon radar.

What kind of compass are you using? I have sometimes wondered whether the poor MARPA is a result of poor compass stabilization (rather than poor bearing discrimination of the radar). It can't be the target discrimination or signal processing, because the guard zones are supremely useful, with hardly any false alarms. I have an Airmar H2183 compass but will be replacing it next year with the new Furuno satellite compass, hoping this will help a few things in my system including this.

I've a 3G and both MARPA and ARPA works as good as the 3G can supply stable echoes. It's of course easier for a supervised zone where a temporarily disappearing echo will reestablish the ARPA target when needed. Now is my scanner mounted on the aft hoop not more than barely three meters above the water surface so bigger waves can hide distant targets.

At the speed of a sailing boat I think the compass update rate is of minor importance for the radar_pi ARPA functionality. It's not critical in the same manner is an inbound function in a scanner.
I've a home made electronic compass and the update rate I've set to 2 Hz. Of course is a satellite compass a very good thing for many reasons. Not less a stable GNSS. I'm often searching to find a device suitable for my wallet.

[Hakan]

[QUOTE=Franziska;3306301We will rewire our arch next summer and I'd like to put a suitable cable in even if we do not have the radar yet...[/QUOTE]

Dockhead was answering but to extend it a little: Yes, you can prepare with an ordinary Ethernet patch cable and a 12 V supply. If you will do it as best as possible chose a shielded cable called FTP--- (STP will of course do but is exaggerated.) Quality CAT5 is really good enough. The signals from a radar scanner is not sensitive.

[Dockhead]

Originally Posted by Hakan

I've a 3G and both MARPA and ARPA works as good as the 3G can supply stable echoes. It's of course easier for a supervised zone where a temporarily disappearing echo will reestablish the ARPA target when needed. Now is my scanner mounted on the aft hoop not more than barely three meters above the water surface so bigger waves can hide distant targets.

At the speed of a sailing boat I think the compass update rate is of minor importance for the radar_pi ARPA functionality. It's not critical in the same manner is an inbound function in a scanner.
I've a home made electronic compass and the update rate I've set to 2 Hz. Of course is a satellite compass a very good thing for many reasons. Not less a stable GNSS. I'm often searching to find a device suitable for my wallet.

I don't know if you've seen the new Furuno sat compass, but it is a breakthrough -- for under $1000 in the U.S. I'm buying it for my boat as a Christmas present


MARPA works like crap with my radar; I don't even bother with it. Even very large very stable targets. I suspect the software is bad; I've heard many other people with the same complaint. But I do allow that compass data -- not necessarily the refresh rate -- might be part of the problem. My H2183 (which cost almost as much as the new Furuno sat compass) supposedly gives 2 degree dynamic accuracy, gyro stabilized, with refresh rate at 10hz. But the real life performance seems worse than that.



So maybe you are using MARPA (and how do you have ARPA?) computed elsewhere, than in the radar itself?

[Bill O]

Originally Posted by Dockhead

I don't know if you've seen the new Furuno sat compass, but it is a breakthrough -- for under $1000 in the U.S. I'm buying it for my boat as a Christmas present

Does the Furuno sat compass work w/ocpn? There was some discussion w/it on CF earlier this year, but never saw confirmation it interfaced well.


Have a new halo 20+ installed and am anxious to see how well the MARPA works when the weather gets warmer and can get away from the dock.

[Dockhead]

Originally Posted by Bill O

Does the Furuno sat compass work w/ocpn? There was some discussion w/it on CF earlier this year, but never saw confirmation it interfaced well.. .

Why wouldn't it? HDG is ordinary network data like anything else. The Furuno compass gives normal N2K PGN's like any other compass. Of course to get ANY N2K data into O you need to convert to NMEA 0183, but you'll be doing that anyway. My B&G plotter does that job on my boat and, neatly, sends the datastream to my boat computer via hardwired Ethernet connection, the same one I communicate with the radar over.

[Franziska]

@Dockhead & Hakan, thanks for your thorough reply.

May I sum up what I make of it as conclusion for our situation? Perhaps you can correct me if you think that I misunderstood something.

We are on a tight budget when it comes to finance and power availability.
I understood that pulse would be better for tracking squalls, but as they consume much more power I guess we will need to go 3G or 4G. Budgetwise I lean towards 3D than. Is weather tracking much different between 3G or 4G?

We use exclusivly OpenCPN and SailGrib as chart software and have no plotter. So I prefer a solution where I can overlay the radar over the charts in openCPN. So it sounds that we can not use the NAVICO as it is not compatible with OpenCPN if I understand you right.
As I am not a developer I am not sure how I can help getting it compatible with O. I do not mind a cable going to the PC.

So it points me towards a Furuno 3G (as long as its PC and OpenCPN compatible). Correct?

Just saw Hakans info regarding the cable. Thanks. That's great.

We have an 0183 network attached to a NMEA-Multiplexer MiniPlex-3USB-N2K . So i guess we can feed compass data into the network via the N2K connector.

Sorry to bug you again ;-)

Originally Posted by Dockhead

Pulse radar is better at tracking squalls, than CW radar like 3G and 4G.

If you intend to use your radar with a computer, and not with your plotter, then by all means you will want one of the Furuno wifi radars. You can't use it with OpenCPN so far (but maybe you would be the volunteer who helps our wizards develop that plugin), but you can use it with its own application. I have been using 4G radar for 7 years now; it is very good at some things, but not so good at others. Squall tracking is somewhat acceptable, but far worse than a good pulse radar. MARPA (at least on my boat) is utterly useless; Furuno on the other hand has real ARPA which by all reports works brilliantly well.

The best thing about the 4G radar, and it's not a minor thing, is that the signal processing is so good, that the guard zones are almost flawless, at least in reasonable sea conditions. I don't know whether the Furuno radars are as good in this, but the Navico 4G guard zones are absolutely brilliant, which is a huge enhancement to watchkeeping. You might go days without a false alarm, and only once in 7 years did any vessel slip through unalarmed, to my knowledge. The other good thing about these radars is the absence of the main bang, so very good imaging at very close ranges, which is extremely useful in, for example, a fog. You can easily see channel markers even less than a boat length away, which is really useful when you need to navigate in a channel in a heavy fog.

But for squalls, or MARPA -- not the best tool. The bearing discrimination is fairly poor in general, probably because the antenna is so small. These radars rely on very intense and sophisticated signal processing; the quality of the raw data is limited by the length of the antenna.

When it comes time to replace this radar, I will probably go with Furuno.

As to wiring of the Navico radars (your other question) -- there is a single ethernet cable, which also supplies the unit with power. It's pretty easy to connect, but the cable is somewhat fat, so not easy to pull in some cases. On my boat, I think quite impossible without taking the mast down.


This cable connects to an interface box inside the boat, which has a connection to the N2K network in order to get compass data into the radar. This box is in turn connected to your plotters with an ordinary ethernet cable just with the proprietary yellow Navico connectors. You can connect the interface box directly to a computer without any connection to a plotter if you desire. The OpenCPN plugin gives you a full set of controls for the radar. You just need either an adapter cable (what I have), or just whack off the proprietary connector off one end of the supplied cable, and crimp on an RJ-45 connector, and Bob's your uncle.

[Bill O]

Originally Posted by Dockhead

Why wouldn't it? HDG is ordinary network data like anything else. The Furuno compass gives normal N2K PGN's like any other compass. Of course to get ANY N2K data into O you need to convert to NMEA 0183, but you'll be doing that anyway. My B&G plotter does that job on my boat and, neatly, sends the datastream to my boat computer via hardwired Ethernet connection, the same one I communicate with the radar over.

I really dislike "assuming" something works and was hoping for confirmation from someone else installed and was using it w/ocpn.

It more for curiosity question and hope our current gps (or the auto backup unit) works for the MARPA to work well.

[Hakan]

Originally Posted by Dockhead

I don't know if you've seen the new Furuno sat compass, but it is a breakthrough -- for under $1000 in the U.S. I'm buying it for my boat as a Christmas present

If you're talking about the SCX-21 it's very fine. I've installed a few in other boats.
A very good present!

So maybe you are using MARPA (and how do yo have ARPA?) computed elsewhere, than in the radar itself?

I'm using plugin radar_pi! Sorry, I thought that was what we're talking about.
The MARPA is a manually initiated target and the ARPA is from the guard zone. In my picture using the Emulator at home.

[Bill O]

Originally Posted by Franziska

May I sum up what I make of it as conclusion for our situation? Perhaps you can correct me if you think that I misunderstood something.

We are on a tight budget when it comes to finance and power availability.
I understood that pulse would be better for tracking squalls, but as they consume much more power I guess we will need to go 3G or 4G. Budgetwise I lean towards 3D than. Is weather tracking much different between 3G or 4G?

We use exclusivly OpenCPN and SailGrib as chart software and have no plotter. So I prefer a solution where I can overlay the radar over the charts in openCPN. So it sounds that we can not use the NAVICO as it is not compatible with OpenCPN if I understand you right.
As I am not a developer I am not sure how I can help getting it compatible with O. I do not mind a cable going to the PC.

So it points me towards a Furuno 3G (as long as its PC and OpenCPN compatible). Correct?

Regarding the cable you write its a thick cable which is a network cable with power supply. Guess that is proprietary, no?
So it seems not an option to plug a standart ethernet cable into the radome?
That would have been much more thin and easier to route, I could add a separate shielded power cable, more easily routed as well as its flexible and thin.

I am asking this, as we will rewire the arch but have not settled for a radar yet, but we have ethernet cable and shielded powercable which we could place already into the arch. Guess that does not make sense if the radars need propriatary cables.

We have an 0183 network attached to a NMEA-Multiplexer MiniPlex-3USB-N2K . So i guess we can feed compass data into the network via the N2K connector.

Sorry to bug you again ;-)

I don't believe a Furuno radar is supported by the o radar plugin. A Navico 3G or 4G is supported though.
While the Nav. 3/4G are on the less expensive side now, some of the complaints were they didn't show rain well enough. This is why we purchased a Navico halo radar. It is more expensive, but it is very frugal for power consumption, show rain better and is a straight ether net plug in (worked right out of the box). No reconfiguration of the RJ45 is needed for the halo, while the 3/4G needs the RJ45 to be rewired (check w/current radar plugin manual).

[Dockhead]

Originally Posted by Hakan

If you're talking about the SCX-21 it's very fine. I've installed a few in other boats.
A very good present!

I am. If you could share your experience with it, I'm sure it would be extremely interesting to many on here.

Originally Posted by Hakan

I'm using plugin radar_pi! Sorry, I thought that was what we're talking about.
The MARPA is a manually initiated target and the ARPA is from the guard zone. In my picture using the Emulator at home.

That was clear, what is not clear, maybe as a result of my ignorance, is where the computations for MARPA are done -- does the plugin do the MARPA computations in your computer? Does it work better than the Navico done ones? And you are even able to do ARPA? Maybe I haven't played with the plugin enough. Sorry for my ignorance.

[SamH]

Originally Posted by Bill O

Does the Furuno sat compass work w/ocpn? There was some discussion w/it on CF earlier this year, but never saw confirmation it interfaced well.

Yes, the scx-20 works like a charm. It is also extremely accurate.
I receive data from N2K with a NGT-1 into SignalK, and then to OPN.

I also removed the Raymarine flux compass, and control the AP(SPX-30) from OPN over 0183 to a YachtDevices YDNR which translates to N2K.
My old 6001 is connected to the YDNR, which translates ST into N2K. The AP itself has no Seatalk or 0183, only N2K.

[Hakan]

Originally Posted by Dockhead

Why wouldn't it? HDG is ordinary network data like anything else. The Furuno compass gives normal N2K PGN's like any other compass. Of course to get ANY N2K data into O you need to convert to NMEA 0183, but you'll be doing that anyway. My B&G plotter does that job on my boat and, neatly, sends the datastream to my boat computer via hardwired Ethernet connection, the same one I communicate with the radar over.

And if you give the Navico radar scanner a N2K compass via the RI10/11 interface you'll so to say have a N2K->NMEA0183 converter by radar_pi. You can have the plugin to transfer the HDT from the radar scanner to radar_pi and further to OpenCPN multiplexer.
See picture:

[Dockhead]

Originally Posted by Hakan

And if you give the Navico radar scanner a N2K compass via the RI10/11 interface you'll so to say have a N2K->NMEA0183 converter by radar_pi. You can have the plugin to transfer the HDT from the radar scanner to radar_pi and further to OpenCPN multiplexer.
See picture:

That's cool, but I think most of us don't have any problem getting network data into O. My B&G plotter converts almost all of the N2K PGN's into 0183 sentences and sends the datastream out over the Ethernet network, which is how I connect my radar to the the boat computer and O.


What I don't know (asked in a different thread) is whether there is any way to get the lateral SOG (or Nautical Leeway from the DX900i) into O, or use this data.

[Hakan]

Originally Posted by Franziska

@Dockhead & Hakan, thanks for your thorough reply.

May I sum up what I make of it as conclusion for our situation? Perhaps you can correct me if you think that I misunderstood something.
.....
So it sounds that we can not use the NAVICO as it is not compatible with OpenCPN if I understand you right.

So it points me towards a Furuno 3G (as long as its PC and OpenCPN compatible). Correct?

No you've got it to a mix.
All Navico broadband types, (BR24) 3G, 4G and Halo, are supported by radar_pi and OCPN.
The 3G is then a Navico and not a Furuno and no Furuno is supported by radar_pi.
Read more here about radar_pi and supported types: https://github.com/opencpn-radar-pi/radar_pi/wiki

There are also advises about connections.
Håkan

[Bill O]

Originally Posted by SamH

Yes, the scx-20 works like a charm. It is also extremely accurate.
I receive data from N2K with a NGT-1 into SignalK, and then to OPN.

Thank you for the confirmation.