Which radar will perform best with Opencpn?

[Douwe Fokkema]

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.

Are you meaning here the build-in MARPA that is available through a Navico plotter, or MARPA and ARPA availble in radar_pi on OpenCPN ?

Douwe

[Dockhead]

Originally Posted by Douwe Fokkema

Are you meaning here the build-in MARPA that is available through a Navico plotter, or MARPA and ARPA availble in radar_pi on OpenCPN ?

Douwe

I meant the built-in MARPA displayed in the plotter.


Now that I know that radar_pi does its own MARPA, I am dying to try it out. I never played with it, although I've been using the plugin for a while, because MARPA is so useless on my plotters that I don't even think about MARPA. So my process is to do a paper plot, or simply set EBL and VRM on the target.

[Douwe Fokkema]

Originally Posted by Dockhead

I meant the built-in MARPA displayed in the plotter.

Now that I know that radar_pi does its own MARPA, I am dying to try it out. I never played with it, although I've been using the plugin for a while, because MARPA is so useless on my plotters that I don't even think about MARPA. So my process is to do a paper plot, or simply set EBL and VRM on the target.

That is exactly the reason why we added MARPA and ARPA to the radar plugin. For me ARPA is the successor of the classical guard zone alarm, which will wake unnecessary you on incidentally detected waves and ships on harmless courses.

Douwe

[Dockhead]

Originally Posted by Douwe Fokkema

That is exactly the reason why we added MARPA and ARPA to the radar plugin. For me ARPA is the successor of the classical guard zone alarm, which will wake unnecessary you on incidentally detected waves and ships on harmless courses.

Douwe

I can't wait to try it out.

But I wouldn't switch off the guard zones and rely on ARPA. I want to be alerted anytime anything gets within the set distance.

And if MARPA is useless on the Navico plotters, the guard zones are the opposite -- astonishingly good. Almost 0 false alarms, if the sea state is reasonable. The most useful enhancement to watchkeeping I know of.

[Hakan]

Originally Posted by Dockhead

.....
But I wouldn't switch off the guard zones and rely on ARPA. I want to be alerted anytime anything gets within the set distance.
....

Why would you? Pls have a look at the radar control: Guard zones. You can have both ARPA and Alarm set for one zone. And/or also one zone with only ARPA and the other with Alarms using different areas.

[Dockhead]

Originally Posted by Hakan

Why would you? Pls have a look at the radar control: Guard zones. You can have both ARPA and Alarm set for one zone. And/or also one zone with only ARPA and the other with Alarms using different areas.

Well, Douwe suggested ARPA INSTEAD of guard zone -- on the basis that guard zone might "wake you unecessarily". So obviously he has in mind switching off the guard zone alarm. I think this is dangerous (we won't even get to sleeping with no human on watch) if he means switching them all off.



ARPA is slightly useful -- might save a bit of time in a hairy situation with a lot of different targets at once. But I don't think it's a good idea to give up being alerted to proximate objects, even if it does not immediately appear that there is a collision course. YMMV, but I, for one, ALWAYS run my radar and guard zone alarms offshore, even in good visibility, even though practice on my boat is to NEVER leave the boat without an active on-deck watch.

[Douwe Fokkema]

Originally Posted by Dockhead

Well, Douwe suggested ARPA INSTEAD of guard zone -- on the basis that guard zone might "wake you unecessarily". So obviously he has in mind switching off the guard zone alarm. I think this is dangerous (we won't even get to sleeping with no human on watch) if he means switching them all off.

Don't take my remarks that black and white. I use ARPA normally for a larger ring guard zone. This will give early warning for dangerous targets. On top of that I like a small distance guard zone in which I switch Alarm on to be warned for anything getting really close.

And remind, for a guard zone there are two options, ARPA or Alarm (or both)

Douwe

[Dockhead]

Originally Posted by Douwe Fokkema

Don't take my remarks that black and white. I use ARPA normally for a larger ring guard zone. This will give early warning for dangerous targets. On top of that I like a small distance guard zone in which I switch Alarm on to be warned for anything getting really close.

And remind, for a guard zone there are two options, ARPA or Alarm (or both)

Douwe

OK, cool


That sounds like good practice.

[Douwe Fokkema]

And if you have a dual range radar like a 4G, you use a different radar window with different ranges set, for each of the guard zones. This will give you the best target resolution. Also you can adjust sea clutter exactly on the edge for each of the ranges.
Douwe

[Bill O]

Originally Posted by Dockhead

The whole purpose of NMEA2000 certification -- an expensive process -- is to GUARANTEE compatibility. Any NMEA2000 certified compass MUST be compatible with any other certified NMEA2000 device, including whatever device you use to convert the PNG to the 0183 sentence "HDG", which is what O understands and uses.

So it's not an assumption. You are relying on the certification, and you are paying for this reliance when you buy an NMEA2000 certified device.

Not trying to beat a dead horse here, but a NMEA 2000 device will not be a direct plug/play into OCPN and agree one needs hardware to convert it to 0183 for OCPN.


Really just wanted to make it abundantly clear that depending on the set up, one may be need hardware and some setting reconfiguration to make the NMEA 2000 work.

While it's nice to have the latest/greatest, there may be lots of hoops to jump thru to get them to work correctly. Once you get the settings done correctly it's all good then, but we are finding this out (again). The newer plotter set up w/a pi4 to talk to everyone properly (AP computer, nav. station, cockpit computer) is taking a bit of time to configure.
With that said, the radar pi w/the halo was the easy part and really was plug/play. Again would recommend the halo for ease of set up.

[Dockhead]

Originally Posted by Bill O

Not trying to beat a dead horse here, but a NMEA 2000 device will not be a direct plug/play into OCPN and agree one needs hardware to convert it to 0183 for OCPN.

Really just wanted to make it abundantly clear that depending on the set up, one may be need hardware and some setting reconfiguration to make the NMEA 2000 work. . .

Well, I specifically mentioned that.

But this is not rocket science. And the guarantee of compatibility is preserved provided the convertor whatever it is, is also NMEA2000 certified.

An incomplete list of ways to do this:

1. Convert via your plotter, variant 1. Connect the 0183 talker port through a USB adapter and connect to your boat computer.

2. Convert via your plotter, variant 2. Connect the plotter's ethernet port to your boat computer ethernet port.

3. Convert via your plotter, variant 3. Connect the boat computer to the network via Wifi and GoFree or similar.

4. Use a freestanding N2K to 0183 converter like the Actisense NGW (or one of the many other ones).

5. Use a WiFi server with built-in convertor; many types available (YachtDevices; Actisense; etc.).

6. Use a SignalK server.

I personally like ethernet best. I think it's the most robust connection. In my case, I get radar data over the same ethernet connection.


I like this device very much:





Terrific way to connect a boat computer to a boat network, in case your plotter doesn't do this (or if you don't have a plotter, or if you don't want to depend on your plotter for this).

[Tupaia]

Originally Posted by Bill O

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).

The NAV 3G/4G does not need to be re-wired the RJ45 plugs straight into the PC no configuration required.


The Halo and 3G/4G models use slightly different tech with Halo using pulse compression giving very slightly better squall definition. Neither are as good at this as a full "old fashioned" pulse radar.


Although both 3G/4G and Halo 20 have running consumption of 18-20W the Hal has roughly twice the standby consumption 6.5W vs 2.9W albeit that both are tiny.

[Bill O]

Originally Posted by Tupaia

The NAV 3G/4G does not need to be re-wired the RJ45 plugs straight into the PC no configuration required.


The Halo and 3G/4G models use slightly different tech with Halo using pulse compression giving very slightly better squall definition. Neither are as good at this as a full "old fashioned" pulse radar.


Although both 3G/4G and Halo 20 have running consumption of 18-20W the Hal has roughly twice the standby consumption 6.5W vs 2.9W albeit that both are tiny.

Not to quibble, but the ocpn manual for the Navico radar still says in certain installations the RJ45 needs to be reconfigured. https://opencpn.org/wiki/dokuwiki/do...e_installation
It's not that big of a deal but you possibly may need to purchase a special crimper.


Bottom line, need to read the manual to check everything you may need to do to get it to work properly.

[Bill O]

Originally Posted by Dockhead

Well, I specifically mentioned that.

But this is not rocket science. And the guarantee of compatibility is preserved provided the convertor whatever it is, is also NMEA2000 certified.

An incomplete list of ways to do this:

1. Convert via your plotter, variant 1. Connect the 0183 talker port through a USB adapter and connect to your boat computer.

2. Convert via your plotter, variant 2. Connect the plotter's ethernet port to your boat computer ethernet port.

3. Convert via your plotter, variant 3. Connect the boat computer to the network via Wifi and GoFree or similar.

4. Use a freestanding N2K to 0183 converter like the Actisense NGW (or one of the many other ones).

5. Use a WiFi server with built-in convertor; many types available (YachtDevices; Actisense; etc.).

6. Use a SignalK server.


I personally like ethernet best. I think it's the most robust connection. In my case, I get radar data over the same ethernet connection.

I wasn't disagreeing w/you, just wanted to make it clear for everyone that you possibly need the extra hardware and then configuring (e.g. signalk) get them to work. Yes there are many examples of the hardware in the manual link provided previously.This can be a pain at times and shouldn't be matter of factly glossed over as easy (full disclosure).
We do our own work and can compile from source, so we know it can be frustrating at times.

[merrimac]

Originally Posted by Bill O

Not to quibble, but the ocpn manual for the Navico radar still says in certain installations the RJ45 needs to be reconfigured. https://opencpn.org/wiki/dokuwiki/do...e_installation
It's not that big of a deal but you possibly may need to purchase a special crimper.


Bottom line, need to read the manual to check everything you may need to do to get it to work properly.

Contra quibble, you are referring to the OpenCPN wiki which is not accessible to us plugin writers and are outdated compared to the plugin wiki, see https://github.com/opencpn-radar-pi/...lation-(Navico)


If you call crimping on a RJ45 to save a few bucks "reconfiguring" then maybe you shouldn't be doing this at all. Or you can read the proper manual page and buy a Navico RJ45 to Yellow converter cable.