AIS transceivers, Comar

[jfm]

I'm having to buy a whole boat electronic set, from scratch. Was thinking of getting a class B AIS transciever, to assist me in being seen by commercial ships on night passages. Hurric mentioned this on another thred, and I had a few questions which I'd be grateful for any comment on from Hurric or anyone who knows. I'm putting all this in new thread to keep the forum tidy and not drift the other fred.

1. hurric has the Comar and says its good. It's same price as Raymairne receive only unit, £500

2. Hurric did you fit a dedicated VHF antenna for it, or did you buy the Comar splitter to use the boat's VHF antenna? If you used the splitter, is it OK? I'd like to use the splitter, for simpler installation.

2. I think (correct me if I'm wrong) the Comar gets its position data from its own GPS engine. It then talks its position out to the Raymarine gear via NMEA0183 in the RMC sentence. That's handy, cos Raymarine ignores the RMC sentence coming in on NMEA0183, if Raymarine already has GPS data via Seatalk 1. But if, say, the Raymarine GPS mushroom fails (which has happened to me) you can just unplug the mushroom cable from the seatalk 1 network and hey presto Raymarine will start reading the RMC sentence from Comar. Hence, you have a GPS back up. Good stuff. Have I got this right?

3. Did you manage to panel mount the Comar? Hurric. I couldn't have it trunnion mounted like n their website. It seems to have a flange, so can be dropped into an auxilliary panel (not the main dash, it's not pretty enough)?

4. Another AIS gizmo for £500 is this one but it looks ugly and you cant hide it away cos you need to get to the buttons. Urgh.

5. I might program the unit with a slightly different boat name, so if someone calls me I know they are AIS-ing me. On Hurric's boat I would make it Jennifer Wren, frexample. Or maybe that's daft. I'll think about it

Any other comments on AIS transceivers as opposed to receivers would be very welcome, thanks

 

[gavina]

I have to state an interest as we sell and fit AIS units. In our opinion the Comar units are excellent and much of their business is in the commercial field.

We find that splitters work well and use one on our own boat however if you have a motor boat it might be quite easy and cheaper to fit a separate antenna.

You are correct in that the CSB200 gets its position from its own GPS unit and your assumption that this could be used as a backup for the Raymarine unit seems correct although we have not tried this ourselves.

If you have other devices connected to the NMEA input/output on the Raymarine unit you might need to use a multiplexer as the Comar CSB200 in common with most other AIS units operates at 38400 baud. If you are using Raymarine ancillary equipment connected via Seatalk this is no problem unless you have a smart heading sensor as this has an NMEA output.

The AIS unit has no switches and can be mounted out of the way – there are some indicator lights but these are only really required for diagnostic purposes. A separately mounted switch can be used to turn the AIS TX on and off and we supply on one with a connecting lead for this purpose.

 

[gjgm]

I too was looking.. does the Digiyacht one need access to buttons? Or is that just to set it up?
I d rather thought you install these things , and then thats it (unless it goes wrong)...
Tried looking on USA websites.. they dont seem very available there... just thought they might be half the price. Mind you, not alot of choice in Europe either/anyway.

 

[nimbusgb]

Fitted a Comar 200 Transceiver recently. Went in and worked straight off the bat. Talked to the e-80 immediately too. Forget about panel mounting the unit ( big dissapointment, Comar are you listening? ). It has the same sized flange on both ends so you would have to either strip it to install it ( warranty bye bye ) or make up a split surround trim ( far too involved ) believe me I would have done it if I could. The more pretty flashing lights on my panel the better AFAIAC /forums/images/graemlins/smile.gif. In the end I mounted mine in a IP65 enclosure along with some other bits an pieces ( multiplexer, autopilot engine, navtext, FLS main box ) and wired the AIS tx enable switch where I could get to it. I used a separate arch mounted antenna to simplify matters, it also provides a good alternative to the main antenna that can be used by a handheld or the main vhf if things go wrong at the top of the mast.

 

[gavina]

I'll talk to Comar about the panel mounting - but to be fair their unit is compact and robust.

 

[jfm]

Thanks Gavina, great info.

Yes, I would need multiplexer becuase I do feed Smart Heading into the Raymarine via NMEA0183 (actually, as i have two Ray E-series screens, I think I can put the smart heading into one of them and the AIS into another, and then they will self-multiplex so to speak. (?) But I'd have to have them both turned on and prefer not to have to

Nimbus is dead right about the panel mounting. However, you have offered the perfect solution with the remote switch for the TX function, which I can lead back to a Carling switch on my dash so it will look OEM. Perfect, thanks!

Right, I'm all decided. I've just been onto your website to buy all this stuff but I didn't find the shop very easy. I couldn't find a "add to basket" button for the Comar. I could find it for the multiplexer. Can you help me buy this stuff please? I can PM you my Cr card and address if that helps. I need please

Comar AIS
GPS antenna for it
the remote on/off TX switch lead (or do I just connect a wire to some terminals? I dont need a switch as I'll use a Carling)
VHF easysplitter gizmo and leads,
multiplexer so I can feed the NMEA into one Raymarine E

Thanks

 

[Hurricane]

[ QUOTE ]
Hurric did you fit a dedicated VHF antenna for it,

[/ QUOTE ]
I have two whips on the Princess - makes it look a lot more balanced. So one is for the VHF and the other for the AIS - origionally, the spare one went to the FM radio but we made provision elsewhere for this. So no splitter.

[ QUOTE ]
I think (correct me if I'm wrong) the Comar gets its position data from its own GPS engine.

[/ QUOTE ]
I believe that this is vital for any system transmitting AIS - not only for its position but more importantly to get accurate GPS timing information so that it can synchronise its time slots etc.
Anyway, there is a 9 way connector on the Comar that outputs both NMEA to the plotter and a separate serial to a PC. The PC connection is used to set it up (to add your boat name / MMSI etc). The NMEA output goes to one of my Raymarine GPMs - This is where the G series scores anothe small hit - there are two NMEA 0813 interfaces on each of the G Series processors (GPMs). So I didnt need to multiplex it.

As for backup, I connect the Comar's PC interface to my dedicated ships PC. Thus, if my Raymarine mushroom should fail, I would be able to consider the whole G Series as failed because the Comar feeds th PC which is running my favourite Memory-Map software completely in parallel to the Raymarine kit. To me, the PC installation has become a very important component to the whole system. It integrates absolutely everything. However, I've designed it so that the PC doesnt "take over" from the dedicated ships systems and that if the PC should "go down" then all the other systems will continue to run independantly. I'm sure that this is the way forward for the future.
For example plotting routes can be time consuming. Using Memory-Map, I simply click click a mouse to create and upload a route to the Raymarine systems. The route has then been planned on raster charts and can be double checked on the Navionics vector charts as well. Also, once underway, the two systems continue to plot independantly so that you can see any mistakes immediatly. So thats my attitude to backup.
The "talking log" comes out of this design for free because there's a spare feed from the Comar which carries all the NMEA GPS plotting information - and a simple Windows app translates this logging data.

Panel mounting - as others have said there is no need to panel mount it - all the warning lights etc arent important anyway. In my case, if I DO need to see them, they are repeated in the Comar software which runs on the PC - yep there's that PC again. Incidentally, the Comar has quite a good display of all the AIS targets that are being received.

The Comar is the little box at the top left here - behind the seats in the dinette.

As far as a different boats name is concerned - not sure thats actually necessary. I think it takes a while for an AIS engine to receive additional infor from a target - maybe Rickp can explain why - but when I've been monitoring AIS, you get the important info first (MMSI, SOG, COG etc) and other stuff like the ships name etc later. Anyway, we've only had the situation once when the Spanish CG wanted to know who we were. They simply dialled our MMSI into their DSC VHF and called us electronically. Which completely threw us!!!

One last point on the PC
You need a PC (or laptop) to set up loads of things these days - another one is the Sat domes - so why not spend a bit of time and get a reliable PC perminantly installed on board. In fact I built my own into a small box that travels with me on the aeroplane - I can then install software or data at home and simply plug it in when I get to the boat.

Oh yes - mouse control - have you heard of an "Air Mouse" - this is a wireless mouse that has Nintendo Wii type gyros built in. You simply wave it around in the air as a mouse pointer - no need for a flat surface. It also works 10 metres away from the receiver so I can use it anywhere inside the boat as well as on the flybridge - including at my little desk in the main cabin. It also comes with a wireless keyboard which also has a long range. In fact they have versions of Air Mouses and Keyboards that work at 30 metres. If anyone's interested I'll post a link to them.

 

[jfm]

Thanks for all that fantastic info Mike. Great installation you've got there (understatement!). I'd be out of my depth (which isn't very deep) with some of the interfacing you describe . I have ordered the Comar and accessories from Gavina, arrives this week