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7/18/2019 12:22 am  #1

AIS impact on B&G H5000 and Expedition

This is not so much a question as a discussion starter.  A couple of days back I walked an AIS MOB beacon down the marina and set it off in order to see what happened.  I was a bit surprised, and now trying to figure out the best MOB management process.  There are 3 images in the below link.
https://imgur.com/a/BLOMY98.  AIS MOB.PNG shows Expedition after the AIS is activated.  First the MOB Active rectangle appears down the bottom, then about 3 minutes later the red crossed icon appears.  AIS MOB2.PNG shows what happens when the AIS moves, a "breadcrumb trail" at one minute intervals is formed.  Expedition AIS.PNG shows what happens in Expedition.  An Expedition MOB is NOT created and your current Mark Range and Mark Bearing are not affected; rather a new Marks (MOB) folder is created. Additionally, an MOB in B&G is NOT triggered by the AIS; the B&G AIS screen (on a B&G graphic display) displays the red crossed image among other AIS targets.
I'm now thinking through the ramifications of all this.  Pressing the B&G MOB button will bring the MOB screen onto the B&G GD in place of the AIS image and will put an MOB into Expedition which will replace Range Mark and Bearing .... which may not be the same as the AIS location, and can't track drift of the AIS target.
The forum is open!  Incidentally, if you do this on a marina, have your VHF on and warn boats around you.  I had 3 queries from people with AIS alarms on their radios.


7/22/2019 10:46 am  #2

Re: AIS impact on B&G H5000 and Expedition

i have used the test mode in the MOB 1 to see what it looked like on the chart plotter and on Expedition - were you using the test mode.., or did you really activate it?

what i am really wondering about is the alarm on other boats - was it a DSC alarm?

in the USA.., the DSC call from the MOB 1 only goes to the boat you fell off of..., something about the FCC (Federal Communications Commission) licensing... 

in order for it to do that, you have to program in the MMSI of the boat you are on.., and if you use it on different boats, you have to reprogram it when you change boats. Otherwise, the DSC call won't go to anyone.., except the original boat if they are within VHF range.

I guess I understood that for a MOB 1 purchased in Europe the DSC call would go to all ships within range, and it sounds like Australia  is the same.

Anyway, I will try a more complete experiment next time - leave it on for a while and move it.., and see what i get.


7/22/2019 12:55 pm  #3

Re: AIS impact on B&G H5000 and Expedition

Yes to generally-heard DSC alarm, and yes to my setting it off in reality, not in test.  As I understand it - and you have outlined - if you program your MMSI in the devices you get an alarm on your VHF.  But I reckon if someone is overboard, the more boats around you that know about it, the better.
I'm still not sure how to manage the interaction between the AIS signal and hitting the MOB button, which will of course replace the AIS on the yacht displays, especially as the AIS signal will move with the swimmer, and the MOB won't.

     Thread Starter

7/22/2019 1:31 pm  #4

Re: AIS impact on B&G H5000 and Expedition

as i understand things.., for a device sold in the USA, the DSC call to the programmed MMSI is the _only_ call that gets made, and there is no possibility of an all ships call

given what you are saying.., wouldn't the best thing be to just navigate to the newest position in expedition?


7/23/2019 12:12 am  #5

Re: AIS impact on B&G H5000 and Expedition

What I'm thinking about is the procedure to best follow when you have MOB available in Expedition and B&Gs (and a B&G GD attached), AND people have these personal AISs.  If someone goes over the side and you press MOB on either Expedition or B&G button fitted, the default on the B&G GD is automatically the MOB screen; I haven't tested, but I don't think you can change pages without cancelling the MOB Have to check that).  However, this means you cannot see the AIS image on the B&G GD.
So, noting that AIS position takes a couple of minutes to appear (and in a TP at speed, that's over 1/2 a mile in distance), do you hit the MOB button, have that appear on the GD, and separately track the AIS position on a tablet repeating Expedition?  And to which location do you head?  The AIS should be more accurate, as it is updated.

     Thread Starter

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