Checking AIS transmissions

[Daydream believer]

I have fitted an AIS transponder & even on my rail mounted aerial I am picking up transmissions 25 miles away.

However, I do not know if I am transmitting OK. I have asked around the marina & from the couple that currently have AIS receivers I get a negative reply.
To avoid pestering them any more can someone tell me how to check my transmissions easily & without specialist equipment. Or is that a no no??. My set up is slightly different to the standard Amiel unit as I have purchased an extra switching unit that cuts out the transmissions & it may be that it is not set up right.

 

[Pinnacle]

Have a look on http://www.marinetraffic.com

You may have to be patient as it does not always quickly pick up new stations.

 

[Andrew G]

+1 for marinetraffic but it will depend if they have a receiver in your vicinity (they provide free receivers to local sites which then transmit the data back to their base via the www). If you can "see" other targets around you, and not yourself, then you have a problem. Don’t forget that if you are not moving you will be transmitting less frequently (say 2min) so patience may be required (or get out of the marina). (I had the same issue and radioed a nearby target and subsequently met the couple who had at the time advised they couldn't see me - only for me to appear after I had logged off the radio). Cheers, Andrew

 

[johnalison]

My boat comes up on SFHDfree but there can be something of a delay before it appears. Not only that, but a photo of my boat can be brought up. Goodness knows where they got that from.

 

[Daydream believer]

. Not only that, but a photo of my boat can be brought up. Goodness knows where they got that from.

The wanted poster outside the local nick!!:ambivalence:

 

[emandvee44]

To upload photos on Marinetraffic.com you need to be a member, but it is free to join. Interestingly, you can then upload photos of any vessel which is currently displaying.Some opportunities for mischievousness? It was actually easier to upload photos than on ybw
Oh, don´t look for us - we are laid up.

Cheers,

Michael.

 

[Javelin]

I set up an AIs on a simrad system the other day on acustomers boat.
Powered up and all hell broke loose with the plotter identifying a "Dangerous vessel" 6' to starboard.
The plotter had found an unidentified AIS contact, however as soon as I entered the MMSI number in the ais settings the rogue boat vanished and things went quiet again.
The simrad Nais400 uses a separate gps for transmitting info whilst the rx out-put uses the plotter gps info which I found a little strange and frankly a pain having to run another antenna.

Anyway regarding your question I was wondering if you could reverse the process and edit the mmsi number to an incorrect one for a few minutes and see whether you'd get a rogue boat on top of you.

The Simrad transponder apparently transmits once every 6 minutes so if you miss the handy little TX light come on you either have to shut down and re-start or wait.
In my case the Marine traffic app I have on my phone picked up the ais transmission within 10 minutes.

 

[Robin]

Have a look on http://www.marinetraffic.com

You may have to be patient as it does not always quickly pick up new stations.

IT doen't pick ours up but Vesselfinder does even on my mobilephone App version, see here. I have the paid for android App at $6.99 (IIRC) and it worked to show us whilst I was still on board checking if the 'AIS silent' switch was left in the 'on' position by mistake. Marine Traffic still has not shown us transmitting, even now some several hours later..

http://www.vesselfinder.com/#

 

[prv]

The simrad Nais400 uses a separate gps for transmitting info whilst the rx out-put uses the plotter gps info which I found a little strange and frankly a pain having to run another antenna.

Apparently this is required by the AIS rules.

Pete

 

[Robin]

Apparently this is required by the AIS rules.

Pete

I wondered about that too as our new Garmin setup has two separate GPS antennae, sitting like a pair of lovebirds together on the rail, one is for AIS only the other feeds the NMEA 2000 system of plotter, radar et al as well as the Standard Horizon DSC VHF(the latter connected by NMEA 0183) whereas number 2 antenna feeds only the AIS transponder it seems

 

[srm]

I was wondering if you could reverse the process and edit the mmsi number to an incorrect one for a few minutes and see whether you'd get a rogue boat on top of you.

Am currently looking for a class B AIS - the manuals I have looked at online all say there is only one go at entering the MMSI number. Suggest that you check your manual carefully before trying anything like this.

 

[Robin]

Am currently looking for a class B AIS - the manuals I have looked at online all say there is only one go at entering the MMSI number. Suggest that you check your manual carefully before trying anything like this.

That is certainly the case with our Garmin one, plus over here they also insist the MMSI data is entered by the professional installing dealer, even West Marine do it before shipping the set out to their customer, even if you order/buy in store. In the software supplied with ours there is a space to put the 'vendor' code in before entering the MMSI by sending the data from a computer via a USB/micro usb to the AIS itself. Thereafter the user can reconnect to add more vessel details (name, draught etc but the MMSI is set in stone or is a factory return for reset. setting the MMSI into a DSC VHF is similarly a once only job, or needs a factory reset, but it does prompt you to treble check the number is correct before pressing the final ''enter' key that sets it in stone..

 

[Daydream believer]

My boat comes up on SFHDfree but there can be something of a delay before it appears. Not only that, but a photo of my boat can be brought up. Goodness knows where they got that from.

Excuse the ignorance - but SFHD free !!! ?

 

[BrianH]

That is certainly the case with our Garmin one, plus over here they also insist the MMSI data is entered by the professional installing dealer, even West Marine do it before shipping the set out to their customer, even if you order/buy in store. In the software supplied with ours there is a space to put the 'vendor' code in before entering the MMSI by sending the data from a computer via a USB/micro usb to the AIS itself. Thereafter the user can reconnect to add more vessel details (name, draught etc but the MMSI is set in stone or is a factory return for reset. setting the MMSI into a DSC VHF is similarly a once only job, or needs a factory reset, but it does prompt you to treble check the number is correct before pressing the final ''enter' key that sets it in stone..

My Amec Camino was supplied with a software utility to enter all the ship's data with, including the MMSI, but with the caveat that the latter is a once-only input - when stored it cannot be overwritten. When entering the data I was ultra cautious and checked and double-checked the MMSI before clicking on 'Enter'.

I could monitor my AIS transmissions with the "NMEA Debug Window" in OpenCPN - accessed through the Options->Connections menu. With the receiver connected via USB the data stream can be stored and analysed by an AIS Parser - I think I used this one: http://www.maritec.co.za/aisvdmvdodecoding.php

 

[BrianH]

I could monitor my AIS transmissions with the "NMEA Debug Window" in OpenCPN - accessed through the Options->Connections menu. With the receiver connected via USB the data stream can be stored and analysed by an AIS Parser - I think I used this one: http://www.maritec.co.za/aisvdmvdodecoding.php

I have just read the OCPN manual with reference to my comment about using the NMEA Debug Window to monitor one's own AIS transmissions. It appears that I was using an earlier version that erroneously displayed own ship signals.

AIS Transponder and Own ship.

OpenCPN 3.2 does not show the own ship (i.e. AIVDO message) neither as an AIS target, nor in the target list. AIVDO is processed only in the main navigation thread.

Earlier releases did show ownship, but this was a bug, simply an illusion.

The earlier presence of AIVDO (ownship) information in the data stream, really only indicated that the transponder was turned on and received GPS signals. The only true way to monitor the output of a transponder, is with a separate AIS receiver.