AIS stops sending - good ideas appreciated

[lasmaruezas]

Hi,

I've been on the mailling list for a year or so, but this is my first post.

Onboard my 2006 Bavaria 46 Cruiser I've installed a Camino 108 AIS Class B transponder. This transponder is connected to an AMEC GPS antenna for AIS as well as a Pacific VHF antenna. The AIS is also connected to my NMEA 2000 bus as well as power.

When I plug this setup to a computer using the software which came by the Camino, all indicators are good: Power is on, no error codes, MMSI is valid, external power ok, GPS position is fixed, the AIS has indeed received a position report and the AIS has transmitted a position report. Messages are received as well as transpitted on both channel A and B.

At this point, I also see my vessel on Marinetraffic. I now that this website in itself is not a true witness to whether your AIS transmits or not, but in this case it is relevant.

Having transitted and being received on marinetraffic, however, after a short while it stops transmitting. This happens regardless of whether I disconnect the computer or just let it be plugged in.

I should add that I so far have used the app BoatBeacon rather successfully, but this only works whenever I've got a mobile signal.

The past weeks I've crossed the North Sea, the Caledonian Canal in Scotland, and at time of writing I'm in harbor at the Outer Hebrides. On our way back to Norway, I would have loved for the AIS to work.

All this being said, I would very much appreciate good advice from you!

[svmobert]

How do you confirm that it has stopped transmitting? Maybe it IS transmitting and whatever tool you are using to check it is not updating or receiving it.

[lasmaruezas]

Thanks for replying.

Originally Posted by Sea-TechSystems

How do you confirm that it has stopped transmitting? Maybe it IS transmitting and whatever tool you are using to check it is not updating or receiving it.

That could have been the case, but no. Today I crossed the North Sea from Shetland to Norway and communicated with a supply ship at one of the oil rigs. He did not see me.

I haven’t a clue as to what to do except trying out some different software.

[svmobert]

Originally Posted by lasmaruezas

Thanks for replying.



That could have been the case, but no. Today I crossed the North Sea from Shetland to Norway and communicated with a supply ship at one of the oil rigs. He did not see me.

I haven’t a clue as to what to do except trying out some different software.

Have you contacted AMEC support to ask them about it? That’s what manufacturer tech support is for and probably a better bet than a crusing forum, not that your post here isn't a good idea, just suggesting that the manufacturer may actually be helpful.

[PhilipLyra]

I have a similar problem with CAMEC 108S. First unit failed after 1.5 years, was replaced. Now vailure after 3 month.
Did you get any solution?
Philip Beekman, SV Lyra

[barnakiel]

Doh.


Never knew these had problems. But apparently they do.


Can you pls update us when you get a response from the company?


barnakiel

[wingssail]

You have a computer application for the device. Does it indicate you are still transmitting? (and what about indicator lights, does it have any on the unit?)

If not: (Meaning the unit knows it is not transmitting)
Then what do the error messages say? Or the log. Or, open the NMEA file with either OpenCPN or something like hyper terminal, and look at the output messages, It might give a reason. If no error messages or explanation in the NMEA output, then possibly the unit has failed. Talk to the manf.

If Yes: (it still thinks it is transmitting):
Then you need to ask another cruiser who has AIS to help you conduct a systematic test, not just a passing ship.

If your test results indicate that you are not transmitting when the unit says it is, then perhaps the unit is broken.

[smac999]

high swr error will stop it from transmitting.

or loss of gps.

both of those should be seen on the computer program though. and should cause a different light on the unit.

[PhilipLyra]

All indicator lights are normal; Report indicates no fault (also no fault on swr); non-transmission confirmed by several sources including coast guard. At this time the only odd signal is, that when I transmit from my VHF radio, sometimes the TX VHF light comes on and sometimes not, but Radio transmission is excellent.
I have contacted Alltekmarine and sent them detailed additional information as requested by them. At this stage I am waiting for their reaction.
I have checked the contents of the NMEA !AIVDO messages to my computer, and those are correct, including position, ship size etc.

[barnakiel]

Testing onboard will be inconclusive.


Make sure the vhf line is good and swr is within range. Bad antena or bad cable or connenctions (at each end) may be the cause of non-transmit.



Make sure the diode is ON.


Ask a fellow sailor to confirm they lost you while the diode is ON.


At this point dismount the unit and ask the manufacturer to test it.


(testing of the nmea chain is fine but not explanatory, if I recall right: three sentences: gps line, own ship line, alien ship line(s))



b.

[PhilipLyra]

@Barnakiel; thank you for your comments. 108S has a special led for SWR "Warning Orange, steady The red LED illuminates when antenna VSWR is over 3:1
by VHF transmission at 25W."
In my case that led does not light up, so I should trust that SWR is not the problem.

[s/v Jedi]

The computer software shows numberof transmissions for each channel. Does that counter stop?

Also, it has an error log. What messages are there?

[barnakiel]

Originally Posted by PhilipLyra

@Barnakiel; thank you for your comments. 108S has a special led for SWR "Warning Orange, steady The red LED illuminates when antenna VSWR is over 3:1
by VHF transmission at 25W."
In my case that led does not light up, so I should trust that SWR is not the problem.

OK. If it is based on SWR and does not warn, it is assumed innocent.


b.

[PhilipLyra]

@s/v Jedi, thank you for suggestion.
I am using Ais Configuration tool V2.0.6. as supplied by Camec.
Counters for transmission count up. I cannot find any error log on this tool.
Is there another tool for this transponder?

[Brian.D]

lasmaruezas, when trouble shooting a problem start at one end and work towards the other end. And... there are the 3P's to keep in mind. They are Power, Parameters, and Parts.

First look at the antenna. It will receive a signal unless the stainless steel whip is missing. Even if the whip is broken off it still might receive. But if the antenna is not working correctly it could prevent the transmitter from sending a strong enough signal for the distant end to hear you. Although the antenna is probably tuned for AIS, it is still in the Marine Band so you might try putting your VHF radio on and see if anyone at a distance can hear you. At a distance being near or over the horizon.

Now inspect the antenna cable. Again, with a strong enough signal your receiver might still work if the cable is damaged. However, transmissions could be attenuated to the point of not even reaching the antenna.

This leads to an unusable or high SWR. This will kill a radio to the point it will not transmit no matter what. The SWR should be visible on your software or might be visible on the radio's display. You will need test equipment to see if the radio is even producing any RF energy.

Power is also something to think about. Power being the DC from the battery, not the amount of wattage the radio produces. If for some reason your DC power is being reduced on transmit, very little signal will get to the antenna. Corrosion in the cable or connectors could cause your AIS radio to still work, but not very efficiently.

Check, double check, triple check your parameters. Even one parameter could make the radio useless. I don't know if there is a difference between US and EU AIS, but if there is a parameter for that, check it.

Lastly, parts, it could very well just be a dead transmitter. Like I said before, you will need some test equipment to check. If you see other cruisers ask if they are hams and if they have a dummy load and watt meter aboard. This will tell you if your are indeed transmitting.

Good luck and all this is JMHO.