WAtchmate 650/ Icom MXA5000 AIS problem

[Jim Cate]

G'Day all,

We have developed a perplexing problem with out AIS receiver system. It consists of a Northstar GPS and an ICOM mxa5000 AIS receiver/antenna splitter feeding a WAtchmate 650 display and OPCN on a laptop.

The system worked flawlessly from the first time I fired it up around three years ago. A couple of days ago, I noticed that many of the registered ships were "Xed out" after being logged in. On OPCN, they would show up yellow and as "unidentified" and never be "turned green" with full data.

Specifically, targets appear normally, ie one or more transmissions are received and the ships are "logged in". After that initial contact, no further info is noted, and after the appropriate time the target is marked as lost. Interestingly, a very few targets are updated a few times, with full info being posted and position updated, but even that is hit or miss and not reliable.

I've checked the antennas, and they are working normally. Ships are being detected at normal ranges of 25-50 miles... just not updated after the initial contact. I'm perplexed... and would appreciate any suggestions for troubleshooting. I don't even know whether this indicates a problem in the Icom or the Watchmate.

Thanks for any ideas you may have.

Jim

[Ziggy]

Jim,
From your description, it wasn't clear if you see the same symptoms on the Watchmate and OCPN displays? i.e., do the targets become "lost" on both? If so, the most likely problem is the ICOM AIS receiver.

[Draikhyan]

- A problem in the AIS receiver? Try re-flashing/updating its firmware.
- Wiring problem between receiver and display? Try disconnecting at receiver end.

[Jim Cate]

Originally Posted by Ziggy

Jim,
From your description, it wasn't clear if you see the same symptoms on the Watchmate and OCPN displays? i.e., do the targets become "lost" on both? If so, the most likely problem is the ICOM AIS receiver.

G'Day Ziggy,

Yes, the symptoms are seen in both the Watchmate display and OPCN. The manifestations are different due to presentation differences, but the initial contacts and eventual time-out are the same.

And this does in some respect point at the Icom, but I'm confused by the fact that it gets the initial contact and transmits the data onward successfully, and then fails afterwards... except in the few cases where it does update a time or two.

Thanks for your interest and help.

Jim

[Jim Cate]

Originally Posted by Draikhyan

- A problem in the AIS receiver? Try re-flashing/updating its firmware.
- Wiring problem between receiver and display? Try disconnecting at receiver end.

G'Day Draikhyan,

Thanks for the reply and suggestions. I'm not sure what you mean by "re-flashing" the firmware... does not sound like something one can do on board. And I don't understand why updating the firmware would be required when it was working normally just a day before?

There was the usual very brief "manual" supplied by Icom, and there was no mention of any software master reset sort of action. In fact, there is no interaction required to get it on line... one simply hooks it up to GPS, Watchmate and computer and off it goes, at least for the first three years!

Cheers,

Jim

[colemj]

Originally Posted by Jim Cate

I'm not sure what you mean by "re-flashing" the firmware... does not sound like something one can do on board.

Jim, you need to approach it from behind wearing a raincoat and nothing else, then say to it "hey, you got a minute?", and then when it turns around....

I don't know anything about this unit and am taking a wild stab, but have you tried bypassing the splitter to rule out that as the problem (if that is even possible?).

It does sound like it is receiving initial data, then it stops receiving it. Does your VHF work through all of this?

Mark

[Jim Cate]

Originally Posted by colemj

Jim, you need to approach it from behind wearing a raincoat and nothing else, then say to it "hey, you got a minute?", and then when it turns around....

I don't know anything about this unit and am taking a wild stab, but have you tried bypassing the splitter to rule out that as the problem (if that is even possible?).

It does sound like it is receiving initial data, then it stops receiving it. Does your VHF work through all of this?

Mark

Good one, Mark! LOL, and Ann did too...

And the VHF seemed to be working normally without formal testing.

But see my next post for the answer to my own query.

Cheers,

Jim

[Jim Cate]

Thanks to those who tried to help. Fortunately, I stumbled into the answer on my own.

The culprit was a loose barrel connector in the VHF antenna coax. Tightened it up and the problem disappeared. Hooray!

But I'm left with the question of why this caused my odd symptoms? The fact that the initial contact with distant ships was accomplished but then the follow up transmissions were missed is perplexing to me.

At any rate, I'm delighted that the issue is put away for now.

Cheers,

Jim

[Ziggy]

Jim,
"Reflashing" is just a technogeek word for reloading the firmware. From the symptoms you describe it does sound like it may have become corrupted--it happens. I'm not sure if the firmware updates are user installable, but check ICOM tech support.
Good luck!
Z

[Wanderlust]

Originally Posted by Jim Cate

...... the initial contact with distant ships was accomplished but then the follow up transmissions were missed .....

You may find the AIS missed most signals, but the occasional one got through. A moving Class A vessel transmits at least once every 10 seconds (more frequently if fast or changing direction), and moving sailing vessels every 30 seconds.

You only need one of these messages for it to display on your screen. So if reception is borderline for a distant vessel, you could well just receive a single message at random, and miss all the others, ultimately timing out as lost. This would also explain the absence of most vessel names as static data messages are only every 6 minutes.

If you had kept the logs of data received you may learn something from examining them.

I am having a similar problem with mine, although perhaps not as bad. I would like to compare with another boat anchored nearby when I find one.

[Neptune's Gear]

Yes Jim, problem is that to get full data you need to get several sequential receptions. If you don't, it will stay unknown, like you just experienced. Pleased you found the issue, intermittent issues can be difficult!

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