AIS targets have disappeared on OCPN

[nhschneider]

A close friend of mine who is on passage with his wife from Thailand to the Maldives emailed me because he is no long getting AIS targets on OCPN. I don't have much other information (I sent him an email asking for all the details) but he is somewhat anxious about getting the problem solved as they're just about to approach the south end of Sri Lanka and the freighter traffic is very heavy there. He's pretty knowledgable about computers, connections, etc (I am not) so I'm confident he's tried all the routine troubleshooting techniques.

Any quick replies will be forwarded immediately and appreciated.

Fair winds and calm seas.

[Wanderlust]

It's a bit hard to know where to start with such a lack of information, but here goes.....

The most likely reason would be an antenna connection problem. If he's computer literate he should be able to look at the NMEA traffic (Debug window) and check to see if he's receiving the NMEA sentences and if so have a look at the content.

If he sees Own Ship on OpenCPN it indicates he is receiving some AIS messages at least. Are there messages in the log beginning with !AIVDM (messages from other vessels)? If not, check the antenna. Try plugging the VHF antenna directly into the AIS unit.

If the log shows no NMEA traffic at all, resolve the connection between AIS and PC. Could be hardware or software, or settings issue.

More information and I'm sure someone with more experience than me will chime in.

[bcn]

Some AIS units have a LED that indicates that it is sending messages.

The data input into OPCN:
If the connection is via USB consider that plugging it off and on, or changing the physical USB port may change the serial/COM port in use.

At Options|connections check wether the COM port used - drop down list of ports for the connection - does exist and modify the setting if not. Then Apply.

Plugging off can even happen without intention depending how worn the connector is.
For Troubleshooting the connector you can use the device manager under Windows. Hot (un)plugging will show the device (dis)appearing.

And what does the OCPN log say?

[nhschneider]

On behalf of my friends, Bill & Tracy, I thank those that are offering their help. Here's what Bill wrote when I pressed him for details:

I've. Booted and then plugged in. I've plugged in and then booted. I've checked the device manager for the computer and both times it says that the unit is working fine. The program shows that it is connected to the AIS by having the box on the tool bar. I've removed the AIS from the connection area and then re installed It. I'm gong to keep working on different configurations but this all started when we had the AIS plugged in and then stuck in the charger plug into the computer. Makes no sense to me but this is the second time it has done it. The last time, we got it to work again by using a new sub cable though I don't know why it would have made any difference. I used my last new cable and still no change. I've plugged it straight into the main wire from the AIS without the extension cable. Again,the computer says it's working fine but nothing comes up on the screen. Using open CPN 3.2.2 if that's any help.
Where are you that it is so beautiful? How's the anchoring? Gps way point please.
Thanks for the help
Still plodding along at 3.9 knot with two more days till we get close to Sri Lanka. Tracy wants to cut across the shipping lanes this side of the island instead of skirting the coast and doing it later.
Bill

[bcn]

First if possible I would recommend to upgrade to 4.0

Then all this looks like the "wandering COM-ports".
It is possible that the AIS resets or disables the USB port when plugging in the charger. Or due to a weak connection/worn connector just moving the AIS when plugging in the charger drops the connection. The Mini-USB ports of some units are prone to fail in this way. This can result in a different COM port. And the settings will have to be adopted to the new one.

Plugging twice may bring you back to the first one. Lottery...

Depending on the driver the COM port may not getting be released from a process. This may even require to restart the PC.
Do they have the latest USB-serial driver from the manufacturer of the AIS (Brand?) installed?
And the latest firmware of the AIS?

Hubert

[nhschneider]

The latest email from my friend, Bill, who is still struggling with getting his AIS working while on passage from Thailand to the Maldives:

The computer continually shows that the unit is working properly when I pull up the "device manager" on the computer. I've switched usb plugs from the AIS and switched to different usb plugs on the computer. With each switch, cord or different usb computer plug, the computer still says it's port 14 no matter what plug I use on the computer. After each test, the device manager still says the unit is working properly. I've restarted the computer numerous times after each change with the cord. Last time this happened, I replaced the cord and suddenly it was there. This is another brand new cord so there should be no corrosion.
Yes, I have the latest firmware from Si Tex installed.
Sorry to have you do this Neal.
Bill

[bcn]

In case you have "mini interruptions" of the connection Windows is sometimes slow to detect this, so it holds the com process for this device - while the device starts a new one. That leads to have to restart Windows in order to have a clean scenario.
Perhaps it's not the cable but the USB port at the AIS itself.

Hubert