No vessel name on AIS but everything else

[Tudorsailor]

I am running OpenCPN I have windows XP PC AIS comes from Comar multi which includes VHF splitter and goes direct to the USB

I was under the impression that lots of boats were not showing their boat name but recently realised that this is not the case. Every other information seems OK, MMSI, GPS position, rate of turn

The Comar is a dual channel receiver Comar Systems AIS-Multi

Sometimes the boat name is shown but rarely.

IS there something that I should do to make the boat name always appear??

Thanks

Tudorsailor

[bcn]

AIS distinguishes between static and dynamic data.

The second ones are updated more frequently and include the data you are mentioning.
Static data may need several minutes to show up and include items like the ship's name, dimensions or in the case of AIS Class A units destination and ETA.
You can see very easily if static data are available: the color of the icon turns to green from yellow.
For further information I would suggets to consult O's online manual (the "?" button).

If the static data does not turn up with a bit of patience you might check the antenna as well: if you have a poor reception, the static data are more probable to be "overseen" by the Comar.

[s/v Moondancer]

We run a different system but we find a significant distance difference in the two types of data, we get the basics at 20-25 miles but need to be closer, about 12-15 miles to get the name.

We use a splitter but the antenna is 76 ft above the water so we get exceptional reception.

[Bregts]

I had the same problem for a time. Only the dynamic data showed up. Resulting in having to call ships on vhf by there location or mssi. Turned out the ais antenna plug was not inserted in the ais transponder all the way. Once I fixed this I could see the static data of almost all vessels.

[bcn]

Originally Posted by s/v Moondancer

We run a different system but we find a significant distance difference in the two types of data, we get the basics at 20-25 miles but need to be closer, about 12-15 miles to get the name.

We use a splitter but the antenna is 76 ft above the water so we get exceptional reception.

Phil, this is logical:

the dynamic data are sent (Class A) depending on SOG of the vessel every 6 or 10 sec (or even more often when turning) while static data are sent every 6 minutes. Even if you miss 80% of the dynamic messages you will have the target identified and can track it (would be a report update every 30 or 60s), while missing the same number of packets in the case of static data would imply 30 minutes.

For class B the dynamic updates are
Class B “SO” shipborne mobile equipment not moving faster than 2 knots 3 mins
Class B “SO” shipborne mobile equipment moving 2-14 knots 30 secs
Class B “SO” shipborne mobile equipment moving 14-23 knots 15 secs

[Paul Elliott]

Originally Posted by bcn

Static data may need several minutes to show up and include items like the ship's name, dimensions or in the case of AIS Class A units destination and ETA.

A vessel sends its static data is once every six minutes. If you are using a single-channel receiver (not the case with the OP) you will only get half of those transmissions. If the signal is weak or there is interference, some percentage of the transmissions will be garbled and discarded.

So, it can take a while for the static data to appear, and if you have poor connections, cable, etc, it can take a long time.

[Tudorsailor]

Originally Posted by bcn

Phil, this is logical:

the dynamic data are sent (Class A) depending on SOG of the vessel every 6 or 10 sec (or even more often when turning) while static data are sent every 6 minutes. Even if you miss 80% of the dynamic messages you will have the target identified and can track it (would be a report update every 30 or 60s), while missing the same number of packets in the case of static data would imply 30 minutes.

For class B the dynamic updates are
Class B “SO” shipborne mobile equipment not moving faster than 2 knots 3 mins
Class B “SO” shipborne mobile equipment moving 2-14 knots 30 secs
Class B “SO” shipborne mobile equipment moving 14-23 knots 15 secs

Can you tell me the ideal settings on the PC especially the baud rate?
thanks
ts

[bcn]

Originally Posted by Tudorsailor

Can you tell me the ideal settings on the PC especially the baud rate?
thanks
ts

Should be 38400

[Paul Elliott]

Originally Posted by Tudorsailor

Can you tell me the ideal settings on the PC especially the baud rate?
thanks
ts

As bcn said, for AIS the bit rate is 38400 bps. The other settings are eight data bits, no parity, but I would be quite surprised to see an AIS-aware program get these wrong.

And, if the serial port is set incorrectly you will get no data through whatsoever. When it comes to these settings there's no such thing as "almost right". They're either correct or incorrect.