Vesper Marine AIS

[jeffrobbins]

Originally Posted by svHyLyte

Have you seen/heard of this situation before and, if so, are you aware of a fix?

No, we haven't heard of this before. Steve (Ocean Angel) has already been in contact with our tech support and we are working with him directly to identify the cause.

[exMaggieDrum]

Originally Posted by colemj

Sure you can. You can have many, many of them. We have several GPS's connected to our NMEA network with no problem at all.

The instrument used to display the data selects the individual GPS data source to use. The other ones are then ignored, but they continue to put their data on the network.

If this wasn't true, then your advice to get a second GPS couldn't be followed because one cannot remove or turn off the GPS on the AIS.

The same is true for any other sensors, receivers, etc.

Mark

I don't think every device is smart enough to recognize which GPS data to use from which GPS. I can program my Furuno NavNet to accept one over the other but I have to select it so it will ignore the other, but I think that is only for NMEA 2000 devices. For example, engine monitoring devices for dual engines, have different device ID's so you can separate the same data types from them.

But I seem to remember that NMEA 0183 sentences do not carry a "device" specifier. Each sentence does start with GP.... for a GPS sentence but there isn't a field for identifying which specific piece of equipment sent the sentence. It's a pretty simple protocol. But lots of it is still in use as can be shown by how many devices being sold right now have 0183 capabilities. So it can be a problem if multiple devices are sending the same sentences, especially for GPS antennas that might be separated by some significant distance.

I remember that some installation instructions forbid having more than one 0183 talker with the same sentences on the same network. If you can point me to a specific example that shows different I would love to add that to my knowledge base. I am not an expert on any of this, and certainly not on AIS, so I could be mistaken. I plead Alzheimers if so.

[trantor12020]

I've ordered the XB8000. Dealer will program the mmsi number for me.
I've a gps connected to the GX2150 but plan to take nmea out from XB to the vhf set.
Question is should i also program my GX2150 vhf/ais with my mmsi number as well?
Pros & cons?
Thanks.

Ken

[jeffrobbins]

Originally Posted by trantor12020

Question is should i also program my GX2150 vhf/ais with my mmsi number as well?

Yes, you should. If the VHF doesn't have its MMSI programmed you can't use the DSC functions (eg. emergency call).

I'm not sure if the GX2150 will do this part though... with the same MMSI as your transponder it shouldn't show your own vessel following along with you. But does anyone know if the GX2150 shows yourself when the MMSI is the same as the AIS?

And thanks for choosing the XB-8000. I hope you enjoy having it.

[svHyLyte]

Originally Posted by jeffrobbins

No, we haven't heard of this before. Steve (Ocean Angel) has already been in contact with our tech support and we are working with him directly to identify the cause.

Excellent. Hopefully it's a minor glitch and done with in short order.

[colemj]

Originally Posted by jeffrobbins

I'm not sure if the GX2150 will do this part though... with the same MMSI as your transponder it shouldn't show your own vessel following along with you. But does anyone know if the GX2150 shows yourself when the MMSI is the same as the AIS?

When the AIS and GX2150 have the same MMSI, the GX2150 knows to ignore it internally and on its display(s).

HOWEVER, if one connects the NMEA output of the GX2150 to anything, they will see themselves on that device. In other words, while the GX2150 ignores its own MMSI data, it transmits these data over its NMEA output.

Strangely, if one is using a single antenna for both the radio and AIS via a splitter, one still sees themselves on the VHF NMEA data. I would have thought not, given that the splitter disconnects the radio when it transmits AIS data.

Mark

[colemj]

Originally Posted by exMaggieDrum

I don't think every device is smart enough to recognize which GPS data to use from which GPS. I can program my Furuno NavNet to accept one over the other but I have to select it so it will ignore the other, but I think that is only for NMEA 2000 devices. For example, engine monitoring devices for dual engines, have different device ID's so you can separate the same data types from them.

But I seem to remember that NMEA 0183 sentences do not carry a "device" specifier. Each sentence does start with GP.... for a GPS sentence but there isn't a field for identifying which specific piece of equipment sent the sentence. It's a pretty simple protocol. But lots of it is still in use as can be shown by how many devices being sold right now have 0183 capabilities. So it can be a problem if multiple devices are sending the same sentences, especially for GPS antennas that might be separated by some significant distance.

I remember that some installation instructions forbid having more than one 0183 talker with the same sentences on the same network. If you can point me to a specific example that shows different I would love to add that to my knowledge base. I am not an expert on any of this, and certainly not on AIS, so I could be mistaken. I plead Alzheimers if so.

If we are considering just NMEA2000, then every device is smart enough to be configured to use a specific data source, and multiple sources of similar data can exist on the network with no problem.

For NMEA0183, one cannot just wire multiple talkers of any type of data together. A multiplexer is necessary but, again, multiple sources of similar data can be on the network, with one port selected for main use. Some of the multiplexers even have intelligent switch-over in case of failure.

In all these cases, other similar data sources are ignored, but they do not need to be disconnected. It is no different than having a wind data source on the network, but no instrument to read it.

In the case of AIS, one cannot turn off its dedicated GPS source. So to use a different GPS as a main receiver, one just puts both on the network and chooses the non-AIS GPS.

Mark

[jeffrobbins]

Originally Posted by colemj

In the case of AIS, one cannot turn off its dedicated GPS source. So to use a different GPS as a main receiver, one just puts both on the network and chooses the non-AIS GPS.

You can't turn it off for its own internal use. But for output to other devices....

As far as I know, other AIS transponders don't output GPS PGN's onto the NMEA 2000 network. I've looked at their PGN list and I can't find any with the necessary GPS PGN's as being output. So if that's the case then they can't be used as a positioning source. The Vesper XB-8000 & Vision do output all the required PGN's to be a primary position source and so you can choose to use it or not on your displays. They also have high speed 5Hz calcs which you can enable if you wish.

But for 0183 you can usually tell most (all?) transponders to not output GPS sentences.

[colemj]

Good point about cutting output of the 0183 - I am always thinking N2K.

I didn't realize that others did not put output on N2K - good on you!

Mark

[trantor12020]

1. I've hooked up my XB with dealer supplied cable to the splitter SP160 and antenna VA159 with VM supplied cable. Connect gps, power up, got VSWR shows 6 and status light Amber. So not good I suppose.

2. Moved the antenna a little now VSWR is 7 with status light Green. Is this ok? Should good VSWR be 2 or lower?

Anything I could/should do?

Ken

[trantor12020]

Originally Posted by trantor12020

1. I've hooked up my XB with dealer supplied cable to the splitter SP160 and antenna VA159 with VM supplied cable. Connect gps, power up, got VSWR shows 6 and status light Amber. So not good I suppose.

2. Moved the antenna a little now VSWR is 7 with status light Green. Is this ok? Should good VSWR be 2 or lower?

Anything I could/should do?

Ken

Now I've got VSWR of 1. Ok so maybe it takes time for the system to stablise. All seems good. This weekend will setup on boat. Fingers-X.

Ken

[jeffrobbins]

Originally Posted by trantor12020

Now I've got VSWR of 1. Ok so maybe it takes time for the system to stablise. All seems good. This weekend will setup on boat. Fingers-X.

Just curious... did you have the antenna with nothing but free-space around it? Or was it near other objects or people?

[trantor12020]

Originally Posted by jeffrobbins

Just curious... did you have the antenna with nothing but free-space around it? Or was it near other objects or people?

Left antenna on some magazines on table.

[trantor12020]

Was on the boat last weekend testing the new XB-8000. One thing leads to another and before I know it, I've installed the works right in the cabin. I choose to leave the GPS antenna inside as I've no problem picking up the satellite signal. I've a patch box where I supply 12V to the AIS and Splitter as well as connecting the NMEA OUT from AIS to GX2150 NMEA IN. Apart from need to set the AIS NMEA OUT to 4800 baud, everything works right out of the box!
I'll need to tidy up the wirings.

[jeffrobbins]

Originally Posted by trantor12020

I choose to leave the GPS antenna inside as I've no problem picking up the satellite signal.

Glad to hear it's all working well. However, I do suggest rotating the GPS antenna so the mushroom top is upwards. I'd expect that orientation to be better and more reliable.