AIS

[Porsche49]

Sorry if this has been asked before.
I'm about to buy an AIS class B transducer and am keen on the Digital Yacht AIT 3000 or the Weather dock equivalent. Apart from the built in GPS antenna in the Weather dock they seem to be the same.
Has anybody got any experience with either of these units and will they talk to my Raymarine E series Classic without any trouble?

[sailjumanji]

Two friends had digital yacht units that failed in less than a year. I purchased a vesper unit instead and been very happy with it.

[Porsche49]

Thanks for the response. I'll have a look into the Vesper unit. I was hoping to get away without the hassle of an separate splitter or GPS antenna etc.
But maybe the separate units will be more reliable in the long run.

[MarkJ]

I believe every AIS is required to have its ownGPS antenna.

And a splitter is not necessary if you give it its own vhf antenna.

They are "big" electronics so its not just plug n play

[Porsche49]

I've seen a couple of models boasting an integral splitter and some boasting integral GPS antenna also. It's seems that would be a lot less cables and connections to go wrong in the future. I wondered about the strength of the GPS integral antenna but I've just purchased a new VHF with integral GPS antenna and it's faultless so far. It finds it's location faster than other instruments with their own external GPS antenna.

[a64pilot]

My Vesper has an internal GPS, and despite it being below and mounted directly under the VHF, the GPS reception is pretty good, I assumed I'd need an external antenna, but I don't.
I did use the splitter after finding out the splitter actually improves performance, not degrades it as I would have thought. It is a very easy install actually, just power and connect to the VHF antenna

[Ziggy]

Originally Posted by MarkJ

I believe every AIS is required to have its ownGPS antenna.

And a splitter is not necessary if you give it its own vhf antenna.

They are "big" electronics so its not just plug n play

That's true for transponders, but I don't think it's a requirement for receive only units.

[BriaF]

I am in the process of buying ais
My choice is the vesper xb8000 why ?
Already have iPads so can use app.
If there are a lot of targets around then a plotter screen will become very cluttered.
It has wifi to connect to tablets
It will translate nmea 0183 to nmea2000 & visa versa.
It can also be wired to plotters, I would think this is most useful on
ocean passages (not coastal) were there is minimal traffic.

[Porsche49]

I've looked at the Weatherdock and the digitalyacht. they both have wi-fi and the antenna splitter. Plus other functions. The weatherdock has the intergral GPS. There both transponders. I fancy the weatherdock version as there's a lot less work to do not having to install the antenna on an already crowded stern. I'll look into the Vesper in more detail, although I think the cost of the splitter will make it more expensive in the end. I was more concerned about the reliability between them.

[capt jgw]

Originally Posted by Porsche49

I've seen a couple of models boasting an integral splitter and some boasting integral GPS antenna also. It's seems that would be a lot less cables and connections to go wrong in the future. I wondered about the strength of the GPS integral antenna but I've just purchased a new VHF with integral GPS antenna and it's faultless so far. It finds it's location faster than other instruments with their own external GPS antenna.

On a glass boat internal GPS antennas usually work fine. FG is pretty much invisible to radio energy so the receiver can't tell the difference. On a metal boat you have to go external.

[barnakiel]

Originally Posted by Ziggy

That's true for transponders, but I don't think it's a requirement for receive only units.

OP asked about transponders. Mark was talking about transponders too.

Which points towards an interesting question: why is the built-in gps a (regualatory?) requirement?

We could have slightly cheaper transponders if we could build gps-less units. Right, wrong?

b.

[MarkJ]

Originally Posted by barnakiel

Which points towards an interesting question: why is the built-in gps a (regualatory?) requirement?

We could have slightly cheaper transponders if we could build gps-less units. Right, wrong?

b.

There is a reason, but I forget what it is. (I am not doing a good post so far!)

The GPS adding expense is correct because if the unit has an external GPS antenna (the mushroom thing) the actual GPS must, by law, be in the mushroom. So its not just an antenna. Its the whole thing.

But I am stuffed if I remember their stupid, e pensive reason why you can't have your own normal GPS plugged in from your plotter etc.

[a64pilot]

A GPS is just a chip now, and can even be integrated into existing chips, hence you can have cell phones and watches with GPS's, so unless there is some kind of royalty that has to be paid, GPS ought to be very cheap really.
Reminds me of cell phones years ago, the flip phones had just came out and I wanted one that vibrated as I work in noisy environments, but could not justify the extra $100 or so one costs. Kid threw the phone in the toilet and it started vibrating, apparently all Motorola Star Tacs had vibrators, it just cost $100 to have it enabled.
Bet GPS is similar to that.

It's my understanding the built in GPS requirement for AIS is to ensure accuracy, if you allowed external position data to be imported, how do you determine it's accuracy?

[barnakiel]

Originally Posted by a64pilot

(...) if you allowed external position data to be imported, how do you determine it's accuracy?

Make GGA or a similar sentence obligatory. No GGA, the unit becomes a receiver only. Seems simple.

I am listening. I may have understood your question wrong.

b.

[Jman]

Originally Posted by MarkJ

There is a reason, but I forget what it is. (I am not doing a good post so far!)

The GPS adding expense is correct because if the unit has an external GPS antenna (the mushroom thing) the actual GPS must, by law, be in the mushroom. So its not just an antenna. Its the whole thing.

But I am stuffed if I remember their stupid, e pensive reason why you can't have your own normal GPS plugged in from your plotter etc.

I have a brand new Vesper XB8000, external GPS antenna appears to be connected with a coax cable, not a power/data cable. Not sure what "law" you are referring that states the whole thing must be in the antenna.


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