AIS Transceiver in VHF

[roverhi]

If the 6500 is like the 2200 it probably doesn't need an antenna splitter as conflicts between the VHF voice and AIS data would be handled internally in the radio. If it didn't there would little reason to combine the two types of trasmissions in one package.

[Don C L]

I'm still waiting on this question of splitter from WM. NMEA 2000 too. If this really is a complete package for 800 I wonder how Vesper will compete? Around here, regularly crossing a very active shipping lane, this is a pretty amazing little radio/transponder for $800 to me having grown up with ded. reckoning and the most advanced stuff on a little boat was an RDF and LORAN.

[barnakiel]

Originally Posted by roverhi

If the 6500 is like the 2200 it probably doesn't need an antenna splitter as conflicts between the VHF voice and AIS data would be handled internally in the radio. If it didn't there would little reason to combine the two types of trasmissions in one package.

I think it uses two antennas.

It is a transceiver AIS so it would not access DSC on the VHF with a splitter. Probably not legal as DSC is obligatory on new VHF radios.

http://www.panbo.com/assets_c/2016/1...auto-14331.jpg

I think the image is the connector side of the 6500.

Cheers,
b.

[PassportJoy]

Vespar makes a splitter & AIS/VHF antenna. With it on the masthead my AIS reception and signal are much stronger than a rail mount AIS antenna.

[daletournier]

I justed fitted the vesper ais with their splitter, im picking up ships 22nm away. Its not cheap though..ouch!

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[sailjumanji]

Is the SH unit going to have an integrated splitter, or require either an external splitter or a separate antenna? I would be concerned about a single unit/box doing VHF and AIS transponder/transceiver and splitter all together. Frankly, I prefer separate units. To me, best in class is Icom VHF and Vesper AIS and splitter. Plus, I can look at the diagnostic lights on my Vesper XB8000 and the antenna splitter, and it should provide insight if either of those are not working properly. What's SH going to have to do same?

Oh, and if you have a NMEA2000 compatible VHF radio (like my Icom M506, without AIS), and a Vesper AIS on the NMEA network, you can select AIS targets on the Icom screen to make a direct DSC call. But honestly, I've had better luck just getting the target info off of the chartplotter, and hailing them by name on the working channel. A lot of ships do not answer DSC, in my experience. They almost always answer a hail on working channel.

Yes, and I see AIS targets over 20 nm miles away too. I have a combination VHF/AIS antenna is at the top of the mast. I know its a risk using a splitter, but if I put a separate AIS antenna on the stern rail, I'm sure the AIS target distance would be significantly less. If the splitter craps out, its easy to delete it and screw the VHF antenna cable directly to the radio. It's only been a couple of years of use, but the Vesper unit and splitter have been flawless so far.

[DotDun]

Originally Posted by sailjumanji

Yes, and I see AIS targets over 20 nm miles away too. I have a combination VHF/AIS antenna is at the top of the mast. I know its a risk using a splitter, but if I put a separate AIS antenna on the stern rail, I'm sure the AIS target distance would be significantly less.

I have to ask as I've seen more than you stating seeing AIS targets over 20nm away.

What navigational value is there is seeing a target 20nm away on a vessel doing <10kts?

[sailjumanji]

Originally Posted by DotDun

I have to ask as I've seen more than you stating seeing AIS targets over 20nm away.

What navigational value is there is seeing a target 20nm away on a vessel doing <10kts?

If you are traveling at the ais target, it's nice to have as much advance warning as possible. You get sport fishers crossing to Bahamas that travel pretty fast and are not always best at keeping watch.

I've also used ais to identify boat to call at an anchorage and ask about crowd and entry conditions. If no room, we would have diverted.

But otoh if you want an ais system with limited range, I suspect there are plenty available.

[DotDun]

Originally Posted by sailjumanji

If you are traveling at the ais target, it's nice to have as much advance warning as possible. You get sport fishers crossing to Bahamas that travel pretty fast and are not always best at keeping watch.

I've also used ais to identify boat to call at an anchorage and ask about crowd and entry conditions. If no room, we would have diverted.

But otoh if you want an ais system with limited range, I suspect there are plenty available.

So you don't actually do anything with the data, it's just nice to know.

My point is that a splitter adds failure points to your VHF comms so you can see AIS targets at distances that don't matter. There is nothing you are going to do navigation-wise 30 minutes TCPA from a recreational vessel. I'd be surprised if you altered course before 10 minutes TCPA. Hence, a rail mount AIS antenna provides all the navigation data needed for collision avoidance.

[s/v Jedi]

Originally Posted by DotDun

So you don't actually do anything with the data, it's just nice to know.

My point is that a splitter adds failure points to your VHF comms so you can see AIS targets at distances that don't matter. There is nothing you are going to do navigation-wise 30 minutes TCPA from a recreational vessel. I'd be surprised if you altered course before 10 minutes TCPA. Hence, a rail mount AIS antenna provides all the navigation data needed for collision avoidance.

I agree with you that a splitter adds a point of failure, but so does an extra antenna and, more negatively, an extra coax cable.

If you add sensors to your electronics then it makes sense to make them as good as possible. Why not receive AIS targets 50nm away? Why would that hurt you when you can simply reduce the range on your plotting device?

Let me give the reason why you want AIS to use your masthead antenna: The targets you see very far away are probably big ships that have their antennas at high elevation as well. But not everybody has that. If you would use an antenna attached to your rail, do you think that you are the only one doing that? Have you calculated the range between two class-B AIS transceivers with their antennas 4 feet above sea level? (it is only 4nm) Having your antenna at the masthead, you can see all targets. If your antenna is at 50' elevation and the other station is at 4' elevation, the maximum range of detection is 10nm which is a solid, workable situation.

Now let's say the antenna switch fails. You can simply install a manual switch if you don't want to carry a spare automatic switch. Or you connect the antenna directly to the AIS transponder and connect an emergency antenna to the VHF. This is an easy failure to deal with.

Of-course, the best solution is to buy a ketch and have two mast heads for installing antennas

[DotDun]

Originally Posted by s/v Jedi

I agree with you that a splitter adds a point of failure, but so does an extra antenna and, more negatively, an extra coax cable.

I don't understand how a separate AIS antenna and coax adds more failure points to VHF comms (which was my earlier point).

Originally Posted by s/v Jedi

If you add sensors to your electronics then it makes sense to make them as good as possible. Why not receive AIS targets 50nm away? Why would that hurt you when you can simply reduce the range on your plotting device?

Why did the designers make Class B 2 watt? Maybe to limit the distance???

Originally Posted by s/v Jedi

Let me give the reason why you want AIS to use your masthead antenna: The targets you see very far away are probably big ships that have their antennas at high elevation as well. But not everybody has that. If you would use an antenna attached to your rail, do you think that you are the only one doing that? Have you calculated the range between two class-B AIS transceivers with their antennas 4 feet above sea level? (it is only 4nm)

No need to calculate, I have real-world experience.

Originally Posted by s/v Jedi

Having your antenna at the masthead, you can see all targets. If your antenna is at 50' elevation and the other station is at 4' elevation, the maximum range of detection is 10nm which is a solid, workable situation.

Rail-mount to rail-mount Class B is 4nm to 8nm.

What do you do navigation-wise when you see a Class B vessel at 10nm? The answer is nothing! Hence, my point, for navigation you don't need to see Class B at 10nm nor Class A at 20-50nm.

Originally Posted by s/v Jedi

Now let's say the antenna switch fails. You can simply install a manual switch if you don't want to carry a spare automatic switch. Or you connect the antenna directly to the AIS transponder and connect an emergency antenna to the VHF. This is an easy failure to deal with.

It's easy to deal with except during an emergency when you really need the VHF comms...

Originally Posted by s/v Jedi

Of-course, the best solution is to buy a ketch and have two mast heads for installing antennas

No arguing with that!

I really don't care if someone adds an antenna splitter to their VHF comms, it's their boat. Plus I believe Vesper has a good unit.

My real point is more for the newbies reading this thread thinking they need to see approaching vessels at 10, 20, 50nm away in order to avoid a collision. That's pure BS!!!

It's like the guy I was talking to and he was complaining the PO of his boat installed a depth sounder that only read to 200'. He said he doesn't fish, I asked him the draft of the boat.....he didn't get it.

[sailingharry]

Originally Posted by John_Trusty

Ron,
I think that you would be overloaded with hits around any busy port like New York -- it's just too crowded with commercial vessels. For us, AIS has its benefits in the middle ground of crossing commercial traffic where you otherwise do not notice (or can't see) if it is around - a poor man's radar. In busy harbors, we do not turn it on because there are too many close-aboard CPA notices.

Check out this live view of traffic centered on NYC -- MarineTraffic: Global Ship Tracking Intelligence | AIS Marine Traffic

You are right about traffic overload. Unfortunately, it's not the commercial traffic that are the problem -- it's the self-important recreational boats that have destroyed AIS usefulness. Unless you set the alarm range WAAAY down, you'll have dozens of alarms an hour -- every few minutes. And your screen will be so cluttered with contacts that you can't easily tell which one is the tug and tow (without cursoring to each contact). It would make it SO MUCH more useful if you could filter out the AIS-B contacts. At times (night, offshore, etc), Class B is useful -- but where/when I sail, the answer to Class-B "alarm fatigue" is to turn off the radio, a really crappy solution.

[sailjumanji]

Originally Posted by DotDun

So you don't actually do anything with the data, it's just nice to know. .

Hmm, I don't remember writing that anywhere. I actually gave you one example of what I did with an AIS target exceeding 20 nm distance.

Originally Posted by DotDun

I'd be surprised if you altered course before 10 minutes TCPA. Hence, a rail mount AIS antenna provides all the navigation data needed for collision avoidance.

Altered course before 10 nm TCPA - yeah, not likely. But probably contact the AIS target. Which my far-reaching AIS setup allows me to do - to identify the target by name.

I'll give an example. We were crossing Gulf Stream heading to Bahamas last March. Night crossing. A cruise ship was coming from port side. We had AIS transponder and radar. A buddy of mine was traveling on same catamaran model about 300 yds behind us. No AIS on his boat. We were sailing, beating, and holding a pretty solid course. Cruise ship was motoring at good clip and holding course. AIS prediction for a long time was crossing at distance of about 200 feet. (Too close) I hailed ship by name, and had a short conversation just to make sure he was aware. He saw us, but did not see buddy boat on radar until we pointed him out. Cruise ship altered course to pass no closer than a mile from us. Nice guy - good communication.

You can put your AIS antenna wherever you want. And as you point out, a ship 20 nm away is not as threatening as one 2 nm distance, and closing on a collision course. But there are instances where it is nice to be able to hail another cruiser by name at a destination, that AIS allows you to get the boat info to call. Or when you're 20 nm out from the Port of Galveston and see there are over 50 ships anchored out, and very few moving in the channel, that something is amiss.

And if the splitter fails, it takes less than a minute to bypass it. In the meantime, there is a handheld VHF within reach.

Ok, so my original point was that, many people have issues with splitters, and extoll the virtues of separate antennas and redundancy. But OTOH, they are getting so excited about an all-in-one VHF and AIS transponder. If I lose a VHF or the AIS, I only lose that one unit. If I lose a powered splitter, then I delete the AIS. But I still have a powerful VHF with masthead antenna. But maybe it makes sense to buy another Vesper splitter and throw it in the spares box before leaving on the next cruise.

[moniia]

My AIS (Vesper) picks up ships from about ninety miles. Pretty useless for collision avoidance, granted. Unless, like me, you sail alone, and that gives you peace of mind for longer (than five minutes ) nap. And because I know, that it does pick it up sometimes from such a distance (I wouldn't count on that) so I know that it should get everything on AIS from half of that.
It still doesn't mean I can sleep for hours, plenty of stuff does not have AIS - but there is a better chance of 30 minute nap...

Using splitter would probably half that. Don't know, small antenna on upper spreader (40' above water) is not a problem and works, as proved - brilliantly.

[sailjumanji]

Originally Posted by sailingharry

You are right about traffic overload. At times (night, offshore, etc), Class B is useful -- but where/when I sail, the answer to Class-B "alarm fatigue" is to turn off the radio, a really crappy solution.

Cant you turn off the alarm feature? (I don't have the alarm turned on for either the VHF - that sees the AIS targets as well - or the chartplotter.) Or just turn off the AIS in a crowded port. Can't you do that without turning off the radio?