AIS-VHF Antenna Splitter

[Hello Below]

Dig deeper into the software for the AIS and CP. There is often a way to filter the targets to eliminate those that are not moving or not a danger. When transiting NY Harbor, I turned off the AIS as there were so many targets I couldn't see the chart!

If the description of the target is a number or seemingly random 2 or 3 letters it may be an EATON, Electronic Aide to Navigation. These targets are actually buoys and the the AIS signal is not broadcast from the buoy, rather it is broadcast over land based stations which cover many more miles.

@dlochner, I can only speak for the Raymarine Lighthouse MFDs and as reported in the Raymarine forum thread:
" Unfortunately, hiding the stationary targets does not help. Doing this seems to only hide the stationary targets on the chart but they still appear in the AIS Targets list and continue to count toward the 100-target limit. For example, if I look at the AIS target list I see a large number of targets showing 0.0 kn SOG (even though the hide stationary targets option is set to "on". And if I press the "show on chart" button for any of the 0.0 kn SOG vessels, the chart zooms to an empty patch of water (e.g., a slip in my marina) where the boat is tied up but no AIS target is shown on the chart, because it's hidden."

I believe as more and more AIS transmitters come in use this is a major shortcoming in the Lighthouse software.

 

[dlochner]

@dlochner, I can only speak for the Raymarine Lighthouse MFDs and as reported in the Raymarine forum thread:
" Unfortunately, hiding the stationary targets does not help. Doing this seems to only hide the stationary targets on the chart but they still appear in the AIS Targets list and continue to count toward the 100-target limit. For example, if I look at the AIS target list I see a large number of targets showing 0.0 kn SOG (even though the hide stationary targets option is set to "on". And if I press the "show on chart" button for any of the 0.0 kn SOG vessels, the chart zooms to an empty patch of water (e.g., a slip in my marina) where the boat is tied up but no AIS target is shown on the chart, because it's hidden."

I believe as more and more AIS transmitters come in use this is a major shortcoming in the Lighthouse software.

Well, that sent me back to the manual for my B&G Zeus3s.

The Zeus can show all targets or a user defined max number. There is no indication in the manual of a predetermined max target limit. Targets can also be filtered by speed, CPA, Time CPA, range based on the radar setting. It can show all targets, dangerous targets, or no targets.

 

[stephen_i_w]

The number of vessels with AIS transponders increases every season. I can easily see how the 100 target limit could be a problem on my Raymarine MFD (older Lighthouse 2 model) in my area.

Fortunately, one workaround is to install a wifi gateway on the NMEA network. I have both an iPad and a Samsung Android Tablet. I connect them to my wifi gateway. Both show AIS targets picked up by my transponder on my Navionics app. Actually, so does my laptop running Open CPN. I understand that many AIS transponders also have built in wifi capabilities.

My MFD (older Lighthouse 2 model) does have a built in wifi, but unfortunately, it does not appear to pass through NMEA data. So, the wifi gateway is necessary for me.

 

[dlochner]

The number of vessels with AIS transponders increases every season. I can easily see how the 100 target limit could be a problem on my Raymarine MFD (older Lighthouse 2 model) in my area.

Fortunately, one workaround is to install a wifi gateway on the NMEA network. I have both an iPad and a Samsung Android Tablet. I connect them to my wifi gateway. Both show AIS targets picked up by my transponder on my Navionics app. Actually, so does my laptop running Open CPN. I understand that many AIS transponders also have built in wifi capabilities.

My MFD (older Lighthouse 2 model) does have a built in wifi, but unfortunately, it does not appear to pass through NMEA data. So, the wifi gateway is necessary for me.

I'm not sure I'm following this. The Navionics app does not have a AIS transponder, it can only serve as a display for an AIS receiver which supplies the data over a NMEA wifi network. Do you have an AIS transponder or receiver?

 

[Hello Below]

I can easily see how the 100 target limit could be a problem on my Raymarine MFD (older Lighthouse 2 model) in my area.

If it is any condolence the newest chartplotter that Raymarine has just made available, the Axiom 2 Pro series, runs under the Lighthouse 4 operating system which still only displays the nearest 100 targets to your vessel. The same number as yours and mine. To me this one short coming is a showstopper if I were currently purchasing a new MFD. This issue has been well know to RM for over 5 years yet has not been addressed over that period. I hope someone can correct me if I am wrong about this issue.

 

[dlochner]

Looking at the Navionics website again, I see they do offer live AIS through a third party which requires an internet connection. The receiver is not in the app, it is a display of data collected from other sources and transmitted over the net, sort of like a realtime mobil MarineTraffic.com.

 

[stephen_i_w]

I'm not sure I'm following this. The Navionics app does not have a AIS transponder, it can only serve as a display for an AIS receiver which supplies the data over a NMEA wifi network. Do you have an AIS transponder or receiver?

I have a Vesper (XB-6000) transponder on my NMEA2000 network. The transponder both sends out my AIS target data and also receives AIS target signals from other vessels. The transponder puts the received AIS target data on the NMEA network and the wifi gateway puts the NMEA data out over wifi. Tablet computers, running Navionics, connected to the wifi, display the AIS targets. No Internet connection needed.

This also works with receive only AIS devices such as the Standard Horizon GX2400.

 

[dlochner]

I have a Vesper (XB-6000) transponder on my NMEA2000 network. The transponder both sends out my AIS target data and also receives AIS target signals from other vessels. The transponder puts the received AIS target data on the NMEA network and the wifi gateway puts the NMEA data out over wifi. Tablet computers, running Navionics, connected to the wifi, display the AIS targets.

I didn't understand that. Are you using the Vesper's built-in wifi? It can support up to 5 devices.

 

[stephen_i_w]

I didn't understand that. Are you using the Vesper's built-in wifi? It can support up to 5 devices.

The XB-8000 has a built in wifi, I have an XB-6000 which does not have a wifi.

 

[quadrille38]

No idea where you got the 5 nm, perhaps it's the unit you are running, but my AIS with antenna mounted on the stern rail works well, even in large waves (where I could see boats appear and disappear at the 25 nm range) at pretty much 25 nm, sometimes further.

dj

p.s. why would you care to see beyond the lake you are sailing in? What does that do for you? Just a question...

The lake we sail on is about 7 miles long. It is connected to Lake Michigan through a channel. From one end of the lake our AIS mounted on the Bimini frame can see boats at the other end. It cannot see over the dunes and into Lake Michigan to see boats there. Friends with masthead mounted ais can see boats in Lake Michigan on the other side of the dunes. We both run Digital Yachts AIS systems.
When we are out on the open water I can see boats and ships further away (up to 20 miles) but still not as far as the masthead mounted antenna friends have (40 to 60 miles).

 

[dlochner]

The XB-8000 has a built in wifi, I have an XB-6000 which does not have a wifi.

I think I need to increase the font size on my computer. These eyes aren't what they used to be.

 

[dLj]

The lake we sail on is about 7 miles long. It is connected to Lake Michigan through a channel. From one end of the lake our AIS mounted on the Bimini frame can see boats at the other end. It cannot see over the dunes and into Lake Michigan to see boats there. Friends with masthead mounted ais can see boats in Lake Michigan on the other side of the dunes. We both run Digital Yachts AIS systems.
When we are out on the open water I can see boats and ships further away (up to 20 miles) but still not as far as the masthead mounted antenna friends have (40 to 60 miles).

So you might want to see if a boat is coming up that channel?

I can't say I've seen boats at 40 to 60 miles out even though I do (as I've just found out) have a mast head antenna. I've only begun really assessing when they are about 25 nm away. Even at 20 knots 40 miles away is 2 hours. Most commercial freighters run around 12 knots. I think the fastest one I've seen might have been around 15 knots. Some down around 10. I start thinking about them at an hour away, more or less... if it looks like we won't get closer than about 2.5 nm, I don't worry about them. Although I will look to see where they are from and the like, but as it's been said, that's purely entertainment....

dj

 

[Jim Legere]

No mention of radar in this thread. I don't dispute the convenience (and safety) of AIS but don't get lulled into a false sense of security when operating in low visibility...many small craft, like sailboats and fishing boats, are not equipped with AIS transmitters or choose not to turn them on (particularly fishing boats). Yes, radar is more demanding to operate but, if adjusted correctly, it sees damn near everything, including coastlines, buoys, and thunderstorms. I am suggesting that a bluewater yacht operating in reduced visibility needs both. In my opinion, if it only has one, it should be radar before AIS.

 

[dLj]

No mention of radar in this thread. I don't dispute the convenience (and safety) of AIS but don't get lulled into a false sense of security when operating in low visibility...many small craft, like sailboats and fishing boats, are not equipped with AIS transmitters or choose not to turn them on (particularly fishing boats). Yes, radar is more demanding to operate but, if adjusted correctly, it sees damn near everything, including coastlines, buoys, and thunderstorms. I am suggesting that a bluewater yacht operating in reduced visibility needs both. In my opinion, if it only has one, it should be radar before AIS.

I can't agree with you more! RADAR is very powerful and as you say, not all boats use AIS.

When I was running at night and/or in reduced visibility I ran both my RADAR and my AIS. Absolutely a major advantage!

dj

 

[stephen_i_w]

Boats have an infinite capacity to absorb money.

The great thing about AIS, it that it is relatively inexpensive. Several VHFs on the market include the capacity to receive AIS data. Also, AIS receive only devices cost less than AIS transponders. If you have Internet access on the water, there are free apps and web pages that will display AIS targets. All commercial vessels are required to transmit AIS data and a growing number of private vessels also transmit AIS.

So, what about private vessels that do not have AIS transponders? Well, you still have to watch out for them. My experience with the Radar that came with my boat is that, often, smaller power boats and sailboats with carbon masts are difficult to see on Radar. My two eyes spot them far earlier. At night and in overcast, certainly Radar is useful. But, so would an infrared camera at $2000.

Having used Radar for 5 seasons now, if Radar had not already come with my boat, I doubt that I would spend the $5000 or so required to add that capability.

 

[dlochner]

As with all else on a boat, whether radar or AIS is more valuable depends on how and where you use your boat. In places that are often beset with thick fog, radar is probably slightly more valuable than AIS because it is useful in ways that AIS isn't, i.e., finding the shoreline in the fog, seeing small boats, finding AtoNs, measuring distance in tight anchorages, spotting squalls, and who knows what else. On the high seas and approaching major harbors, I'd give the nod to AIS for the ability to see and be seen by large commercial ships.

In a year long trip, I relied on radar to navigate exactly twice. The AIS was on every day and was especially helpful on the ICW and high traffic areas.

 

[jssailem]

No mention of radar in this thread

That is because the query was about the use of a splitter for VHF/AIS antennas… Radar would. Be thread drift. Please start a thread about systems to help you navigate in low visibility, to compare Radar and AIS.

 

[Jim Legere]

That is because the query was about the use of a splitter for VHF/AIS antennas… Radar would. Be thread drift. Please start a thread about systems to help you navigate in low visibility, to compare Radar and AIS.

Well, EXCUSE ME ! From about post #27 on, this thread has devolved into discussion of the range, effectiveness, and safety of AIS...it seemed à propos to mention some of the shortcomings of AIS and how other devices like radar can be complientary to AIS. Sorry I drifted into a safety discussion once the technical points of splitters vs. separate antennae had been thrashed out...

 

[dlochner]

Gentlemen, let's not get our spinnakers in a knot. Threads drift is a common issue and in this case the drift was not that far off topic.

So, let's keep the moderators at bay and keep things civil. If you are no longer interested in the topic, then just sail on by.

 

[Lee Hadjiosif]

Thank you all for your very valuable suggestions. My question is strictly a technical one. Is the splitter issue only when both VHF and AIS are trying to transmit at the same time? If yes, I can handle it with switching to AIS silent mode when I need to transmit on the radio(very rare). After all, with a receive only AIS there is never an issue of the VHF damaging the AIS. I'm thinking that switching to silent mode, it would be like having a receive only AIS which doesn't need a powered splitter. Or is there a technical issue than I'm overlooking? Strictly technical answer please. Thanks.