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Adding AIS

supersailor

Contributing Partner
After many years of dodging traffic on the Straights here, I am ready to ask for an AIS of some type for my birthday. Port Angeles is a focal point for marine traffic as all ships stop here to pick up Puget Sound Pilots. I have a Raymarine HD radar on an aft mast and I am planning to add a second VHF antenna to the mast and will read the AIS on a Raymarine E-90. The AIS could function off this antenna.

I think I really just want to know the positions, speed, and direction of the AIS equipped traffic out there so I can stay clear. There are those here that argue that it's important for them to "see" you too. If I go with the AIS B (transmit and receive), I know it is important to get one of the newly approved 5 watt units rather than the 2 watt units now being sold. There is also a lot of Government tape that comes with the transmit also.

There is also the question of how big I can inflate the birthday gift.

What do you guys with the AIS feel about This?
 

bgary

Advanced Beginner
Blogs Author
I have a Vesper Watchmate "Vision", which sends as well as receive.

It has a touch-screen interface on the main unit, and I have it wired up to also display targets on the chartplotter. Very handy.

The biggest thing I'd suggest is to re-think adding a second antenna. From what I've read, two VHF antennas in close proximity would likely interfere with each other (and potentially degrade performance of both AIS and VHF). Two antennas at the masthead would be problematic. Putting the second antenna on the radar mast would (presumably) put it at a much lower height the than masthead and since this stuff is mostly line-of-sight, you'd be handicapping the AIS.

I went with Vesper's dual-purpose antenna at the masthead, and ran the single coax through their splitter - which manages the conflicts between VHF signal and AIS signal. Very happy with it.

$.02
Bruce
 

toddster

Curator of Broken Parts
Blogs Author
I too went with the antenna splitter supplied by the AIS manufacturer. I have the Emtrak unit, which at the time was identical to the Raymarine unit except for the color and quite a bit less expensive. There isn’t a whole lot of government paperwork - you just need a Ship’s Station radio license, which you should have anyway if you are near the border. Oh yes, US citizens are not allowed to program their own MMSI number into their equipment. Therefore you absolutely must not use the free software download (wink wink, nudge nudge) that the rest of the world uses to do it. Otherwise, the dealer can do it or the manufacturer can mail a memory card with the relevant programming to you in about a week.
 

toddster

Curator of Broken Parts
Blogs Author
Well... ships visible to 20 miles or so, anyway. Data from more distant ships depends on being near a repeater. Probably if you are within radio range of the Coast Guard, you are near a repeater. Not sure if big ships operate as repeaters?
 

bgary

Advanced Beginner
Blogs Author
Well... ships visible to 20 miles or so, anyway. Data from more distant ships depends on being near a repeater.

I've wondered about that. I can "see" AIS targets over 100 miles away, which puts them on the far side of the Olympic Mountains... and logic says the VHF band shouldn't be able to get here from there.

Didn't know there was such a thing as an AIS repeater. Nor would the need for one have occurred to me. I mean.. past a certain point, a target sort of loses relevance from a collision-avoidance perspective....no?
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I often see ships 30-40-50 miles away when offshore. I think it must be that their antenna is very high, and mine is 60 feet or so.

I rarely see Class B boats before 5-8 miles.

[FONT=&quot]Since AIS uses the same VHF frequencies as marine VHF, it has similar radio reception capabilities which is basically line of sight. This means that the higher your VHF antenna is mounted, the greater the reception area will be. [/FONT]

[FONT=&quot]Reception from Class A vessels that are 20 or even 30 miles away on open water is not uncommon. [/FONT]

[FONT=&quot]Class B transponders use lower power for transmissions, therefore you can expect Class B vessels to be acquired when they are 5 to 7 miles away. [/FONT]

[FONT=&quot]Note that AIS has a major advantage over radar since it can see ships within radio reception range that are behind large objects, such as other ships or points of land.[/FONT]
 

woolamaloo

Member III
I eased into AIS by buying a Standard Horizon GX2200 VHF. It is a receiver only. It's currently under $320 on Amazon. My old VHF came with the boat, and while not original, it needed an upgrade. The GX2200 installed in about 20 minutes. The screw holes of the bracket even lined up with the old bracket. It used the same single VHF antenna connection as the old radio - no splitter necessary. I figured I must have done something wrong. It took me longer to read the manual than to install the radio. Boat upgrades don't go that smoothly in my experience. It worked great.

Of course, now that I had it down below, I wanted it at the helm. I bought the RAM3+ remote control/mic and mounted it by the helm for $105. It was a terrific update. So far, I've only seen ships at about the 20 mile range. I'm completely happy with it. I also registered the MMSI with the FCC. One evening I made a DSC direct hail to a Great Lakes Freighter that ignored me when I was hailing him with VHF alone.

It also has NMEA 0183 output that I'll eventually interface to my chartplotter.
 
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footrope

Contributing Partner
Blogs Author
Snip ... If I go with the AIS B (transmit and receive), I know it is important to get one of the newly approved 5 watt units rather than the 2 watt units now being sold. There is also a lot of Government tape that comes with the transmit also.

There is also the question of how big I can inflate the birthday gift.

What do you guys with the AIS feel about This?

Bob,
Did you actually find a 5 watt Class B unit for sale yet? I talked to the usual suspects at the boat show and none of the sales people were predicting when a 5 watt B type will be designed or available. I'm interested perhaps in a few years, so I haven't been looking online yet. I did hear that the Miami Boat show was where we were likely to hear a product announcement.

I like the AIS - I have a Class B. In busy ports and near marinas it is entertaining/distracting, until you get all the collision and proximity alarms silenced or turned off altogether. The info display can help you determine if the freighter a mile away is slowing, accelerating or just cruising too. DSC or Digital Selective Calling is a cool feature, if you interface to your VHF. Right out of the box on our first cruise with AIS we got an alert call on the VHF from a nearby yacht pointing out the orcas we were approaching.

You will need to apply for an FCC license for the AIS and get an International MMSI number assigned. Canada in your cruising plans(?) and all that traffic being in your front yard. To be perfectly legal you would list all the transmitting gear you have installed such as radar, VHF marine radio, HF SSB rig, EPIRB, AIS transponder. It costs a surprising amount of money, but much much less than the gear costs. The application process isn't bad at all as I recall.

With the big freighters, tugs and pilot boat traffic up there and with your 2 watts and any kind of antenna on your boat, they'll be able to see you plenty far with their high mounted antennae. By the same tricks of radio physics you'll be able to see them from plenty far away. I went with a separate antenna for the AIS, on the radar mast. If I did it again I might opt to share the antenna at the masthead. I hope you get a nice birthday present.

Edit: We have the AIS650 by Raymarine and a Standard-Horizon GX2000 marine VHF radio. The radio gets GPS from a Raymarine e7D plotter at the helm and AIS target info from the AIS650 via NMEA 0183.

Craig
 
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supersailor

Contributing Partner
The 5 watt units are just hitting the market. Milltech , Altech and others have been released. I have a friend that has a 35-2 and happens to install this kind of stuff. He says wait a short bit as there are several VHF radios that will be released very soon and they will have the 5 watt AIS built into them and they look to be very good. The problem is I like my Raymarine Ray 55 with remote at the wheel.

Christians system is interesting. In this area, most of the time is spent at the helm dodging logs, crab pots, fishermen and ships so the cabin unit is less important than the plotter display.

The antenna is an interesting problem for me. The mast connection was submerged during Terra Nova's sinking incident. I can't tell how much damage that has done. I really don't wish to pull a new cable through the mast and attempt to get it through the little hole at the bottom of the mast. I had been thinking about using a 6' high gain antenna on top of the radar mast for both. There would be a little loss due to height and some gain due to a more efficient antenna. I would be more like a powerboat and their systems seem to work very well. I would then use the mast antenna as a backup after replacing the inside part of the cable.

All boats and systems seem to be compromises. Pulling the mast to put in a VHF cable ain't going to happen soon. Testing the cable does make sense as soon as the weather gets above freezing here.
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
The Vesper unit, like all of them, will also show on the chartplotter. It's just that with my 7" helm display I just find the blips hard to see in the usual coastal clutter and to require a lot of zoom in and out.

The nav station display is out of the sunlight, requires no zoom, and my brain functions better down there. AIS provides a lot of information to process, including the second packet of destination, draft, cargo and so on. I also tend to scan through all the vessels in range, just out of curiosity and for entertainment.

At first I thought I needed a helmsman's view of the AIS stuff. Later I concluded I would rather go below and study the situation, and that there was never going to be any rush.

The Vesper is expensive, and for me the value is in the radar-like display. If a chartplotter view works, no need for it.
 

toddster

Curator of Broken Parts
Blogs Author
That’s an interesting point. The display on the Standard Horizon radios also displays nothing but AIS targets. Even the tiny display on the RAM at the helm is pretty clear. (I have the GX2000 which serves as the display unit for an external AIS.) Although I suppose that if there were more than four or five targets at once, it would get overwhelmed. I do usually glance at the display before tacking toward the navigation channel.

If buying new this year, I probably would wait for the five watt units. Or being the bottom-feeder that I am, for the flood of discarded two-watt units soon to hit EBay and the consignment stores. :egrin: Although the two-watt unit seems to work pretty well. If I flip it on in the marina, it pops up on MarineTraffic.com within a couple of minutes, and I happen to know that the nearest base station is 20 miles away and cobbled together from an old police car radio, with some significant terrain in between. Though it’s possible that the antenna is pretty high.
 
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