AIS..,....

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
"Nav station" down below is from the Dark Ages, you know, back when I first started sailing.
Unless you have a dual station system. Mine is ready to be installed - 9" B&G Zeus 2 at the nav station, 7" in a pod at the helm, networked.
 

nat55

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Feb 11, 2017
210
Gulfstar 1979 Gulfstar 37 BELFAST
There is also the rumored SH GX6500 which is an all in one AIS/GPS/DSC radio that has been "awaiting FCC" for 2 or 3 years now. This integrates a radio and transponder in one unit super great idea easy install... but so far not in stores. Maybe you can by it in Canada? and sneak it in.
Don't hold your breath on the GX6500, Standard Horizon has had some issues with the AIS engine and licencing but not with the FCC, it is a long story but until those issues are resolved, read contract negotiated ($$$), that model will not be made.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
You can often get good gps reception with the antenna down inside the cabin. One less hole to leak.

Les
 
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Likes: Brian D
Oct 22, 2014
21,084
CAL 35 Cruiser #21 moored EVERETT WA
My Vesper GPS antenna is in the cabin at the Nav station. Under the fiberglass deck. I get strong signal from multiple satellites. So far no issues and quick lock-in.

Note the transponder is wired to the mast located VHF antenna. I selected the tuned antenna and the powered splitter from Vesper.

I just added the SeatalkNG / NMEA 2000 link to the Vesper XB8000. This puts my depth data on my iPad and laptop navigation displays via the Vesper Wi-Fi gateway. Up to 5 connections.
 
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Likes: NYSail
Jul 11, 2018
3
Catalina 42 Herrington Harbour Marina
We have the Digital Yacht AIT 3000 and love it. Connected to our Garmin NMEA 2000 network and also wirelessly transmits AIS to iNavx on an ipad. It has a built in antenna splitter that allows it and the VHF to use the antenna at the top of the mast.

AIS provides welcome information (course, speed, closest point of approach, etc) about commercial ships around you. Really helps to see tugs and barges at night.

It is not a substitute for radar. Our experience has been that none of the commercial fisherman in our area use them and quite a number of power boaters still don't know what it is. In fog I'd want radar to know what's around me.
 
May 1, 2011
4,238
Pearson 37 Lusby MD
I have the Simrad RS35 VHF radio and the Raymarine AIS700 integrated into my N2K system so the AIS information displays on my Raymarine E90W MFD. The CPA information from AIS compliments my calibrated MK1 Mod 0 eyeballs for those pesky folks who aren't paying attention to where they're driving.
 
Sep 25, 2008
958
Macgregor & Island Packet VENTURE 25 & IP-38 NORTH EAST, MD
Since you already have a Garmin chartplotter, take a look at a Garmin vhf and their AIS transponder. Having everything from one manufacturer should insure it all plays well together and is easily connected together.
The GPSstore.com is a good place to purchase from.
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
The newer GPS units seem to be better at receiving through a fiberglass roof, compared to some of the ones from 10 or 15 years ago. The only time the performance difference of having an external antenna seems to matter these days is during stormy conditions. Sometimes the storm will attenuate the signal badly enough that the extra layer of fiberglass becomes too much. I have had a few storms where I had to bring a GPS outside to get a fix. That's just a few times, not a lot.
 
Jan 4, 2010
1,037
Farr 30 San Francisco
Has anyone come to a definitive answer over masthead vs stern rail antenna? I suspect that antenna height is more important than transmit power, specially if it is wavy. One of the things I like about the EmTrak system (assuming it works) is the splitter shares the masthead antenna with the VHF so I should see farther and transmit farther than a stern rail setup. I suppose is kinda matters what kind of RF cable you use and how tall the mast is.
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Height matters a lot. It’s a digital VHF signal. Having on the rail clearly reduces effective range.

If it’s a large ship, maybe less of an issue with it’s higher antenna. But a tug or shorter fishing boat would be less visible.
 
Oct 22, 2014
21,084
CAL 35 Cruiser #21 moored EVERETT WA
@JohnShannon You are correct. Height is important. VHF is line of sight. As such, higher lets you see farther.

Cable quality can reduce signal loss. That means more power is transmitted.
 
Jan 4, 2010
1,037
Farr 30 San Francisco
I think the bad situation is stern rail to stern rail, or stern rail to MOB then the range is poor. Big ships should have an antenna pretty high, so that stern rail to big ship probably works. With marine traffic .com you can see class B boats 25 miles away (with God's own antenna 1200' or so) So it seems 2W given the right antennas can go a long long way and line of sight is the more limiting factor practically speaking. Incidentally AIS satellites exist and cover the planet every 12 hours. Those can pick up class B boats in the middle of the Pacific that is something like 100 miles (straight up) line of sight.
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Has anyone come to a definitive answer over masthead vs stern rail antenna? I suspect that antenna height is more important than transmit power, specially if it is wavy. One of the things I like about the EmTrak system (assuming it works) is the splitter shares the masthead antenna with the VHF so I should see farther and transmit farther than a stern rail setup. I suppose is kinda matters what kind of RF cable you use and how tall the mast is.
There are two different answers here, depending if we are talking about VHF or GPS. GPS just needs to see the sky. On the rail works fine for GPS. VHF wants your antenna to see the other antenna it is talking to. With VHF, higher is much better. With VHF also consider that the long (high gain) antennas have a pancake shaped radiation pattern. They put out a beam in a wide flat pattern. If the boat is heeled over, then most of your transmit pattern is pointed into the water or up to the sky, where other VHF stations are not. In the case of a sailboat, the best VHF antenna choice is usually a short one at the top of the mast. The short antennas have more spherical radiation patterns, so they transmit evenly in all directions.
 

NYSail

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Jan 6, 2006
3,060
Beneteau 423 Mt. Sinai, NY
There are two different answers here, depending if we are talking about VHF or GPS. GPS just needs to see the sky. On the rail works fine for GPS. VHF wants your antenna to see the other antenna it is talking to. With VHF, higher is much better. With VHF also consider that the long (high gain) antennas have a pancake shaped radiation pattern. They put out a beam in a wide flat pattern. If the boat is heeled over, then most of your transmit pattern is pointed into the water or up to the sky, where other VHF stations are not. In the case of a sailboat, the best VHF antenna choice is usually a short one at the top of the mast. The short antennas have more spherical radiation patterns, so they transmit evenly in all directions.
I will be changing antenna and all cabling / fittings this winter. I hear Times Microwave LMR 400 is quality cable with limited loss. With antenna to bad they don’t have gimbled model..... same with the mast attached radar.

Again thanks for all this great info!

Greg
 
Jan 11, 2014
11,398
Sabre 362 113 Fair Haven, NY
With antenna to bad they don’t have gimbled model..... same with the mast attached radar.
There are self-leveling radar mounts: https://scanstrut.com/products/marine/self-levelling-radar-mounts

The downside to a gimbaled VHF antenna would probably outweigh the benefits. In order to stabilize the antenna, it would be necessary to have a large enough weight to dampen the motion which would add unnecessary weight to the mast head or if too light the antenna would bounce around interrupting communication.
 

Bob S

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Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
Does AIS share the same antenna as the VHF? I did a little searching here and on the Cruisers forum and it seems a lot of people are very happy with the Vesper XB8000s and less money than Garmin's AIS 800. My boat has the Garmin 7612 at the helm but it's not integrated with my Raymarine ST6001 which I learned when troubleshooting it. The Garmin chartplotter has WiFi as does the Vesper XB8000 would thy share or would there be conflict?
 
Sep 25, 2008
958
Macgregor & Island Packet VENTURE 25 & IP-38 NORTH EAST, MD
Does AIS share the same antenna as the VHF?

Depends on the AIS unit. Some do some don't. Sharing the antenna is a big plus to me, as I try to keep my "wiring" to a minimum to make tidy installations.