Hello E-gurus.
I'm getting ready soon to add AIS to our boat. I'd like to do transponder, so I can send and receive.
My current set up is two 9" Garmin 942xs MFDs next to each other at the upper helm. With GMR 18 radar. I installed them last year. I have I run the boat exclusively from the upper helm, there is a small stand alone chart plotter at the lower helm, but I'm not considering sending the signal down there. There is a 3 year old Icom VHF up there as well, which I'm not opposed to changing out (I'd likely move it to the lower helm) as it doesn't play nice with my Garmins for DSC. I'd likely move the Icom to the lower helm if I needed to get a new VHF.
I also have an easily accessible antenna mount on the side of my FB which I am no longer using.
I'd like to do this without paying an arm and a leg, and I'd install it myself.
What would you guys do?
If you can manage to install some antenna connectors and marine wiring, which it sounds like you do, I would absolutely do it yourself.
The transciever is a good idea. The cost is not that much higher, and its a good tool for others to see you. While not an end-all solution, it especially give the commercial vessels some insight into what you are up to.
IMO the standalone AIS is a good way to go; I've always been leery of AIS/VHF combined radios - I like the idea of more individualized components. I don't take advantage of DSC calls so the combo VHF is not something I care about.
I would use your existing antenna mount (assuming it will be far enough away from your other VHF antennas) and consider that there are AIS specific antennas available, tuned to the two (I think) frequencies that AIS uses, which are also in the range of a normal VHF antenna. I had an existing VHF antenna I re-purposed to a dedicated AIS antenna and it seems to be working fine; I seem to have good to excellent reception, and based on the spots I do/don't show up on MarineTraffic.com (and my distance from the receiving station) decent broadcast as well.
I have a digital yacht AiT2000 AIS transceiver. There is a newer version that has a slightly higher wattage for broadcast; the AiT2500. I chose that over the Garmin AIS simply because of the price, I'm sure it would have worked fine too. Since I was already adding the NEMO to interface my laptop, I had every reason to look at something N2K instead of staying tied to the Garmin network.
Regarding the multiplexer idea: I plugged everything I have, NMEA 0183, 2000, and a laptop on an ethernet into a Rose Point NEMO and it all just talked.... Garmin network via NMEA 2000, my ComNav autopilot via NMEA 0183, the VHF is also NMEA 0183, the AIS is NMEA 2000.... I can see my AIS targets on both of my chartplotting programs on the laptop and on my Garmins, I can run the autopilot from the laptop route course or the Garmin route course (whichever I have a course activated on). I can get the depth from the Garmin network but not the sounder or radar data onto the laptop.. I was very impressed with how easy it was to multiplex all these diverse systems with the NEMO, and also the ease of using their connectors.
I had two un-anticipated issues to deal with on on my install of the above: The antenna connection for the digital yacht AIS trancievers wants a BNC connector, and the antenna/cable I had did not have that connector so I had to source one and install it. Also, I have two Garmin chartplotters (older 4212, with the Garmin network. It turns out they had only ever been connected together with the Garmin network cable and not a N2K cable, so I had to add that to get the AIS on the second plotter (mine are one at the lower helm and one up on the flybridge.)
Other than the two cabling things above, very happy with the digital yacht AIS, it just worked from the start.