AIS Class B who’s got it?

[pescador]

Thinking about installing Garmin AIS800 on the boat. I had class A in the previous boat but think class B would be better safety wise. Looks easy enough to install. Power cable, NMEA drop cable, vhf input and output to radio and that’s it. Anyone using it? Thought? I see that some other manufacturers have a 2 watt versus a 5 watt output. How significant is this? Also sounds like having the option to use the existing vhf radio antennae and internal gps antennae are important as not all manufacturers offer this where the higher end units all seem to. Lastly, on Amazon there are some dirt cheap knock-offs. 1/3 of the cost of the Garmin….tempting but I just worry about accuracy.

 

[Flashman]

I use this one, the 5w with splitter.

B900 - em-trak

The B900 series delivers market-leading AIS performance in a compact, rugged design. It is lightweight, durable, and easy to find and install, with reliable connectivity to keep you visible, informed and in control.

em-trak.com

Class B (2W) will only transmit a position update every 30 seconds. Class B+ transmit at varying intervals based on vessel speed. The faster you go, the more frequent the position updates. I would recommend B+ (5W) for this reason alone. Most of us can travel fairly far in 30 seconds.

There is a difference in transmitting time slop coordination with other AIS units in the area. All AIS transmitters talk to each other when within range. They coordinate themselves into transmit time slots so they don't interfere with each others position update signals. From what I understand it's possible for a Class A unit to bump a class B out of it's intended transmit slot thereby causing the class B unit to wait an additional 30 seconds before updating. It's a low probability event, but for a little extra why not get the better one? The class B+ has the same transmit priority as the class A so won't get bumped.

 

[pescador]

I use this one, the 5w with splitter.

B900 - em-trak

The B900 series delivers market-leading AIS performance in a compact, rugged design. It is lightweight, durable, and easy to find and install, with reliable connectivity to keep you visible, informed and in control.

em-trak.com

Class B (2W) will only transmit a position update every 30 seconds. Class B+ transmit at varying intervals based on vessel speed. The faster you go, the more frequent the position updates. I would recommend B+ (5W) for this reason alone. Most of us can travel fairly far in 30 seconds.

There is a difference in transmitting time slop coordination with other AIS units in the area. All AIS transmitters talk to each other when within range. They coordinate themselves into transmit time slots so they don't interfere with each others position update signals. From what I understand it's possible for a Class A unit to bump a class B out of it's intended transmit slot thereby causing the class B unit to wait an additional 30 seconds before updating. It's a low probability event, but for a little extra why not get the better one? The class B+ has the same transmit priority as the class A so won't get bumped.

I’ve looked at the em track as well. It looks good. What do the wifi and Bluetooth options do?

 

[Flashman]

You have to enter some data when you set it up the first time. Saves having to plug it into a computer by USB. Might be some other advantages but I can't remember them if there are. I set mine up a few years ago.