EM-TRAK A100 Class A AIS for $1K at WM?!?

[KeelMe]

What do you gain by having Class A AIS?

[ronstory]

Power, update period and types of messages.

At a high level:

Class A is 12.5W transmit, Class B is 2W unless it SOTDMA then it's 5W

Class A will update every 2-10 secs based on speed and/or changing direction
Class B will update every 10 to 30 sec based only a speed - SOTDMA updates at 5 sec

Class A sends more info and you can add 'underway' info or navigational status (see post #3 for an example)

[ronstory]

I found a better table:

Ais Reporting Intervals

[mickand]

I bought the class A 'A100' primarily because I got a great price at the time.
Advantages that I have found are as follows:
Transmitting power far more than Class B.
I see towboats sometimes 20 miles away and hopefully they see me as well.
The unit transmits your position every few seconds - this can be important in 'tight' river conditions. Towboats see you almost in real time and this can be beneficial approaching sharp bends.
I see Class B targets all the time that are not where you expect them to be due to transmission lag.
You can input all sorts of info to voyage screens etc. that you can't with class B - maybe not crucial but nice to have.
Towboat captains may think they recognize you as a commercial vessel with Class A. This is not a direct advantage but often they will initialize a conversation with you to establish your status. This often makes it easier to make passing arrangements with them.

[tanglewood]

Originally Posted by mickand

I bought the class A 'A100' primarily because I got a great price at the time.
Advantages that I have found are as follows:
Transmitting power far more than Class B.
I see towboats sometimes 20 miles away and hopefully they see me as well.
The unit transmits your position every few seconds - this can be important in 'tight' river conditions. Towboats see you almost in real time and this can be beneficial approaching sharp bends.
I see Class B targets all the time that are not where you expect them to be due to transmission lag.
You can input all sorts of info to voyage screens etc. that you can't with class B - maybe not crucial but nice to have.
Towboat captains may think they recognize you as a commercial vessel with Class A. This is not a direct advantage but often they will initialize a conversation with you to establish your status. This often makes it easier to make passing arrangements with them.

Just curious. How did you get true heading to feed the AIS?

[mickand]

As previously stated, I am not well versed in how what does what - I just try to follow all installation instructions.
All my electronics are connected to a backbone including the electronic compass that controls the autopilot etc.
The A100 installation instructions state the following - "The AIS must be connected to speed over ground, course over ground, heading, rate of turn and position information sources".
The AIS junction box contains a detailed terminal block for these connections.
Again, as previously said - I have installed no other equipment to make this all work.
My Simrad chartplotter allows extension lines to be added so all targets on both chart and radar screens show heading on a dotted line extending in front of the target's direction of travel.
The product manual which includes installation instructions is very comprehensive.

[GrowleyMonster]

Class B is overall much simpler and less power hungry than Class B, which was specifically designed for yachts or other non commercial craft.

[SVPenelope]

This unit is on sale at less than $500 at WM now. There is a firmware update for the Raymarine clone that was released recently.

[GrowleyMonster]

Originally Posted by SVPenelope

This unit is on sale at less than $500 at WM now. There is a firmware update for the Raymarine clone that was released recently.

I think I paid $99 for a class B, a year or two ago. Still in the boat, uninstalled, waiting for me to get down that far on my list.