T&T: AIS

[Peter Bennett]

Monday, December 10, 2007, 10:03:39 PM, Hans wrote:

H> Having just finished reading the latest issue of Passagemaker I am more
H> confused than before.
H> The article states that commercial "big" ships need to invest in the very
H> expensive "A" type AIS.
H> And that the "B" is not yet approved and that the "B" is not a transponder but
H> merely a receiver!

By my definition, no AIS device is a transponder - the Class A and
Class B units are transmitter/receiver devices - the transmitter
portion transmits your own vessel information, and the receiver
receives data from other vessels.  (A RACON is a transponder - it
receives a signal from a radar set, and in response automatically
transmits another signal that can be seen on the radar).

The Class B AIS units are transmitter/receiver devices like the Class
A, but transmit less information less often, and otherwise have a more
limited capability than the Class A systems used on SOLAS vessels.

H> Am I totally misinformed about this electronics piece or is the article bass
H> ackwards? I was of the impression that the "B" was receiving on two channels
H> and many of them (or all) would be transceivers, and therefore much more
H> expensive. I believe that the "A" type can be had for around $200 and the "B"
H> for $600 and up (when they go on sale).

You may be missing a "0" on the Class A price  :-)

AIS receivers are available for around $200 (single channel) - $400
(dual channel).  These are neither Class A or Class B, as they do not
transmit your vessel's data - they only receive data from other
vessels.

H> Can anybody clarify this for me?

H> Hans


-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca