[PUP] AIS Transponder

[Ron Rogers]

On some site, I was looking at AIS signals in Seattle. USCG ships which 
appeared to be alongside their docks were transmitting on their AIS systems. 
I think that this is a tactical decision. Where safety concerns outweigh 
security concerns the AIS is on. On rare occasions like the Navy celebration 
in New York Harbor just past, I could see their turning on their AIS while 
entering and departing, but off at rest and once free of the harbor. No need 
to broadcast their positions and tactical dispositions. VHF signals can be 
picked up by ground-based stations and satellites.

Ron Rogers

----- Original Message ----- 
From: "John Ford" <johnpford@mac.com>


| Actually I have seen a large coast guard ship in the chesapeake bay
| that was transmitting AIS, it was one of the ones that work on the
| buoys.  At first it caught me completely off guard but it makes sense
| that they need to be seen when working near the shipping channels.