AIS base station instruction to 'cease transmissions'

[MattS]

I was reading the manual for my new AIS transceiver, and I saw that one of the status is "The AIS transponder has been commanded by the local authority (via an AIS base station) to cease transmissions".

I was wondering if anyone knows why this might happen, or has seen it happen? Not a concept I'd come across before!

 

[prv]

There's all sorts of odd things in the nooks and crannies of the AIS specification, most of which seem to be rarely or never used.

Pete

 

[Buck Turgidson]

I read the ITU spec and couldn’t find any reference to cease transmissions. Sorry

 

[roaringgirl]

We had some extremely odd AIS behaviour between Lisbon and Madeira, coupled with reception of non-voice transmissions on ch16. I think it was some sort of military activity, perhaps deliberately hobbling AIS & VHF.

 

[claymore]

It'll be the Russians....

 

[MattS]

We had some extremely odd AIS behaviour between Lisbon and Madeira, coupled with reception of non-voice transmissions on ch16. I think it was some sort of military activity, perhaps deliberately hobbling AIS & VHF.

I've certainly seen reports of GPS blocking from the military - I think they occasionally put out announcements warning of 'blackout periods' for GPS (although I can't remember where I've seen these!)

 

[Martin_J]

This must be what you are referring to in the manual. The last of the reasons below...



It's just like any other bit of automatic radio transmission kit in that there needs to be a reliable/remote way of turning off transmissions.

Could this be the part in ITU-R M.1371-1 (Technical characteristics for a universal shipborne automatic identification system using time division multiple access in the VHF maritime mobile band) that covers the requirement?



Link here...
R-REC-M.1371-1-200108-S.pdf