Ais transmit left 'on'

Robin · 1 Apr 2014

I JUst discovered that on our Garmin network, the AIS transponder gets it's power from the NMEA 2000 backbone cable if the main panel switch is on and this is irrespective of the plotter display or other instruments being turned on or off. IN order to stop the continuous transmission of AIS data it is necessary to switch off the main power to the NMEA 2000 backbone connection cables, simply shutting off the plotter and AIS display only affects receipt of data from other vessels. We can receive and display only and without transmitting ourselves by switching on the separate AIS 'Silent' switch we had installed. Of course switching off all 12V power on the battery master switches will turn everything off including the AIS transponder.

This might just explain why some boats are seen to be transmitting 24/7,as their owners may well think their AIS is turned off when in fact it isn't. We routinely switch off all battery master switches on leaving the boat and should therefore not leave things 'on' inadvertently, but then I'm a smug git...

Twister_Ken · 1 Apr 2014

Robin said:
but then I'm a smug git...

Surely not!

lustyd · 2 Apr 2014

Surely it shouldn't be a shock that your AIS transponder, like your VHF bypass switching in order to maintain safety equipment availability at all times? Or did you just buy the AIS as a toy

single · 2 Apr 2014

There are a few around here that are on 24/7 and one of them the boat hasn't moved for years. Surely the owners must look at AIS or know its on? Maybe its a security thing. Look at the one on marinetraffic up the river Wye, its always on.

Sandy · 2 Apr 2014

Given that Trinity House and Northern Lighthouse Board are installing more as an aid to navigation, pehaps the owners are doing the same.

Robin · 2 Apr 2014

lustyd said:
Surely it shouldn't be a shock that your AIS transponder, like your VHF bypass switching in order to maintain safety equipment availability at all times? Or did you just buy the AIS as a toy

I'm not smartarse enough to realise the blindingly obvious but yes it came as a surprise that with all my instruments(radar, plotter, VHF, wind/boatspeed display and autopilot) all turned off that the AIS was still transmitting just as long as the interlinking NMEA200 cabling was getting power from the main 12V panel breaker. Presumably by the same token the windspeed transducer is still receiving power as is the triducer (depth/temp/boatspeed). THE VHF is definitely 'OFF' when switched off at the set, although it can be turned on again via the RAM microphone handset out in the cockpit.

YES of course my AIS is a toy along with everything else on the boat

Robin · 2 Apr 2014

single said:
There are a few around here that are on 24/7 and one of them the boat hasn't moved for years. Surely the owners must look at AIS or know its on? Maybe its a security thing. Look at the one on marinetraffic up the river Wye, its always on.

it is the same here too, but be aware that if you look on marine traffic or similar sites they may be displaying 'old' information, just look at the time it says the last data was received. If I search for my boat it still shows up from it's last transmission even though (NOW) it definitely is 'off as the main battery power breakers are all off. search for Roxanne (US registered with MMSI 367600840) and you may see it but it will be data it transmitted yesterday when I was on board and the indtruments were powered up. see herehttp://www.marinetraffic.com/en/ais/details/ships/367600840/_:e24403605fc692b8bf05d35e66a6ea55

single · 2 Apr 2014

Robin said:
it is the same here too, but be aware that if you look on marine traffic or similar sites they may be displaying 'old' information, just look at the time it says the last data was received. If I search for my boat it still shows up from it's last transmission even though (NOW) it definitely is 'off as the main battery power breakers are all off. search for Roxanne (US registered with MMSI 367600840) and you may see it but it will be data it transmitted yesterday when I was on board and the indtruments were powered up. see herehttp://www.marinetraffic.com/en/ais/details/ships/367600840/_:e24403605fc692b8bf05d35e66a6ea55

Yeah, but it only shows info for a few hours after you switch it off, then vanishes.Imagine the mess if all of us left them switched on

Colvic Watson · 2 Apr 2014

I moaned for a couple of years about those who left transponders on - then I bought one - always on when we're on the boat; too much trouble to drill down menus to find the off bit.

single · 2 Apr 2014

Lazy Kipper said:
I moaned for a couple of years about those who left transponders on - then I bought one - always on when we're on the boat; too much trouble to drill down menus to find the off bit.

I like it when certain ones are on, i know which friends are where

Robin · 2 Apr 2014

Lazy Kipper said:
I moaned for a couple of years about those who left transponders on - then I bought one - always on when we're on the boat; too much trouble to drill down menus to find the off bit.

Me too but you cannot stop ours off from transmitting from within the menus at all, all you can do is stop it displaying other vessel data on the chart or the radar screens, it is still transmitting own boat data unless as in our case you have a specific transmit off or 'AIS Silent' switch or you turn off the power supply. on our Garmin set the 'AIS Silent' switch is a simple toggle switch wired between two specified cables coming from the black box.

Colvic Watson · 2 Apr 2014

single said:
I like it when certain ones are on, i know which friends are where

If you can see ours then it means the boat's been nicked.

nigelmercier · 2 Apr 2014

Robin said:
YES of course my AIS is a toy along with everything else on the boat

ille quis mortem cum maximus ludos, vincat

Robin · 2 Apr 2014

nigelmercier said:
ille quis mortem cum maximus ludos, vincat

We all like our toys, not ready to peg it yet though I hope and they might help delay that day if used intelligently.

david_bagshaw · 2 Apr 2014

single said:
There are a few around here that are on 24/7 and one of them the boat hasn't moved for years. Surely the owners must look at AIS or know its on? Maybe its a security thing. Look at the one on marinetraffic up the river Wye, its always on.

seem to remember that one is a position by e mail report, and not a transmitter on all the time. Otherwise it must have an outstanding transmitter, in view of where their receivers are positioned.

Robin · 2 Apr 2014

david_bagshaw said:
seem to remember that one is a position by e mail report, and not a transmitter on all the time. Otherwise it must have an outstanding transmitter, in view of where their receivers are positioned.

Not sure what you mean. As I understand it there are some land stations issued with freebie receivers in locations where they have a good reception likely, as in high ground overlooking clear waterway or ocean and these send the data automatically to onlinecompanies such as Marine Traffic and Vessel Finder, another that I look at online, these companies post the received data on their websites for sad gits like us to look at.

single · 3 Apr 2014

david_bagshaw said:
seem to remember that one is a position by e mail report, and not a transmitter on all the time. Otherwise it must have an outstanding transmitter, in view of where their receivers are positioned.

True, i can't imagine it would transmit from that far inland up a valley.Unless he is using 'boatbeacon'?

View attachment 41219

Robin · 3 Apr 2014

single said:
True, i can't imagine it would transmit from that far inland up a valley.Unless he is using 'boatbeacon'?

View attachment 41219

VHF line of sight transmission and favourable atmospherics maybe, but they do have and show AIS positions mid-ocean from satellites, maybe it was satellite reception. We sometimes here 'see' on our AIS set, vessels going at high speed up interstate I-95 I don't think they are stopping off to e-mail in their locations but have left the transmitter running and at various spots along the way their data transmission is received. I think data transmissions travel farther than voice does over VHF which was why we could routinely and irritatingly receive DSC alarms on our boat in Poole from Joburg Traffic Control in France, over 65miles away. and when in out at sea the Channel receive them from French Coastguards several hundred miles away in southern Brittany, mostly all of that distance over land too.

david_bagshaw · 3 Apr 2014

On interrogation of the v[FONT=arial, helvetica, sans-serif]e[/FONT]ssel there is the line

59 minutes ago
(AIS Source: 888Self Report)

where as a normal plot says something similar to
Received:
1 minute ago
(AIS Source: 1035JC/MC)

this page explains how to do an e mail report

http://www.marinetraffic.com/en/p/expand-coverage#12

Robin · 3 Apr 2014

jeez life is too complicated already to want to give a position any wayother than from the AIS transmitter, let alone having yet another 'app on the phone or remembering to send in an hourly email. .

Ais transmit left 'on'

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