AIS transmitter or Radar Enhancer?

[Mistroma]

I take it that this is all speculation as you didn't put in a link to any rule or regulation.
What you describe is apposite to DSC VHF, nothing to do with the subject under discussion - AIS Tx
As much as some people like DSC, I don't, so even if I were to install a DSC capable VHF, I wouldn't request or program the set with an MMSI #
so to put out an MMSI # on AIS is pointless.
I only suggest putting NO in the AIS MMSI field as a possibility, my personal inclination would be to leave it blank.

I don't think that it is speculation. The ITU Radio Regulations (and US FCC) require vessel owners to obtain an MMSI prior to using Class A or Class B AIS. Class B AIS transponders will not function if an MMSI number has not been programed into the transponder's system.

It is covered in lots of places but following 2 docments should be adequate.

DATA ELEMENTS FOR ELECTRONIC SUBMISSION
MMSI is a mandatory AIS field (Mentioned elsewhere that the format must conform to ITU standards)
http://www.itu.int/ITU-R/terrestrial/docs/mars/AtoN/aton-electronic-notif-en.pdf

OR
M.1371 : Technical characteristics for an automatic identification system using time-division multiple access in the VHF maritime mobile band
https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.1371-5-201402-I!!PDF-E.pdf

Extract below

3 Identification
For the purpose of identification, the appropriate maritime identities should be used, as defined in Article 19 of the Radio Regulations (RR) and Recommendation ITU-R M.585. Recommendation ITU-R M.1080 should not be applied with respect to the 10th digit (least significant digit). AIS stations should only transmit if an appropriate maritime mobile service identity (MMSI) or unique identifier is programmed.

Sorry, above already covered by others. I obviously forgot to refresh the page before replying and didn't see the other replies.

 

[RichardS]

With my Vespermarine AIS unless you insert an MMSI number all the transmit parameters are greyed-out and you cannot do anything but receive.

I have used two different MMSI number in my transceiver, first a Croatian number and then a British number, and both were accepted so I'm guessing that you could put in any number with the correct number of digits although it might not accept the first 3 digits if they are not one of the approved country codes.

However, as others have said, it so easy to register and get a valid number I can't imagine why anyone would not want to.

Richard

 

[wiggy]

Id definitely go AIS Transeiver. Anyone come across this company https://em-trak.com/ the CLASS B : AIS B100 seems to do everything at a much lower cost than others I've found. I'm thinking of replacing my NASA AIS receiver that plots to Standard Horizon plotter.
Any thoughts or alternatives.
Oh forgot to say sorry for the hijacking.

 

[LadyInBed]

You don't know much about AIS, do you? Check out this link https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.1371-5-201402-I!!PDF-E.pdf and read para 3.

Obviously not.
Looked at the link and what others have written above, especially what RichardS said, which makes my suggestion of putting NO in the field or leaving it blank null and void.

 

[doug748]

....
Any thoughts or alternatives.
Oh forgot to say sorry for the hijacking.

Feel free to hijack. I am still lurking in the background and taking everything in.

I nearly bid on this, the newer Vesper:

http://www.ebay.co.uk/itm/322024364621?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Looks like it could be a direct replacement for your NASA with built in GPS and an excellent display. They normally retail at c £700

 

[LadyInBed]

I don't understand the objection to DSC VHF either - you don't have to use the calling functions if you don't want to but the digital mayday function alone is worth having

Nothing to do with calling functions, I just don't want to spend time cancelling alarms, though in fairness I understand that the frequency of alarms has reduced over the years.
Though on present form, I might be wrong about that as well

 

[prv]

I take it that this is all speculation as you didn't put in a link to any rule or regulation.

It's nothing to do with rules or regulations, it's a simple technical fact. Like trying to connect a device to the Internet but saying "I don't believe in IP addresses so I'm not going to have one".

What you describe is apposite to DSC VHF, nothing to do with the subject under discussion - AIS Tx

It's one thing to be wrong, but do you need to be quite so aggressively wrong?

to put out an MMSI # on AIS is pointless.

To transmit AIS messages without an MMSI is not technically possible.

Pete

 

[LadyInBed]

It's nothing to do with rules or regulations, it's a simple technical fact. Like trying to connect a device to the Internet but saying "I don't believe in IP addresses so I'm not going to have one".

If it isn't clear in #44, I totally accept that I was wrong

It's one thing to be wrong, but do you need to be quite so aggressively wrong?

I've accepted that I was wrong, but I hope that I don't post aggressively!

 

[Bru]

Nothing to do with calling functions, I just don't want to spend time cancelling alarms, though in fairness I understand that the frequency of alarms has reduced over the years.
Though on present form, I might be wrong about that as well

Ah, I understand where you're coming from then

However, I can't say that in the five years I've been pottering around with a DSC radio on that the alarms have ever been onerous or irritating

The one irritation I do have with the current Icom unit on Erbas is the useless display of the incoming DSC alert but other more modern units are much better

I certainly don't find the occasional DSC alert a sufficient annoyance to outweigh the benefits of the DSC Mayday facility

 

[DJE]

Just checked the ship station database and it seems that we do have an MMSI. It must have been allocated when SWMBO was sorting out the change of ownership. I hadn't realised the significance of the MMSI to AIS - thanks all.

 

[Lifeboater]

I'm not convinced that a yacht running into you necessarily would be the end of your world, whereas a ship running into you might seriously spoil your day! So the active radar enhancer is surely a safer bet?

The real danger for a smallish yacht is from fishing boats, as the bow wave from a merchant vessel will boot you to one side. Alas after the crew are washed overboard, the mast often hits the hull and then clobbers anyone who did not dive below decks. A fishing boat collision can easily send your pride and joy down to Davey Jones. The other big issue is that trawler skippers keep chasing fish finder returns, so zig zag all over the place, even with a radar they are a menace in poor vis.

My little Rowan 22 is a tad too small for a radar and no room in the aft cabin for the display. So I'm planning on fitting an Echomax if that is all that's available.

 

[RivalRedwing]

this is an old thread, has the assembled view changed with rapid expansion of AIS transponders (and receivers) ?

 

[Lifeboater]

this is an old thread, has the assembled view changed with rapid expansion of AIS transponders (and receivers) ?

Most yachts seem to have an AIS receiver, but as a previous post pointed out, AIS transponders are expensive and use more power. I've got a basic AIS receiver and plan to fit a radar image enhancer. Radar reflectors are not very effective unless they are very large and mounted high up. Not practical for a small yacht.

 

[wonkywinch]

Most yachts seem to have an AIS receiver, but as a previous post pointed out, AIS transponders are expensive and use more power. I've got a basic AIS receiver and plan to fit a radar image enhancer. Radar reflectors are not very effective unless they are very large and mounted high up. Not practical for a small yacht.

Although the thread is old, thank you for revitalising it as it's a topic I'm currently looking at.

I've got radar and an AIS transponder and as I gain experience on the water, my limited experience has shown fishing vessels are a major hazard because many turn off their AIS when they are fishing presumably to keep secret from their competitors.

Crossing Lyme Bay last year, one called me on the radio, we chatted about intentions and he passed by my stern. 10 minutes later they had zig zagged and now presented a collision risk again. Thank goodness the viz was good that day.

 

[Roberto]

this is an old thread, has the assembled view changed with rapid expansion of AIS transponders (and receivers) ?

Have had both (ais txr and radar enhancer) >10y, if I had to choose one electronic aid to:
a. Be seen: offshore I'd prefer the RTE any time, if coastal the AIS.
b. See others: though not included in this thread, to me it's radar above anything else, anywhere; sticking to the topic, offshore again the RTE -it simply detects more ships, believing "all ships send AIS" is an illusion; AIS is very helpful when crossing traffic lanes, when there are more than 3-4 crossing targets at widely different speeds I cannot track them even on radar, sometimes one concentrates in closer ships while there are others behind with speed vectors making them more risky, or when they take avoiding action between themselves, ais can be very helpful in giving hints as to what might be going on. While coastal sailing in normal visibility the contribution of electronic devices to a visual watch is imho very limited.

 

[Lifeboater]

Last time around I had a Furono 1621 and it failed twice, the first time was a blown magnetron that was repaired under warranty in Fiji, the second was also a blown magnetron near South Africa, BUT, when the local expert checked the set in Cape Town, he showed me on an oscilloscope that the driver board voltage was spiking out of limits and that was why the magnetrons were failing. The set was just out of warranty and the cost of a new magnetron plus driver board was the same as a new radar. So if you buy a radar, just make sure the warranty is not just one year. Furuno were not interested in the fact the driver board defect should have been detected when the first failure occured, so I gave up and sailed the rest of the way from Cape Town direct to Gran Canaria via a stop in St Helena, (Very nice), and Cape Verde Islands, (Not the best of places apart from Isle Du Sal).

 

[dom]

It's nothing to do with rules or regulations, it's a simple technical fact. Like trying to connect a device to the Internet but saying "I don't believe in IP addresses so I'm not going to have one".



It's one thing to be wrong, but do you need to be quite so aggressively wrong?



To transmit AIS messages without an MMSI is not technically possible.

Pete

 

[Muddy32]

I find that keeping a good visual watch is the best way to avoid a collision. That coupled with an early, large [20+deg] avoids any confusion with commercial shipping. Fishing boats are a different kettle of F****.

 

[Lifeboater]

I find that keeping a good visual watch is the best way to avoid a collision. That coupled with an early, large [20+deg] avoids any confusion with commercial shipping. Fishing boats are a different kettle of F****.

So WTF do you do in thick fog, or heavy rain ???

 

[Muddy32]

Do not cross the Channel and await better weather. Just like we used to.