Troubleshooting Sitex MDA 1 Metadata Class B AIS transceiver...

[JDCAVE]

I have recently installed a Sitex MDA 1 Metadata Class B AIS transceiver. This was done as a favour and we ran out of time at the end of the day. The installer has not been able to return to work on it so I thought I'd see if anyone here can help.

It receives fine...other AIS equipped vessels are being received as before with the receive only unit (now uninstalled). The transmit part has worked intermittently, but for the most part it isn't working. I have attached a dedicated VHF antenna with no splitter. The green light is on indicating the unit is working. However, I did a radio check this afternoon and Coast Guard is not picking me up on their plotting system. They can receive class B AIS. I have NMEA 183 for the most part. Any suggestions for this Luddite?


Jim
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[MikeD]

Have you loaded your MMSI number, as my understanding (based on the Vesper unit that I have) is that it will not transmit until it has that info loaded.

 

[RT Firefly]

Greetings,
Mr. JD. Get the installer back.

 

[JDCAVE]

Yes, the MMSI and vessel name have been successfully inputed. This was confirmed by another vessel in the marina the one time it transmitted successfully. However, I read through this advice...
http://www.milltechmarine.com/Wheres-my-boat-A-troubleshooting-guide-for-Class-B-AIS_b_7.html
...and it seems, checking the system in a marina is not the best because of the low watt transmission.

Yes, I will be getting the installer back again. Hmmm! Reading the Mikltechmarine info, perhaps Class B is a WOT?


Jim
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[JDCAVE]

From Milltechmarine...
"Testing the transmission range for a vessel with a Class B transponder in a marina will not usually work. Given the low transmission power of the transponder and the interference from other metal antennas and masts from nearby boats can often mean that your transponder can't be seen even by other vessels on the same dock. Try testing out in the open water before concluding that the transponder isn't working."



Jim
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[MikeD]

Do you know if there is a marine traffic receiver nearby?

Where I boat there not many people using AIS yet, so I relied on that for confirmation following my installation. That said I had to be out on open water to get in to their coverage area, as our marina is not covered.

 

[JDCAVE]

There are a couple of other vessels in the marina that are being picked up by the marine traffic AIS system. They may be Class A, I'm not sure. I think I'm going to have to wait until I'm out on the water to be sure. Evidently marinas aren't a good place to check the operation of the unit.


Jim
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[Insequent]

My AIS works fine in marinas. Perhaps your antenna placement is an issue? You do need some separation from other antennas and other mast mounted stuff. Your manual might comment on minimum distances. Initially my ultrasonic weather station was mounted too close to the AIS antenna and that did cause issues for me.

 

[twistedtree]

To transmit, your Class B device needs to have a minimum set of info. If it worked once, then this occurred at least once, but might still be the problem.

The AIS device has it's own GPS receiver and antenna. Is the antenna hooked up correctly, and does it have a clear view?

Most AIS devices have some sort of management tool. ProAIS seems to be the most widely used. With that, can you confirm that the AIS's GPS has a valid fix and has locked onto your location correctly.

I also recall that N4712 (Oliver) had an interesting thing with his AIS where it wouldn't transmit until the boat started moving. I think once the boat had moved, the AIS would keep on transmitting even if he stopped again. But if he power cycled it, it wouldn't start up again until the boat once again moved for the first time.

 

[N4712]

Like Peter said my AIS would only TX at a stop if I didn't t cycle power. Thai problem went away once I supplied heading.

 

[JDCAVE]

Thanks people. The installer when through the computer setup and the unit checked out fine. Initially we set the unit up without the external GPS antenna. It was received by one vessel in the marina. However coast guard did not identify our vessel on their plotter. I installed an external antenna but this didn't seem to change things. The dedicated VHV antenna is well way from other antennae (>6'), and I don't see how I would be able to obtain greater separation. Its on the starboard side of the pilothouse. The VHF antenna for the radio is on the port side and is considerably higher with an extension. There is a forestay on the pilothouse roof, an Airmar weather station, forward on the roof and a GPS mushroom antenna, again well forward on the PH roof.

I'm going to take the vessel out later this week and see how it performs. I think we might find that it will work better when we are moving.

 

[N4712]

Thanks people. The installer when through the computer setup and the unit checked out fine. Initially we set the unit up without the external GPS antenna. It was received by one vessel in the marina. However coast guard did not identify our vessel on their plotter. I installed an external antenna but this didn't seem to change things. The dedicated VHV antenna is well way from other antennae (>6'), and I don't see how I would be able to obtain greater separation. Its on the starboard side of the pilothouse. The VHF antenna for the radio is on the port side and is considerably higher with an extension. There is a forestay on the pilothouse roof, an Airmar weather station, forward on the roof and a GPS mushroom antenna, again well forward on the PH roof.

I'm going to take the vessel out later this week and see how it performs. I think we might find that it will work better when we are moving.

I wouldn't worry about it, as long as the GPS isnt direct next to the antenna you'll be fine (I mean inches away). My AIS GPS antenna is mounted under my FB brow and shoots through the FB no problem. They'res also a VHF antenna about 5ft away on the other side of the glass.

 

[JDCAVE]

I wouldn't worry about it, as long as the GPS isnt direct next to the antenna you'll be fine (I mean inches away). My AIS GPS antenna is mounted under my FB brow and shoots through the FB no problem. They'res also a VHF antenna about 5ft away on the other side of the glass.

Thanks Oliver!


Jim
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[JDCAVE]

Unit still isn't working. Tried it on the main VHF antenna, which we know works and still no good. It receives, computer diagnostics says it's getting a fix and is transmitting but nobody is receiving our signal, including VTS. Swapped in a new unit and still isn't working. Electrician is at a loss. Suggests I consider the Garmin product. Sigh! Any ideas?

Jim
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[Insequent]

Still seems to me that antenna interference is a prime suspect. Borrow a different brand from a friend who can demonstrate transmission with it on their own boat. Do a temporary install of it on your boat in a similar position to the Sitex. Test for transmission.

Also, do a temporary install of your Sitex unit on your friends boat and test for transmission.

That should isolate or eliminate antenna location or installation problems, and may well confirm your Sitex is working OK.

 

[JDCAVE]

We've tried both antennae on the boat. One is a big long extended one for the VFH and it works fine for the VHF. You've got to put an a antenna somewhere and there's limited options after a point. I just don't think this should be this hard.


Jim
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[JDCAVE]

This is the best photo of my VHF antennae. The AIS antenna is located on the Stbd side.

The small antenna is the Bad Boy WIFI antenna. To emphasize, neither of the VHF type antennae work with the AIS.


Jim
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[twistedtree]

Sorry if this had already been covered..... But it sounds like something silly and simple.....

Has the MMSI and other boat vital data been programmed? devices I'm familiar with won't transmit if these things aren't programmed.

Also, is it possible that the "silent" input (assuming it has one) is activated?

Can you tune your VHF to the AIS channel and listen to see if you here squeaking coincident with the transmit light on the unit? Or maybe there is some other way to test whether it's actually transmitting over the VHF band?

 

[JDCAVE]

No. It's been programmed. Silent mode has not been configure door this unit. It's optional an is not enabled.The electrician says he's a installed several of the Garmin units and no problems.


Jim
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[JDCAVE]

TT: I think I'm kinda at the stage you were with the Simrad. A lot of work has gone into this and I've bought a GPS antenna and tested a whole bunch of stuff. I'm blowed if I'm going to start buggering around buying antennae and the like just to throw poop on the walls to see what sticks. I'll phone tech support tomorrow again and see if I can get further with it.

I had heard that another user had issues and it ended up being an intermittent issue with power. I just don't think the unit is putting out enough HUMMMFFF to send a signal...but who am I to know.


Jim
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[twistedtree]

I hear you. We buy products to serve us, not for us to be slaves to them. My new rule us that I'll spend no more than one session with tech support trying to get something to work. If it's not working after that, I just return it and get something else. Poor products should be their problem, not yours.

 

[JDCAVE]

Okay...so... I think I may have solved the Sitex AIS problem. The tech at so-tex and the electronic rep in Seattle think the antenna is the problem. So I've hooked it up to the long VHF antenna again that I know works well with the VHF. I am now showing up on one of the local ships antenna. Diagnostics indicate a VSWR of 0.9:1. Diagnostics of the other antenna indicates a VSWR of 3.8:1. Technician at Sitex things that isn't adequate. I bought a Shakespeare 5225-xt antenna which was was recommended by the Seattle rep. Will see how that develops over the next couple of days.


Jim
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[twistedtree]

I had a similar issue in the past and found the problem with an SWR meter. They are not very expensive, and very handy to have around for testing such things.

I think chances are that your problem is in the connector(s), not the antenna itself. If you are using solderless connectors, that would be my first guess. I have not had good luck with them. Carefully prepping and soldering on a PL-259 connector is a total pain in the butt, but very much worth it in the long run.

 

[JDCAVE]

I had a similar issue in the past and found the problem with an SWR meter. They are not very expensive, and very handy to have around for testing such things.

I think chances are that your problem is in the connector(s), not the antenna itself. If you are using solderless connectors, that would be my first guess. I have not had good luck with them. Carefully prepping and soldering on a PL-259 connector is a total pain in the butt, but very much worth it in the long run.

Thanks TT. I was just going to ask about the solderless connectors:

http://shakespeare-ce.com/marine/product/style-pl-259-cp-g-connector/

So...the antenna. I bought a new one but have not yet installed it. I'm having a devil of a time getting an electrician on board to help. They are too busy doing larger projects at this time of the year.


Jim
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[JDCAVE]

Another update. As mentioned, I bought a Shakespeare 5225-xt antenna which was was recommended by the Seattle rep. I bought this before carefully inspecting the one I have installed. It turns out I have a nearly identical antenna, with the blue and green band on it. No manufacturer's name but it is in all other respects it is identical.

Another electronics fellow came aboard and looked at my diagnostics again. Everything checks out fine with the AIS connected to the big 16' antenna. He said the easiest way to determine if the 8' Shakespeare is working would be to connect it to the VHF and test it. I contacted coast guard on the working channel for a radio check on a 1watt transmission and he indicates a strong transmission to Bowen island.

So, I'm damned if I'm going to swap out a perfectly good antenna for another identical one, just for a chance that this fixes the problem. So I'm taking the new antenna back, unused.

So we're going off on our long trip tomorrow, providing the weather cooperates. We will leave the AIS connected to the taller antenna, and the radio on the shorter one, which is probably 18 feet above the water. We will see how that works. If anyone sees "Phoenix Hunter" on AIS, be sure to say hello!


Jim
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[Tolly Roger]

Another way of testing

Within marine traffic.com you can set up known vessels in "My Fleet".
In that set up you can have the system eMail you when one of your fleet becomes "in range" of any of the sites stations.

If you set up your own boat in your fleet it will send you an email that you are "under way" or "in range" and thus confirming you are sending an AIS signal. You know it's working !!! ( You will need to be within cel phone/wifi range )

Tracking a friend's boat in your fleet is another (albeit kinda creepy) way of knowing where they are.

As a side benefit if you get an email that YOUR boat is under way and your out mowing the lawn you may want to take some kind of alternate action!!!

 

[JDCAVE]

Thanks, Tolly.

I was talked into keeping the 5225-xt antenna and I've installed it. Diagnostics are checking out fine on the proAIS2. VSWR is 2.2:1. Voltage is 12.7. Silent mode is not hooked up. We continue to receive AIS targets and these display on the plotter but we are still not able to transceive. I contacted Vessel Traffic Services on 74A and they are not identifying us after 45 minutes. We are not showing up on Marinetraffic.com.


Jim
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[twistedtree]

It seems there is not much left at this point other than a bum AIS device, right?

 

[JDCAVE]

It seems there is not much left at this point other than a bum AIS device, right?

Yup. It may get started when we move about. Not sure. The vendor says he will accept a return when we get back in 3 months. I'm at a loss.


Jim
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[JDCAVE]

We left Steveston for Pender Harbour on Wednesday. AIS started transceiving and showed up on Vessel Finder. At some point we were out of range from the shore based stations and our progress was no longer updated. We didn't check with any vessels in the water to see if they could see us on their display.

6 weeks ago, we went out on the water and the unit was not transceiving, so perhaps the upgrade in the antenna has made a difference.

Jim
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