FA-50 Stopped Transmitting AIS Info

RickVicik

Furuno Fan
My FA-50 stopped transmitting AIS information. I became suspicious when the AIS info for my boat reported by the vessel tracking websites was older than when I last ran the boat. I bought a small AIS receiver (dAISy) that plugs into a laptop and displays AIS targets using a free software app. When close to the boat, is shows nearby boats but not mine. The FA-50 shows the same nearby boats on the TZT14.

I opened the panel covering the FA-50 and noticed that the TX LED never showed blue. It blinks orange fairly continously. According to the manual, that could mean it can't transmit because too many other vessels are transmitting. That isn't likely because in this location there are only a few nearby vessels, they are all class B and they are moored.

I noticed that the FA-50 browser screen "Sensor Status" screen was blank. The FA-50 manual seems to indicate that it should show whether internal or external GPS is being used. Does that mean it isn't getting any GPS data?

The Transponder Test and GPS Test show OK. Alarm Status shows "Nothing Data". The MMSI number in Own Vessel Data is correct. The "Silent vs. Normal" screen shows "Normal(TxRx)".

An antenna analyzer showed that the SWR on the VHF and GPS antennas used by the FA-50 was good (1.20 for VHF and 1.19 for GPS).

The most important question in solving these problem is "what changed"? Between the time it worked and when I noticed it didn't, I was testing the DSC functionality of my VHF radio and the TZT14s. The VHF radio communicates with the TZT14s via NMEA2000 while the FA-50 uses a private ethernet connection to the TZT14s, so I can't see how that could cause the problem, but who knows?
---rick
 

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Great info you provided. Based on what you have provided, I would have to say something has gone bad with the GPS antenna used by the FA-50. It is required to work for the unit to transmit. This happens sometimes if the GPS is mounted inside the radar beam or nearby RF source and the front end gets damaged. (Location mounting is important) If you have another coax antenna from another unit on the boat like a GP30,32,33,36,37 etc; you might try it with your AIS for testing. Otherwise you might want to see if you can borrow one to try. The GPS can be held by hand as long as it has clear view of the sky.
 
Thanks very much for the suggestion to try a different GPS antenna. It works fine with the temporary antenna. Also, the SensorStatus screen is no longer empty. I've attached a photo of the original GPS antenna and the radar array. The GPS antenna is on an extension tube to keep it above the radar. Do you think it is too close?
---rick
 

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If that is exactly where the old one was, then yes I think it might be a problem. I would get an extension a bit longer to get it higher.
 
Hi
My FA50 has also stopped transmitting, the internal antenna is connected but it was initially configured to use the GP330B feeding the two TZ Touch 12-2 plotters.
It just blinks the Tx Time out light almost all the time, occasionally but unpredictably coming online for a few seconds or minutes.
Any idea what would do this? The unit is 3 months old, but the same problem was experienced with three different Scitex AIS units previously, though all the antennas and wiring is new now with a proper AIS VHF antenna and the GPS antenna that came with it installed properly.
Thx
Tom Sebring SV Nomad
 
The FA50 requires its own included GPS (GPA017) be connected. It will not use an external source for transmission purposes, even if it is the GP330B or other connected items. The FA50 must have a functional coax antenna connected if you want it to transmit.
 
Hi Johnny, I've been following your help which is the best I've found online but with no success.
I took over a yacht with a FA50 which only RX very close targets. All the self diagnosis pages were ok. I installed a new high quality VHF antennae but not dedicated to AIS frequency. Still nothing. So I was advised to buy a new FA50 which I did. All the same symptoms!! I have read that you mentioned about the GPS needs to be working well? This is the only part I never changed? Do I really need a dedicated frequency antennae? Does the gps need to be GPA 017?
I dont understand how the gps will affect the RX?? Going in circles here lol. Many thanks P.S. 2 furuno dealers have looked and no help. one changed the Antennae the other used a test antennae. no one mentioned about the gps. FYI MMSI is good
 
The unit will receive but never transmit if the GPS antenna is not good. The AIS whip antenna used MUST be rated for AIS. If you use normal VHF antenna to transmit then too much reflected signal will cause problems and transmission errors. What are the lights showing on the top? Is the transmit light showing blue quickly at least every three mins?
 
Thanks for your reply

I have a strange situation. I took over this yacht last year and the AIS didn't TX and RX only about 0.5 miles. The self test was fine on all systems. An engineer changed the antenna but no change even RX!
I was told the unit must be bad so I bought a new one. Same thing!! Then reading your posts I see it could be the gps antennae? even though the self test works ok? With the new unit I even tried a stand alone new antennae (Marine VHF/AIS) and still 0.5 miles RX?
Two units doing exactly the same? So the only thing not changed is the GPS antennae but would this stop RX also?? I have ordered now a new GPA 017 so hopefully that will work and I can sell the spare unit lol. MMSI etc all ok
 
redpepps":10lgf1tv said:
Thanks for your reply

I have a strange situation. I took over this yacht last year and the AIS didn't TX and RX only about 0.5 miles. The self test was fine on all systems.

If the systems test fine, they could be working fine - however with any VHF "radio" product, antenna placement is key to increasing signal propagation. The manual stipulates the antenna can't be near any conductive material, large vertical obstructions, and must be able to "see" the horizon freely through 360 degrees. In addition, it has to be directly above or below the VHF, if it's anywhere within the same plane as another VHF than it's effectively blinded by the RF.

Review sec. 1.3 and the diagram on 1-4 of the installation manual: https://www.furunousa.com/-/media/sites ... manual.pdf

Hope this helps, :sail

- Maggy
 
Thanks for your help. Yeah I've pretty much exhausted
the antenna side. I've just ordered a new GPS antenna
to see if that helps as suggested? Fingers crossed.
 
redpepps":2y3ew8ei said:
Fingers crossed.

Bear in mind that it might take years if; let's say a radar is a few feet away and beams into a little GPS antenna, before that GPS antenna finally looses attenuation, but it most certainly and eventually will if it's getting any kind of RF interference up there. :?

It might be the second or third boat owner (by then) that has to deal with it :questions . That doesn't mean the antennas are cheap and fail every few years, rather it means a poor installation at the beginning can reduce the lifespan of the product. :cool:

If the antenna needs to be relocated, it should be. :sail

- Maggy
 
"Johnny Electron" The unit will receive but never transmit if the GPS antenna is not good.

Well Johnny you were 100% correct.
After Furuno technicians in the US and Italy changed the antennae and then the actual unit! the fault was indeed the GPS antennae!
Even though the onboard test said the GPS was ok, I purchased a new one as you recommended. Worked first time without any issues. I even connected the old unit and that also works fine!!
Many thanks to all who commented and I hope this serves to help others in the future.

:jump :jump
 
The GPS self test only tests the internal GPS sensor in the base unit; not the antenna. I am very happy you got the problem fixed. :jump :jump
 
Same problem on Karma. We’re in the Bahamas and trying to get a new GPA-017S shipped to friends arriving this Sunday but can’t find a retailer with the “S” designation in stock. What is the “S” designation? And can I do passive antenna swap without programming?
 
Conduct the programming before buying an antenna in case the antenna isn't bad. Changing the antenna doesn't require the programming but the GPS chip inside the AIS needs the newest software. The "S" means it is short cable (roughly 6-8 inches) on the antenna. If getting the GPA017 normal it comes with a 10 meter cable attached. There are other coxal antennas that can work if you can't lay hands on a GPA17 or GPA017S. You could use a GPAC01 antenna as an example.
 
I have an FA50 that was working fine with some MFD12 Plotters. I swapped out the Nn3D units For a pair of TZT16F. I can receive ais but it don't appear to be transmitting. I changed nothing about the FA50. I could previously both send and receive AIS with the MFD12s.

I suspect the GPS antenna Is original to the install of the FA50. Are these units known to go bad? Is there something about switching over to using the TZT3 displays that would cause the FA50 not to transmit? I figure it's worth asking this before I go out and buy a replacement GPA017

I should point out that when powering up the ER light comes up red for a while, and then the RX then flashes blue 3 times. Then they all go off (except the power light). RX flashes periodically. TX never lights up again.
 
Nevermind, just did the 2.02 update to the unit and it's back in action. Wish I'd found out about it needing a rollover update BEFORE I crawled into the flybridge compartment to check all the connections!
 
wkearney99":2w4tp1lp said:
Wish I'd found out about it needing a rollover update BEFORE I crawled into the flybridge compartment to check all the connections!

For what it's worth, when known issues come up there is typically a service advisory that goes out to dealers and distributors subscribed to Furuno USA's updates. The rollover issue was alerted to folks as early as August 4th, 2021.

For customers concerned about products rolling over, Furuno encourages them to contact their local Authorized Furuno dealer or contact Furuno Light Marine Technical Support and ask.

Hope this clarifies, :sail

- Maggy
 
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