FA-50 Stopped Transmitting AIS Info

[BAW]

I have a FA50 AIS that not wants to transmit (TX).
The SW update has been carried out (2.02) with HUB and PC. Behave as described in a downloaded description.
Still the AIS is not transmitting.

Checking the Webb interface Tx/Rx or silent with Rx works.
We revive all AIS data from other boats (their Tx to our Rx).
I have bean reading some posts ther they talk about GPS miss functions to transmit? Due to GPS ?
Correct me if I’m wrong:
GPS for position (no Tx/Rx)
Rx listen on the VHF band
Tx to transmitt on the VHF band
Class B 2w
Class A xx w and more frequent update
Right know the AIS on its own RF antenna 10-15 m separation from VHF radio

Out boat name etc has been edited by MacOS. But update done via ECS-3000 and Win 10 PRO.
Regards Bernt-Åke

 

[Johnny Electron]

The GPS antenna is needed for the FA50 clock/sync and the unit will not transmit without a good working coaxial antenna, even if you wire a secondary source. If you are running the newest software and are not in silent mode, and your tx light is flashing yellow; the GPS antenna is most likely the problem. Bad AIS whip antenna or cable will normally result in a RED tx light.

 

[BAW]

Tested two diffrent GPS antennas, one the GPA-017S and one external mounted on the antenna mast (both Furuno GPS antennas). Both gives perfect positions, the VHF antenna placed at same mast (the lower one which are are combined with Furuno PC radar, 4G unit (mobile and WiFi), two GPS antennas and VHF antenna (Furuno).
Design by Furuno Sweden.
The third GPS was installed inside our boat (GPA—17S).
Have removed the “old” Navtex unit.
I can’t really understand why a antenna can revive VHF info (Rx), but not transmit (Tx) om same unit (antenna).

The Tx time out? Time out of what?
Could test the GPS-17s with short cable. but since all other info working this make no sence!
The Tx light can not illuminate RED! Only on start up phase are you getting RED light, then it moves flashing on Tx/rx , a short blue then flashing.
As user how can you see what SW release the AIS running on?

Bernt-Åke

 

[wkearney99]

I can’t really understand why a antenna can revive VHF info (Rx), but not transmit (Tx) om same unit (antenna).

From what I understand the FA-50 does transmit and receive on it's own VHF antenna. It's requires it's own so the transmitting power of your VHF radio doesn't cause front-end overload and fry the receiver in the FA-50. That and with it's own antenna it's guaranteed to be able to continue to send/receive AIS regardless of whether you're transmitting on your VHF or not.

 

[Johnny Electron]

The whip antenna does receive the AIS targets and also transmits your infomation. The GPS is diffrent and has diffrent function for clocking/syncing and obtaining your position to include in your transmission. They are not the same. Be careful on terminology. While AIS can use a VHF whip to receive on receive only units, VHF whips can NOT be used on transponders that transmit. To transmit you need an AIS whip or a whip rated for both VHF and AIS. Using a VHF whip on a transponder will create reflected signal which can burn up your transponder. Normally if there is a problem the ERROR light will light RED, if getting this.

 

[Magnetron]

Separate antennas on the boat is best.

One for GPS, one for VHF and one true AIS antenna. The GPS antenna is tuned to 1575.42 Mhz and/or 1227.60 MHz, the AIS antenna is tuned to the AIS frequency of 162 MHz. The VHF antennas are tuned to 156.8 MHz. Sure some of these frequencies are close, but the antenna tuned to the specific frequency is going to be much more receptive for that sensor than the others would be for the same application.

Both Furuno, and Shakespeare, do not recommend using splitters even though they exist, rather the safest deployment is using independent antennas instead, especially when it comes to VHF communication.

VHF has saved more lives at sea than any other safety equipment, with exception of maybe the PFD.

Hope this clarifies, :sail

- Maggy

 

[Neildeb2]

MY FA-50 has always received great (displays on my NavNet 3D MFDBB Black Box system). But it never transmits.
1. It uses a dedicated Shakespeare 8' AIS antenna.
2. The blue "transmit" light flashes every 90 seconds to say it's transmitting.
3. It is fully updated as of June 2022;
4. I sent it and the GPS antenna to Furuno for testing and got it back last week; no problems found except they said it was in Silent mode. (I asked, but no one could explain why was it flashing the blue xmit light every 90 seconds?)
5. I reinstalled it today. Receives great, no error lights, blue xmit light flashes every 90 seconds. But it is not transmitting. The USCG, other boats, marine traffic.com - all of them say they don't see me.

I connected the AIS to a hub and the hub to the MFDBB. It recognizes the FA-50, and I can open the menu and manipulate the sub-menus (though I can't figure out how to enter letters for login/password via the control panel).

The antenna and cable HAVE to be ok, right? It's receiving perfectly.

I'm really frustrated! Where do I go next? Any ideas? Thanks.

 

[Johnny Electron]

2. The blue "transmit" light flashes every 90 seconds to say it's transmitting.

If you get a blue transmit light you ARE transmitting. Depending how it is mounted on the boat maybe you have something blocking the range. If you had the blue light, not sure why anyone would question the GPS antenna because you won't get a blue light without a working GPS antenna connected. Keep in mind Marine traffic first off is delayed by at least 20min. You also must be in range of a volunteer site to pick your signal up. The range transmission range in real world on a class B like the FA50 is 5 nm. People are not going to hit you 5nm away. I would recommend getting someone parked next to your boat to check their AIS. Keep in mind if they have an old AIS system before 2009, it might not show Class B boat names. That is a problem with their unit not yours. Even if they have an old unit; they should see your MMSI because it goes out under a class A message. I have NEVER seen a FA50 with a working blue transmit light not work. I think you need better verification/test. If you doubt the output, it can always be sent in and they can put a watt meter on it.

 

[wkearney99]

1. It uses a dedicated Shakespeare 8' AIS antenna.

Which antenna? It would seem unlikely that it would be able to receive AIS and not be able to transmit, but as was pointed out a few posts back, VHF for marine radio and AIS are on different RF frequencies. Couldn't hurt the check which antenna you've got.

 

[wkearney99]

If you doubt the output, it can always be sent in and they can put a watt meter on it.

It would appear the unit was already sent back for diagnosis?

4. I sent it and the GPS antenna to Furuno for testing and got it back last week; no problems found except they said it was in Silent mode.

I'd hope doing an output test would have been part of that repair process, right?

I wonder about the 'silent mode' observation. Isn't that determined only by a contact closure switch? Wouldn't a bare unit sent in for diagnosis not be able to activate being in 'silent mode' without a switch wired up for it?

 

[Johnny Electron]

Good points. I missed that the unit was also tested. I can't see how it isn't working. Silent mode would put the TX light into a flashing yellow the same as a bad GPS antenna. I guess with all that said, if you feel there is a problem a dealer would need to get on the boat. Strange.

 

[Neildeb2]

The boats I've used to check are in the slip next to me and in the slip 3 down and across.
Interestingly, Marine traffic.com picks up my fa50 from Camas Washington 14 days ago while furuno was testing it...

 

[Sparky Wire]

That would point to poor AIS whip or blockage then. I guess it could also be the cable from the unit to the whip. If testing in Camas reached a volunteer site there it is just extra verification the unit and GPS do indeed work. The only remaining items in question is the mounting on the boat (possible blockages) or the Whip and cable.

 

[Neildeb2]

Figured it out. Bottom liner up front: the antenna cable was damaged.
Details: The antenna is a Morad setup, a higher-end marine antenna manufacturer in Bellingham, WA. It's a quality antenna. However, at some time in the past someone damaged the antenna cable at the joint where it INTERNALLY connects to the last 2' of the antenna. The shielding braid was torn from the connector, and the center antenna wire was broken so there was no continuity between the FA-50 connecting and the actual antenna.
That explains why it would receive (the antenna cable acted as a weak antenna), and explains why the FA-50 THOUGHT it was transmitting (blue XMIT light every 90 seconds). The antenna cable was 15' long, and 5 feet of it ran up a vertical tube, so it acted like a very poorly tuned antenna.
The important lessons for me are:
1. I have NO NETWORK CABLES connecting my FA-50 to my NavNet 3D, and it works (xmit and receive). The only connections are

 

[Neildeb2]

(sorry - accidentally hit "send")
The only connections are:
- the power cable red and black wires (to 12vdc)
- the tiny white and blue wires from the power cable (to the NavNet3D MFDBB)
- The GPS antenna cable
- The MORAD AIS antenna cable
While troubleshooting a Furuno rep insisted there had to be a network cable going to a hub, then to the NN3d BB.
Not true.
2. The blue flashing "xmit" light doesn't mean it's transmitting. It just means it thinks it is. Because a Furuno rep insisted that if it's flashing blue then it's transmitting - I just wasn't using the right sources to pick up my transmissions.
3. I assumed the antenna cable and antenna couldn't be the issue. There are no moving parts, no circuits, and the cable appeared intact/undamaged, had been in the boat for years, and the antenna was a high quality one. It wasn't until I disassembled the antenna and looked inside that I found the damage to the cable. Repaired it and reassembled - it works like a champ.

 

[wkearney99]

Figured it out. Bottom liner up front: the antenna cable was damaged.
Details: The antenna is a Morad setup, a higher-end marine antenna manufacturer in Bellingham, WA. It's a quality antenna. However, at some time in the past someone damaged the antenna cable at the joint where it INTERNALLY connects to the last 2' of the antenna. The shielding braid was torn from the connector, and the center antenna wire was broken so there was no continuity between the FA-50 connecting and the actual antenna.

That explains why it would receive (the antenna cable acted as a weak antenna), and explains why the FA-50 THOUGHT it was transmitting (blue XMIT light every 90 seconds). The antenna cable was 15' long, and 5 feet of it ran up a vertical tube, so it acted like a very poorly tuned antenna.

Anything that transmits is going to "think" that is what it is doing. There's no way for any RF device to know that once it's engaged the transmitter that the signal didn't actually "go anywhere" because of a bad antenna. The FA-50 was doing the right thing, and telling you that via the blue light.

I suspected the antenna. But is indeed a hard thing to rule out because it's a fixed item on the boat and you don't usually assume that fixed things, especially ones with no moving parts, are going to suddenly "go bad".

I'd wonder if a simple continuity test would have indicated that the antenna was broken? Or putting a SWR meter on it? I've only rarely had to debug antenna situations, and usually test by using a replacement. But that's not the sort of thing most folks are going to have 'on-hand' for troubleshooting.

 

[gtstang462002]

Figured it out. Bottom liner up front: the antenna cable was damaged.
Details: The antenna is a Morad setup, a higher-end marine antenna manufacturer in Bellingham, WA. It's a quality antenna. However, at some time in the past someone damaged the antenna cable at the joint where it INTERNALLY connects to the last 2' of the antenna. The shielding braid was torn from the connector, and the center antenna wire was broken so there was no continuity between the FA-50 connecting and the actual antenna.

That explains why it would receive (the antenna cable acted as a weak antenna), and explains why the FA-50 THOUGHT it was transmitting (blue XMIT light every 90 seconds). The antenna cable was 15' long, and 5 feet of it ran up a vertical tube, so it acted like a very poorly tuned antenna.

Anything that transmits is going to "think" that is what it is doing. There's no way for any RF device to know that once it's engaged the transmitter that the signal didn't actually "go anywhere" because of a bad antenna. The FA-50 was doing the right thing, and telling you that via the blue light.

I suspected the antenna. But is indeed a hard thing to rule out because it's a fixed item on the boat and you don't usually assume that fixed things, especially ones with no moving parts, are going to suddenly "go bad".

I'd wonder if a simple continuity test would have indicated that the antenna was broken? Or putting a SWR meter on it? I've only rarely had to debug antenna situations, and usually test by using a replacement. But that's not the sort of thing most folks are going to have 'on-hand' for troubleshooting.

An SWR meter would have shown a bad antenna for sure due to the reflected RF back feeding the antenna cable. As mentioned a couple of times, you don't generally suspect objets that are stationary to suddenly go bad but they do from time to time.