FA50 Troubleshooting



Hallo to all Forum Users and Furuno Support Staff,

this is my first post in this forum and i hope to find some hints. I take care for a NAVnet3D installation on a SY Chrisco with a full Furuno installation since Dezember 2010.

It contains a Blackbox, Radome, HUB101, FA50, 2 GPS37. Everything was running very smooth during the last two years. Two month ago the radome unit was suddenly broken and 3 weeks later the networkport of the AIS50. We did a big check and exchanged the electronic of the Radome by service and installed a new HUB101 and AIS50. Of cource we checked all Cable Connections.
After that the FA50 was running again for about one week and freezes. With a restart it was working agein. We thought about powerpeaks and put another DCDC Converter in front of the HUB101 and the FA50.

After 2 Weeks it freezes again. Now i run out of ideas what to check or test.

Some Questions:

Could we connect one of the GPS Antennas from the GPS37 to the FA50?
Its because i use http://www.vesselfinder.com in the past to control the AIS Unit and found that since the new Unit is installed the Position is drifting more that some meters. It could be 100-200 Meters.

Could a broken GPS antenna or antenna Amplifier cause the unit to freeze?

Could a broken VHF antenna or the sudden short cut in the Antenna Cable cause the unit to freeze?

The FA50 is conneted with 12V by DCDC Converter directly from the MAIN Batterie with 24V.
It is connected with the delivered GPS antenna with a Amplifier in between. Cable lenght is about 35 Meters.
VHF Antenna is a RR Biscaya Unit with a Splitter in between.

greeting from Hamburg, Germany and a good start for 2012
Jens Meske

Johnny Electron

Staff member
The GPS connected to the FA50 must be working with a GPS fix for the FA50 to transmit. If the AIS boat position is moving around as much as you say, it appears that your antenna has some nearby RF (on or off the boat) that causes the GPS to vary. If the RF is strong enough and allowed to continue (like GPS being hit by your radar constantly) it will cause the antenna to go bad. If that happens, the AIS will stop transmitting or be intermittent as the antenna gets damaged from the strong RF. Yes, you can use the coax antenna from a GP32 or GP37 on the FA50 AIS for testing purposes.


Thank you Jonny for your reply,

i will ask the skipper to check if radar is turned off.
Its good to know that we can use the other GPS Antennas also.

Wish you a nice party today
Greetings from Germany, Hamburg