NAIS 500 not transponding

[henryk]

Hello cruisers! I have been having this problem for almost a year now . My AIS suddenly stopped transponding last year for no particular reason . I can see all the traffic around me for miles, but nobody can see me , unles you are no more than a 100 feet from me. . The antenna was new 2 years ago, and so was the splitter. I by passed the splitter, no change. I took it to the local marine electronic store and they think the gizmo it’s fine, but it’s still not transponding. Check the connection at the base of the must and everything looks fine, not a slightest sign of corrosion. Any suggestions?o

[smac999]

plug your computer into it and see what its' doing.

there is only 2 reasons an ais will receive but not transmit. one is no gps pos, and the 2nd is high ant swr, you will see the data from both on the ais software

if people can see you 100' away it's not the gps. and most likly the antenna.

[SailingHarmonie]

Originally Posted by smac999

if people can see you 100' away it's not the gps. and most likly the antenna.

Antenna, and or antenna cable, probably more likely the cable. Was the cable replaced with the antenna? Does the antenna install have a connection at the top of the mast? If yes, I'd bet a beer that that's the source of your problem. The can be tough to waterproof properly, and coax cable just HATES water...

[Tin Tin]

Do you have access to an emergency VHF antenna to test, they are about $70 and probably should carry one anyway.

[OtiumNY]

I am having precisely this same problem. NAIS500 stopped transmitting. The software says everything is fine, but nobody can see me. It is not on silent mode. The Tx light blinks green once for a millisecond every three minutes when sitting at the dock. My VHF radio works great and has no transmission issues. I tried bypassing the splitter and it still doesn't transmit my location over the AIS. Any ideas? Only my slip neighbor can see me - but boats more than 20 feet away can't. I receive AIS information just fine from 20+ miles away.

[barnakiel]

A clean and tested length of VHF wire + a tested (or new / spare) vhf antena on the rail. No splitter. Test SWR.



The device powered from the boat source (NOT by the USB link).


Now.




Plug the unit into your PC - but DO NOT, repeat : DO NOT power the AIS from your PC (yes, on some devices the device can be powered from the USB socket that sends data to the PC).


NOT in silent mode ?
SWR good ?
Device blinks on AIS send ?


Problem : Unit signal amplifier (tx circuit) broken. Service repair required.


Your message is a no-ack message. When the unit says it sent, it just says it created the packet and forwarded it to the antenna amplifier.


If the unit is x years old, then buying a new one may be cheaper than trying to fix this one. At places services demand $$$ for fixing a $$ device.


Still if the unit Rx, then it is kind of not useless, is it. So you can keep it as a receiving only device.


b.