Curious AIS Problem

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oldgit

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Digital Yacht. 1500. Transponder and Splitter.
AIS both Tx and Rx was working OK
Will now only Tx my location.
AIS logo not lighting up and No other vessels displayed on Plotter.

Recently called up a marina on VHF to gain entry and was told signal very weak and virtually unreadable. Could hardly hear their response.
Handheld resolved the situation.
The VHF radio can be made to function perfectly both on Tx and Rx by plugging directly a different aerial.
Suspecting the splitter and have downloaded the intruction and installation panel
But first before I start pulling apart the instrument panel apart in the morning , suggestions !
Fortunately got good idea where all the bits are buried.
 
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Don’t underestimate how the slightest bit of corrosion or a poor connection can affect signal. I would bypass the splitter first and see if that makes any difference. If not then it is the aerial or a connection. You can plug the AIS unit into a laptop via usb and with the Digital Yacht software you can see the signal qualit whilst you tinker.
 
Keith-i said:
Don’t underestimate how the slightest bit of corrosion or a poor connection can affect signal. I would bypass the splitter first and see if that makes any difference. If not then it is the aerial or a connection. You can plug the AIS unit into a laptop via usb and with the Digital Yacht software you can see the signal qualit whilst you tinker.
Click to expand...

Found the DY software disc in the boat manual folder, will take the laptop and try not to matters any worse.
 
Sounds like an antenna issue or no power to the splitter.
Check you have everything switched on? As an example I need to have the speed /depth log on in order to power up the network .
 
MartynG said:
Sounds like an antenna issue or no power to the splitter.
Check you have everything switched on? As an example I need to have the speed /depth log on in order to power up the network .
Click to expand...

90% certain its the splitter either faulty or lost its 12V.
Used the software to interrogate the AIS unit and its telling me the transponder is sending and receiving but its only receiving AIS signals from two other neaerbye boats both on our moorings around 100m away.

Plugged a new aerial into the system just downstream of the existing antenna and no difference to signal strength on VHF or ability of AIS to receive distant signals.
Spend the day dismantling most of the boat in a dismal failed attempt to find out where the splitter in hidden. Gave up in the end.
Plan B is to get a PL259 to BNC adapter, bypass the splitter/cable /existing antenna and directly feed the AIS via a new aerial to confirm its splitter.
If it confirms its the splitter, merely a case of finding it !
 
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When I installed AIS I found it cheaper to fit a separate antenna for the AIS compared to a splitter .

Its anyone's guess where the splitter is located but it made sense for me to locate the plotter, vhf and AIS near each other so as to minimise length of expensive network cables. If I did have a splitter it would be in the same vicinity .
 
MartynG said:
When I installed AIS I found it cheaper to fit a separate antenna for the AIS compared to a splitter .

Its anyone's guess where the splitter is located but it made sense for me to locate the plotter, vhf and AIS near each other so as to minimise length of expensive network cables. If I did have a splitter it would be in the same vicinity .
Click to expand...

My first thought was to simply fit another dedicated AIS aerial.
However getting any cable from the new antenna to the AIS transponder in the saloon is absolute nightmare and still leaves the problem of providing any vhf signal to the marine radio from original aerial.
The transducer is assuring me its working perfectly

The plotter is telling different story.

Grrrr................
 
VSWR. All points to the splitter, however Digital Yacht are suggesting their splitters rarely cause problems..
Spent bit more time today trying the find the splitter , now rather think they have hidden it somewhere up on the fly closer to the antennas.
 
DrSpock said:
If it's not the splitter (which makes the most sense) then it could be a faulty AIS hogging the communication.
Click to expand...

"Digital Yacht" have been very helpful indeed and are reasonably confident that their AIS transponder is function correctly.
You can watch it go through its start up sequence by way of some LED s on the front of the unit until it eventually only displays a solid green light and the boat can be visibly seen to be sending a signal on any internet ship tracking apps.
It will only receive signals from boats a very short distance away.
DY . have suggested to check the settings in the Raymarine "E" series, they might need changing for it to function with non Raymarine AIS tranducer.
If all else fails, simply going to fit a dedicated third antenna for the AIS and run a new bit of RG58 directly from existing ant to VHF and totally by pass the artfully hidden splitter.

Only those who have ever tried to run any wiring or co-ax cable from fly to saloon in modern "ish" boat will be looking forward to digging out shards of glassfibre out of your knuckles and realising that the p*** cable has come undone from the drawcord after being given a good tug after jamming inside the ducting.
 
DrSpock said:
Daft question - you haven't put it into silent / dark mode have you which disables transmission?
Click to expand...
Have checked that.

You can interrogate the AIS transducer using a laptop and can turn silent mode off and on with software , def switched ON.
The chartplotter indicates the AIS is in silent mode even though it's transmitting a signal.?
 
DrSpock said:
You need to flip the silent mode through the chartplotter menu and see what changes as it sounds like it's out of sync.
Click to expand...

Have delved into the chartplotter AIS options menu,suspect eventually the "Know when you are beaten chum " sign will flash up on the MFD.
The phone call to somebody who actually knows what they are doing will follow.
 
Enabling and disabling AIS silent mode in the chart application

From the chart application:
1. Select Menu.
2. Select AIS Options.
3. Select AIS Unit Set-up.
4. Select AIS Silent Mode.
Selecting AIS Silent Mode will switch between silent mode On and Off
 
Have bypassed the elusive splitter and we now have two seperate antennas for saloon VHF and AIS.
VHF now working as it should receiving Medway VTS transmissions from around 10 miles away. The office is actually in Liverpool.
Going down to reassemble the boat and will have go at the Chartplotter settings this morning.
Fortunately ACM who built the boat, left loads of bits of cord in the voids to assist in pulling cables through.
 
oldgit said:
Have bypassed the elusive splitter and we now have two seperate antennas for saloon VHF and AIS.
VHF now working as it should receiving Medway VTS transmissions from around 10 miles away. The office is actually in Liverpool.
Going down to reassemble the boat and will have go at the Chartplotter settings this morning.
Fortunately ACM who built the boat, left loads of bits of cord in the voids to assist in pulling cables through.
Click to expand...
what about the AIS bit on the other aerial?
 
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