Trouble shooting GME AIS issue

[GILow]

Hi all,

Helping a friend with an AIS issue.

Equipment: GME AIST120 Class B transceiver with GME AISS 120 splitter. Mast head conventional VHF antenna.

Symptoms: I noticed that every time he went sailing his signal would be lost by the shore stations within 5 or so miles of shore.

Testing: Yesterday we sent him out sailing while I watched him on Marine Traffic. (I am in a marina so my AIS reception is marginal). When he was about five miles out, his signal became intermittent, and sure enough, dropped out with a bit of a splutter by six miles.

Observations: He noticed a red light on the AIS unit at the time. He swapped the VHF antenna to a backup rail mounted antenna at this time and came back up on Marine Traffic after a few minutes. (There is a Marine Traffic land receiver just nearby to me, so same distance from his boat at the time.)

At this point, neither I nor the Coast Guard could reach him on the VHF radio.

At the start of the journey his VHF radio was working VERY well, getting clear across the Gulf to Coast Guard Ardrossan (30+ miles away) without using a repeater.

Ideas: Splitter warming up and overheating? Some kind of time based failure?

Over to the gurus for troubleshooting tips. I've never used GME AIS equipment or splitters, so I am at a bit of a loss.

[GILow]

On a side note, I see there is some kind of software to talk to the AIS transceiver, that might help, though I think the problem must be with the splitter, given the VHF radio died at the same time.

[Wotname]

I might have missed something in the OP but why aren't you simply taking the splitter out of the circuit.

If it works OK, put the splitter back in and see if it fails again; if so, splitter is confirmed unserviceable?

Do it with the AIS and then do it with the VHF.

Now this sounds too easy so maybe I have missed something in the OP.

[GILow]

Originally Posted by Wotname

I might have missed something in the OP but why aren't you simply taking the splitter out of the circuit.

If it works OK, put the splitter back in and see if it fails again; if so, splitter is confirmed unserviceable?

Do it with the AIS and then do it with the VHF.

Now this sounds too easy so maybe I have missed something in the OP.

No, you haven't missed anything. That sounds like a good strategy.

Yesterday's test was somewhat hindered by the fact that I was trying to get an assignment finished by midnight, so I was doing it all by remote while very distracted. Originally I was going to go out sailing with the boat owner.

He sailed out of mobile phone range so we were dependent on the VHF, and once that died, it was, frankly, untidy, until he sailed back into phone range again.

I just thought I'd get this up here because there may be CF members who have used this equipment and seen something similar. (If they have, they didn't post about it here, or at least I cannot find their posts.)

My first plan, however, is to see if the issue is time based, simply by getting down to his boat and leaving the AIS on for a couple of hours. The apparent range limitation may well be a red herring, it might simply be that he covers about the same distance in the same time when he goes sailing.

Once I can recreate the fault, then yes, I will eliminate the splitter from the equation. Though, in a way, that was done when he hooked the AIS up to the rail mounted antenna yesterday. (I suggested he buy one since it would serve a fallback if his mast goes overboard and it would make testing much easier. Unfortunately, I was not on board to do all the tests I had planned.)

Anyway, yes, your strategy will be applied, though I am hoping for some CF member to chime in with their experience of this unit.

Matt

[Wotname]

Originally Posted by GILow

No, you haven't missed anything. That sounds like a good strategy.

.............

I just thought I'd get this up here because there may be CF members who have used this equipment and seen something similar. (If they have, they didn't post about it here, or at least I cannot find their posts.)

...............

Good point and it is the one I overlooked!

Check equipment for previous known common defects

Good luck with resolving your mate's issue. I know you will update the thread accordingly!

[GILow]

Well the first update is... a bit embarrassing for all invloved.

So, it turns out the red light was on from the very beginning. This I have filed under "interesting" as well as "would have been good to know yesterday".

And the VHF stopped working because he got muddled, thinking he had connected the AIS to the stern rail antenna, but turns out he had disconnected the VHF. (Not sure whether he connected it to the stern rail antenna INSTEAD of the AIS.)

Yeah... that has me scratching my head too... because as I noted earlier, the AIS came back on. I THOUGHT that was because he'd connected it to the stern rail antenna, but it seems not.

Anyway, at least the red light comes on immediately, so the software is likely to tell us something without a long wait.

More to follow, but still keen to hear from any GME owners who've experienced trouble-shooting their AIS.

[GILow]

Originally Posted by Wotname

...
Check equipment for previous known common defects

30 years of IT experience can be summarised thus:

1. Have you restarted it?
2. Have you checked to see if there's an update?

Not a lot to show for 30 years learning, but yeah, I always check to see if someone has already invented this particular wheel.

[Wotname]

Originally Posted by GILow

30 years of IT experience can be summarised thus:

1. Have you restarted it?
2. Have you checked to see if there's an update?

Not a lot to show for 30 years learning, but yeah, I always check to see if someone has already invented this particular wheel.

30 years of dealing with pilot defect reports can be summarised thus:

1. Let's sit together in the cockpit and you show me what is not working.
2. I won't tell you how to fly if you don't tell how to fix the avionics.

[Scrimma]

I have the same distance issue. I can pick up targets a LONG way away as it's a VHF signal, but the power the GME puts out is only about 3W, so judging by the calculations through the manual info, the GME AIS doesn't have a great range at all. The newer AIS models apparently are min 5W. I've been sailing with mine as it is now for a couple of years without any real issues, other than my fellow cruisers wondering what my speed is when I'm on the horizon. All they need to know is it's faster than them! haha.
If there is an actual solution to boost the power, then I'm all ears, but alas, I'm lead to believe there is not...

[GILow]

Originally Posted by Scrimma

I have the same distance issue. I can pick up targets a LONG way away as it's a VHF signal, but the power the GME puts out is only about 3W, so judging by the calculations through the manual info, the GME AIS doesn't have a great range at all. The newer AIS models apparently are min 5W. I've been sailing with mine as it is now for a couple of years without any real issues, other than my fellow cruisers wondering what my speed is when I'm on the horizon. All they need to know is it's faster than them! haha.
If there is an actual solution to boost the power, then I'm all ears, but alas, I'm lead to believe there is not...

Thanks Scrimma, useful data there.

Just to be clear, you are using the AIST120? And the AISS120?

Oddly enough, I checked the specs on each and while the AISS120 states a maximum input power of 12.5 watts on AIS and 25 watts on VHF (suggesting the splitter can actually handle a Class A AIS), I cannot find the output power of the AIST120. Well, I can, but oddly it is stated as 33dBm ± 1.5 dB. I don't know what that means in watts.

Wotname might be able to translate that one for me.

On the upside, the AISS120 claims less than 1 dB signal loss on transmit and zero loss on receive.

Also, Scrimma, have you ever seen the red light on your transceiver, other than during startup?

Matt

[GILow]

Originally Posted by Scrimma

I have the same distance issue. I can pick up targets a LONG way away as it's a VHF signal, but the power the GME puts out is only about 3W,...(

Actually, 3 W is a little high. I think the original Class B standard was 2 watts, but now there's an enhanced standard with 5 watt capacity. (I may be wrong.)

FWIW, my aft-arch mounted dedicated stubby AIS antenna, about 10 feet off the water, is usually detected at up to 15 miles from the land based receiver next to my marina, and it is connected to an old-style 2 watt transceiver. That's a little better than the standard expects, but in the ballpark.

[Jim Cate]

Matt, dunno about the GME gear, but the splitter on my Vesper gear has a red light that comes on when there is an excessive SWR. Any chance of looking in the manual and finding what that red thing means?

Jim

[clownfishsydney]

I had the same AIS setup on my old yacht. The aerial was mounted on the top of the mast. I was regularly seen at 20 nm by other yachts and could pick up most yachts at the same distance. I could pick up ships at up to 70 nm regularly.

So the equipment is good. It must be the actual setup or a poor aerial or connection.

[Draughty]

Hi all,
I had the red light issue recently; proAIS2 software said the antenna had a high VSWR. I changed to another antenna and no more red light.
Coast guard said they were receiving me 5x5 on the bad antenna, and I'm sure I was still sending and receiving AIS. Don't have any details on distance though.

Rgds

[Draughty]

I should have said I have the same hardware as the OP.