AIS not visible on MarineTraffic app

[MikeCondor]

Hi-
We have B&G Zeus3 with NAIS 500 transmitter installed. Other boats can see our AIS signal, MMSI, etc, but it doesn't appear on the phone app MarineTraffic. The support for that app seems pretty tortuous. It's a nice safety check to know one can be seen by glancing at the phone app. Has anyone experienced the same?

[mglonnro]

Originally Posted by MikeCondor

Hi-
We have B&G Zeus3 with NAIS 500 transmitter installed. Other boats can see our AIS signal, MMSI, etc, but it doesn't appear on the phone app MarineTraffic. The support for that app seems pretty tortuous. It's a nice safety check to know one can be seen by glancing at the phone app. Has anyone experienced the same?

I had this when we had a small antenna connection issue. Boats nearby saw me (and I saw them), but the signal was too weak to reach very far.

If some boat near you shows up on MarineTraffic, you can open it and check which link station it is using. If it is nearby, you might have some sort of connectivity problem.

Another thing: I assume it takes a while for the boat to show up there after it has sent off its first AIS ping. Could be more hours than days, though

[Quebramar]

The distance to the land station is an important factor. I had an all-purpose VHF antenna dedicated to the AIS and reception/visibility on marinetraffic was sometimes intermittent and certainly lost when away from stations. I changed the antenna to a special one (frequency of AIS emission is specific) and now the coverage is much better

[ahun]

Try vesselfinder, it's much quicker.

[Sailshabby]

I’ve also heard if you’re too close (phone app, I assume), it can affect things.

[redhead]

I couldn't find us the first year. I found that it takes about 15 minutes to appear on the screen. Probably not your problem but I thought I'd toss it in.

[meirriba]

As I see it, to appear on a web AIS site, your transmission must be received by a land station (that sends the data to the Internet).
The transmission can reach the landstation by one of two channels:
1. Directly. This depends on the distance of your vessel from the station and quality of your antenna.
2. Indirectly, through vessels carrying special transponders that collect AIS signals in their vicinity and and sends this data through long range radio equipment to the landbase. This of course helps you only if such a vessel comes close enough to pick your signal.
After one of the above succeeds, it takes 15 - 30 minutes for the data to appear on the website.

[MJH]

Originally Posted by MikeCondor

Hi-
We have B&G Zeus3 with NAIS 500 transmitter installed. Other boats can see our AIS signal, MMSI, etc, but it doesn't appear on the phone app MarineTraffic. The support for that app seems pretty tortuous. It's a nice safety check to know one can be seen by glancing at the phone app. Has anyone experienced the same?

It has been some time ago but I experienced the same thing and contacted MarineTraffic that my boat did not show up. I thought that there might be a lack of coverage at my location and even volunteered to host a site but they said my area was adequately covered.

While I have no problem while on a cruise, my wife can follow me when I'm aboard, and I see other vessels (particularly commercial) that are near my island home, my boat does not show up at home on its mooring buoy.

It may have something to do with the level of $ervice you are paying for and/or boat movement. Some are shown with 0 kn while others are just shown as Pleasurer Craft and no speed.

~ ~ _/) ~ ~ MJH

[Handsoff]

Hi. I had the same exact problem with Marine Traffic. It took days for my new boat to be registered. Finally showed up but I spent some time with Vesper support checking.
Good luck

[TackSeason]

Same thing here, it showed up right after I spent way too much time trying to figure out what was wrong. Just leave it on for a few days. On the bright side, I learned a lot about AIS and the software that Raymarine ships their unit with, which is really nice for a debugging tool.

[David Sandowich]

Went through some of the same issues in the past. I also operate a MT land station. The previous advice is accurate. If you are out range of a station you won't appear on MT and often you will not be picked up by the station nearest to you...go figure. There is an option on MT to show nearby stations if you are interested. Also if there are many signals being sent Class A will often over ride class B signals. The bottom line is are you being seen by vessels near you which is what the technology is made for not to be seen on our phone...but I get the satisfaction of checking. Often contacting a near by vessel to verify is an option.

[StoneCrab]

Originally Posted by meirriba

As I see it, to appear on a web AIS site, your transmission must be received by a land station (that sends the data to the Internet).
The transmission can reach the landstation by one of two channels:
1. Directly. This depends on the distance of your vessel from the station and quality of your antenna.
2. Indirectly, through vessels carrying special transponders that collect AIS signals in their vicinity and and sends this data through long range radio equipment to the landbase. This of course helps you only if such a vessel comes close enough to pick your signal.
After one of the above succeeds, it takes 15 - 30 minutes for the data to appear on the website.

The above statements are accurate, which points to the antenna as a critical issue. If you don't have a strong signal going out, you will not be seen by the land stations or other repeater boats.

You don't mention whether you are a sailboat or monohull power boat. Sailboats often use a less directional antenna so that the signal can still be heading toward the horizon when the boat it heeled.

An example would be using a 1/4 wave steel rod vs a 5/8 wave or a base loaded antenna.

The 5/8th wave antenna puts out a narrower beam horizontally which will reach further to the horizon if the mast is perpendicular to the water....not heeled. When you heel over, that same, narrow signal, is being transmitted into the nearby waves and into the sky, abeam of the boat.

The 1/4 wave antenna puts out a radiation pattern that is more similar to a beachball... round, and the same in all directions, but with less intensity than the narrow beam 5/8 wave. With the beachball analogy, as the boat heels, the same power is still being broadcast to the horizon due to the unidirectional nature of the transmission. This can make the 1/4 wave, simpler antenna actually more effective than the more expensive, higher gain 5/8 wave antenna.

What frequency the antenna is resonant on also makes a big difference in how much radio frequency energy actually leaves the antenna. At the resonant frequency, the entire wave is free to leave the wire, exciting the atmosphere around the boat. If the resonant frequency is actually much lower (check out AIS vs VHF frequencies) the SWR or standing wave ratio for the AIS frequencies will be poor resulting in a lot of power losses in both the antenna and the co-ax feedline. There are test units which measure SWR. If you can borrow one that shows forward power and reflected power (the two needle type), you can see how much power you are losing by looking at the reflected power.

The length and type of co-ax used between the radio and the antenna also makes a huge difference. There are tables which show the loss per 100 feet of co-ax for the different types. At high VHF frequencies, the quality of the co-ax makes a huge difference. There is less difference at lower frequencies, like the Amateur Radio HF frequencies. If you lose 3 dB in your co-ax, your antenna only sees 1/2 the power of the radio.

If you have skinny co-ax, say around 1/4" in diameter, replace it. The thin co-ax is either RG-8X 50 ohm cable or worse, RG6 or RG58 75 ohm cable TV cable. The marine radio is looking for an impedance matching 50 ohm cable with a highly rated dielectric and double shielding (braid and foil) These requirements generally push the solution toward much larger diameter co-ax like LMR400 which is stiffer and about 1/2" in diameter.

West Marine carries a marine version of this cable which has a white exterior. All the braiding is tinned for enhanced corrosion resistance. The LMR400 is typically rated for direct burial which means that they have injected a moisture resistant jelly like material between the outer jacket and braid. The outer jacket is also UV resistant.

This brings me to my final point, which is that co-ax doesn't last forever and needs to be replaced periodically. It also suffers from moisture damage. If the center dialectric is allowed to absorb moisture or get wet, the performance will drop off.

So in summary, a short list of things that can be the cause of your AIS system not performing up to your expectations can be:
1. Wrong type of antenna - signal pointing above horizon
2. Antenna tuned to the wrong frequency (high SWR)
3. Wrong type of co-ax was used (too much attenuation, wrong impedance, high losses in the co-ax)
4. Cheap co-ax with insufficient shielding - foil and braid is best
5. Old or moisture damaged or compromised co-ax
6. Improperly installed co-ax fittings - typically PL-259

Most of these things can be diagnosed with an antenna analyzer if you can borrow one or borrow the owner for a system check, you wont regret it.

Antennas are funny things. They are more important than the transmitter in my opinion. I mounted a radio in the cockpit with a vertical whip off the stern rail. One day I was sailing along with the cockpit radio on standby and made a comment to my friend about how quiet everything was that day with very few calls. He turned on the salon radio and we were blasted with traffic. Due to the antenna, its low height and how it was run, the cockpit radio wasn't picking up the calls and I was blissfully ignorant because I didn't know about the calls that I was not hearing. I just thought it was a quiet day. You were smart to check your AIS system. You caught a problem early.