Does anyone monitor AIS (Ship and Vessel Tracking?)

[KB4ERT]

I have a dedicated RPI and a dAISy hat that I track ships and vessels at sea. I’m located about 25 miles from the Atlantic Ocean in South Carolina USA. If I were closer to the ocean, I know I would see more vessels. I currently have a 2meter/70 centimeter Diamond X50 antenna, (that is a problem), up about 14 ft. HAAT, (that is a problem), RG-58X coax, 25 ft., a 6" jumper from a SO239 to a SMA to the dAISy hat.

I see just a few vessels, and I feed them to VesselFinder and AIShub. Does anyone have any advice about better coverage? I do have an option to move the RPI about 12 miles closer to the sea. I’m looking for some “configuration” settings.

Thanks in advance!
KB4ERT

[foxhunter]

I assume it’s more difficult as they are all “on the ground”, if the tracking works the same way as for flights.

[geckoVN]

@foxhunter

if the tracking works the same way as for flights.

High band VHF is much less LOS than microwaves.

[wiedehopf]

You could always try a filtered preamp: 162MHz Filtered Preamp

I’m not aware how the performance of the HAT you are using is compared to using an rtl-sdr dongle.

[caius]

@KB4ERT

Does anyone have any advice about better coverage?

You need the antenna as high as possible and as close to the sea as possible since AIS is still mostly line of sight and I’ve yet to see a container ship passing overhead.

AIS class A (used on larger vessels) transmits with 12.5W and is usually receivable up to about 50 miles depending on how high the ships (and your) antenna is. Class B used on small craft only uses 2W transmitter power and the antennas are usually much closer to the surface, except on sailing yachts that tend to put them on top of the mast. There is also class B+ which uses 5W, but is still quite new so not as common. Reception range for them is consequently more limited.

Atmospheric ducting can help a lot with range however - I’ve solidly received ships at 150nm away but you can’t count on that all the time.

I haven’t tried any rtl-sdr monitoring on AIS as I don’t live close enough to the sea, but I’ve used it extensively while sailing. Moving the antenna from the pushpit rail (about 1.5m asl) to the top of the mast (12m) made a noticeable difference.

[mikkyo]

Apparently made by uputronics

dAISy HAT

[keithma]

Not yet but this is something I’m keen to play with. I’m relatively close to the sea and some major ports. An RTL-SDR dongle supposedly isn’t very good for AIS so the dAISy hat seems to be the way to go.

[SoNic67]

@caius

but I’ve used it extensively while sailing.

Can’t hide money

[SoNic67]

@mikkyo

Apparently made by uputronics

Nope. They just sell it.

Made by: https://shop.wegmatt.com/

Another link, with the manufacturer responding: https://www.tindie.com/products/astuder/daisy-hat-ais-receiver-for-raspberry-pi/#specs

[caius]

@SoNic67

Can’t hide money

The trick is to go on someone else’s boat.

[Dxista]

@caius

but I’ve used it extensively while sailing.

@SoNic67

Can’t hide money

@caius

The trick is to go on someone else’s boat.

That was precious. Well played by all involved.

[Dxista]

@SoNic67

Made by: https://shop.wegmatt.com/

This one looks interesting, and the price is reasonable, including the shipping charge to Canada, which is usually much higher:

dAISy AIS Receiver - The Original

I’m too far from the St. Lawrence river, but who knows. I don’t think the small vessels on both the Ottawa and Rideau rivers use AIS.

[SoNic67]

The Montreal guys are in a better position…

MarineTraffic: Global Ship Tracking Intelligence | AIS Marine Traffic

[Dxista]

@SoNic67

The Montreal guys are in a better position…

Most definitively. I would likely be a lot more familiar with AIS if I lived there.

I used to decode DSC*, it’s like “AIS” on HF.

*Edited: Thank you @caius for catching it.

[SoNic67]

AIS works on 161.975 and 162.025 MHz. How to build a 162.5Mhz antenna (close enough):

https://www.weather.gov/cae/antenna.html

[caius]

@Dxista

I used to decode DCS, it’s like “AIS” on HF.

DSC - digital selective calling. Works on marine VHF as well, but it’s much more useful on HF.

[Dxista]

@caius

DSC - digital selective calling. Works on marine VHF as well, but it’s much more useful on HF.

Yep. Like ADS-B with ACARS on VHF and HFDL on HF.

[abcd567]

@dvsvejk

There are several AIS decoders out there but I have had great success and been impressed with AIS-catcher

 

Thanks a lot @dvsvejk for providing link to AIS-catcher’s Github site.

 

GitHub - jvde-github/AIS-catcher: AIS receiver for RTL SDR dongles, Airspy...

 

Instead of installing AIS-catcher’s Linux version on RPI, I have downloaded it’s Windows version from the AIS-catcher’s Github site. The Windows version does not require installation. Just unzip the downloaded file and double-click the file start.bat to start it. My Windows Desktop had DVB-T plugged into it with it’s driver Zadig already installed.

During couple of hours of operation, could receive only two message. The reason is that I am using Black generic DVB-T with it’s stock mag-mount antenna, placed inside room.

 

!AIVDM,1,1,,A,69o5=jBKHQEqRAVSe55Bb4,0*07 ( MSG: 6, REPEAT: 0, MMSI: 661736905, signalpower: -39.2589, ppm: 1.15741, timestamp: 20220918214954) `

 

{"class":"AIS","device":"AIS-catcher","rxtime":"20220919005743","scaled":true,"channel":"B","nmea":["!AIVDM,1,1,,B,>bTsLiIo6udC,0*39"],"signalpower":-38.339664,"ppm":1.446759,"type":14,"repeat":2,"mmsi":709811397,"text":"]1/[D=EVO8TUYAQ.9/K#9D^N/C8YD(UZ.XL=[559'G"}

 

{"class":"AIS","device":"AIS-catcher","rxtime":"20220919173006","scaled":true,"channel":"B","nmea":["!AIVDM,1,1,,B,3,0*16"],"signalpower":-41.194973,"ppm":-0.868056,"type":3,"repeat":3,"mmsi":544463866,"status":2,"status_text":"Not under command","turn":0,"speed":36.700001,"accuracy":false,"lon":-66.406883,"lat":89.573463,"course":395.600006,"heading":477,"second":50,"maneuver":1,"raim":true,"radio":334493}

 

I will next weekend try with ProStick (Orange) which has a builtin LNA, and use a long vertical wire taped to window glass to act as antenna.

I have also downloaded and installed on Windows PC, a GUI program OpenCPN to display on Map, the ships detected b AIS-Catcher.

I have modified the default file start.bat to include
(1) setting gain to maximum
(2) display detailed output
(3)save the output to a text-file AIS-Catcher-output.txt

Original file start.bat:

AIS-catcher -v 10 -u 127.0.0.1 10110 -M DT
PAUSE

Modified file start.bat:

AIS-catcher -v 10 -u 127.0.0.1 10110 -M DT -o 4 -gr TUNER 50.0 RTLAGC on -p 0 >> C:\Users\abcd\Desktop\SHOTCUTS\AIS-Catcher-output.txt   
PAUSE

 

 

 

Replaced Black Generic DVB-T by FA Orange Prostick - Antenna is same (DVB-T’s stock mag-mount whip)

 

 

 

My Location (Toronto, Canada) has 3 Large Lakes around it:

[abcd567]

@dvsvejk

I have now un-screwed the 12 cm long whip from base of mag-mount antenna, and tied a 46 cm (1/4 wl at 162 Mhz) wire to the brass stud of mag-mount base, and started AIS-catcher.

Waiting to catch a ship. I feel like throwing a fishing line in the Lake Ontario, and waiting for a fish to take the bait

[geckoVN]

@abcd567

Waiting to catch a ship.

If you are not receiving any traffic, it’s not from a lack of vessels