Inexpensive AIS listener mystery

Nasa AIS engineI’d never heard of this Nasa AIS “Engine” before, but oddly got two e-mails yesterday that referenced it. It seems almost too good to be true: a simple AIS listener that can feed ship information to a PC’s serial port for a mere $200 (plus cost of VHF antenna). It’s sold by a U.K. firm here, but does not seem to be listed at its manufacturer’s site here. One spec I see that might be a deal breaker is that a user must “Select 161.975 or 162.025 MHZ operation”. I thought AIS devices automatically use both. Please, someone, educate me on these mysteries!

Be sure to read the comment from reader Kees who owns one of these listeners, reports good performance, and terms it an �outstanding no unbelievable value…� Thanks, Kees!

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

29 Responses

  1. Eli says:

    Wow Ben…I thought I had found the cheapest AIS, but this thing takes the cake. All the specs I see say that it is dual channel, which has me assuming that it automatically pics a mode of operation; I’m obviously not sure about that though. It’s definitely worth contacting Nasa marine about it though.

  2. Kees says:

    Hi Ben,
    I bought one from another UK outfit, at the even cheaper price of GBP 109 inclusive of VAT (sales tax to you US folks). See
    It arrived on my doorstep here in The Netherlands 3 days later…
    I’ve since installed it and it works flawlessly, within it’s limits which are that it indeed only is a single channel receiver. You can choose which one it uses, as well as the sensitivity of the receiver. Since all AIS senders send messages alternately on both channels, it basically means you get half the updates. I think this is a very acceptable trade-off for the price.
    Reception distance: with my main VHF antenna at 19m height I was able to pick up anything within 30 nm (as far as I know). I have now installed a secondary VHF at about 3m above sea level, and this gives me good reception for about 10-15nm, which is all I need.
    The only gripe I have is that there is no visual feedback that the system is operative at all; no power LED or whatever. Until you have AIS senders in the neighbourhood you don’t have any way of telling whether the system works.
    All in all, this is by far the most inexpensive piece of marine electronics I have with outstanding no unbelievable value…

  3. Roger says:

    I note that there is a full featured version (screen display, etc.) of this same device for about twice as much (I think that would be about $400 US?) at

  4. Michael says:

    Did anybody know something about compability with Maxsea V11??
    thx Michael
    I�m located in NL. Maybe we can test it?

  5. Murray says:

    Im a MaxSea dealer, as long as you have the AIS / ARPA option for MaxSea 11 this will work fine,

  6. Michael says:

    Hi again!
    Yes i have the ais modul.
    I install the ais as AIS NMEA183 located on com2.
    When i control the datatransfer ther will be characters. Not as much as on com1 (GPS) but data.
    But nothing on chart??!!
    Any mistakes in the settings?
    thx Michael

  7. Murray says:

    check the baud rate of the com port as this can somtimes cause problems (i think most AIS units use 38000 not the deafult 4800

  8. Michael says:

    thats it!!
    thx a lot!!
    other question:
    now i receive a lot of data. Vessels Name, course, status, dimensions etc. ….but…no mmsi.
    Is there a way to tell maxsea which data should be shown?
    thxa Michael

  9. Murray says:

    MaxSea should pickup the MMSI number atuomatically, that said i know some people were saying MMSI numbers took time to come through on the AIS if the trafic is busy, eg they can see the targets but no infomation appears about them,
    Try moving your VHF aerial to a higher position as this will aid reception

  10. Anonymous says:

    The MMSI is included in every AIS transmission. The ship name is only in Message 5, 19 and 24B. These are more infrequent so if the software doesn’t store the MMSI to name relationships it can take a while for the name to show up.

  11. reneon says:

    belissimo guches 😉 best of the web!

  12. Derek Hodge says:

    Down here in the E. Caribbean these things are available from Budget Marine.
    They switch between the 2 channels automatically every 30 seconds.
    The CD included gives scripts to turn this feature on or off and select channel. They can be sent to the box via Hyperterminal or similar comms program.(Set baud rate to 38,400)
    I’ve been using one with the included Seaclear II charting program and it works great.
    Lots of megayacht show on the screen, the other day I counted 31 transmitting in the St.Maarten lagoon, plus a couple of cruise ships going by.

  13. Michael says:

    Hi there!
    Another question:
    On the nasa – display – unit you can set a alarm range. If a vessel comes in the unit gives a voice. Is there any way to do it in Maxsea? I figure out how to set a range, but no voice or signal is given.
    thx Michael

  14. regim says:

    again i am 🙂 adipex

  15. Eric says:

    Si-Tex makes a nice black box AIS reciever, ive seen these in action on a raymarine E-Series, pretty sweet.

  16. Anonymous says:

    Looks like Sitex just rebranded the Nasa Marine stuff.

  17. Ben Ellison Ben Ellison says:

    Note that this is a very old thread; to get the latests search Panbo for Si-Tex AIS or NASA AIS, or just look in the AIS category.

  18. Henk says:

    Hi, I use MaxSea v10 with a Nasa AIS engine connected, port settings at the right speed. I can see the data comming in and MaxSea interprets it correctly, but not targets show on the chart. Can anybody help me with this? Thanks, Henk.

  19. Paul says:

    Hello Henk, I have the same problem with a SR161. Did you solve the problem yet? Thanks,

  20. gary says:

    Paul, what software are you using? If it is Rose Point Coastal Explorer, there is a bug in the automatic setup. You have to set it up manually. Go to “Tools”, “Options”, “Port Settings” and set up the Com port interface as NMEA 0183, and the baud rate at 38,400. Then it should work.
    If not, call or email Doug Miller at MillTech Marine. He is really helpful. He even came to my house to do this for me!
    Good luck,

  21. Paul says:

    Hello Gary,
    It was Maxsea V 10, settings 38.400 Bds and mode AIS NMEA 0183. I can see the datastream on check data as O.K., (!AIVDM,…) but nothing on the screen???

  22. robbert says:

    I saw some remarks of Gary and Paul regarding the AIS\Nasa compatability with Maxsea.
    I to find problems with Maxsea version 12.1 They seem the same as Paul.
    I to see the same AIVDM info data stream and on the tab display I can see the datatranslation, but nothing on the Chart screen (vector/raster).
    I understand that I have to choose for the mobile option AIS mobile to make the data visible on the screen but this choise do’nt appear on my screen under mobiles.
    Maybe there is a slide omission that I have overlooked.
    On the Seaclear software the Nasa AIS unit works fine.
    How knows the answer.
    from Holland.

  23. henry says:

    I make any program for decode the frame AIS, !AIVDM….. but only have the code MMSI, how can get the name of ship.. Thanks…

  24. Lawrence says:

    I can’t seem to get the Nasa AIS receiver to work with the Navimaq for OS X. How do I pick the port to which my AIS receiver is connected? So far emails to barcosoft have gone unanswered and no telephone number is listed on their site.

  25. Ben Ellison Ben Ellison says:

    Try: Barco Software,
    115 5th Ave S # 400,
    La Crosse, WI
    (608) 785-7447

  26. Jeffrey O says:

    I finally got the NASA engine to talk to my C80. (I had had the pin 2 and pin 5 wires reversed).
    What I have discovered in only playing with is for an hour or so – very limited) is that:
    The C80 has an icon in the databar (v3.18). When the unit is receiving AIS data it will change from red NO AIR to a greed AIS and then display the targets on screen.
    To read the AIS data you need to place the cursor on the target and a little data window pops up. It is hardly readable. With the curson on a target you also enable AIS menu options for THAT target ONLY which appear as soft keys. You can then turn the vectors on and bring up a (readable) info window for the target. For whatever reason… I have not determined this yet) you may not get all the data fields filled in. I also got corrupted data on one target at least… length 12′ beam 32′. Have they not been programmed by the sending class A AIS? Is their signal messed up? Is the Nasa not decoding all the data?
    The C80 apparently drops off targets which do not change after a few minutes… like moored vessels. I heard this from another user… and I also noticed a moored vessel disappear… off Sag Harbor. Later I saw a vessel..(could have been the same one as I didn’t note the data)… underway heading away from Sag Harbor.
    I was not able to being up a list of all the targets… like their MARPA list. If it is there, I did not find it, but then again I find the C80 menus counter intuitive and often data can only be accessed by drilling down a specific path of menu choices. If I could only remmeber those paths!
    My antenna was an old 34″ ss Metz VHF mounted on a pole off the stern rail… 12-15′ height off the water and I received signal from vessels up to perhaps 10 miles and over land! (across Shelter Island and the North Fork!)
    This is defintely a great add on for less than $200. I sense that Raymarine will upgrade their software as the comments are received and more people add these units (B class receivers) which cost less than a long weekend of docking fees at Newport!
    The plug in power chord is very un marine like, but in my installation the unit sits on a horizontal surface and the cable is secured with wire ties so it is unlikely to pop out. Idiot lights would be helpful.
    I like it, but need to get familiar with this new technology and this particular unit.
    sv Shiva
    Contest 36s

  27. Ben Ellison Ben Ellison says:

    Jef, You should be able to find the full target list from the main soft key menu (in chart mode): AIS Options/Target Tracking/AIS list. Also, under Menu/AIS Layer Setup, you get a choice of wether to show All targets or just Dangerous ones. Raymarine’s March ’06 Reference Manual has a thorough chapter on AIS.
    By the way, the amount of data a ship shows can vary quite a bit, and the accuracy of the operator-entered items like Navigation Status and Destination is often poor.

  28. Henning says:

    Hello Henk, I have the same problem with Maxsea v10 and a Nasa engine connected. Maxsea interprets the signal correctly, but nothing appears on the screen. Can anybody help me?
    Thanks, Henning

  29. Manuel says:

    I have the same issue with Maxsea v.11?
    I can see the !AI strings coming in and can see the mmsi, ships names, lat and long etc but no ais showing up on the screen (inside the maxsea data in out settings)
    The AIS works fine with other chart plotting software and the bundled seaclear program
    Has anyone found a fix for this yet? Do I need to purchase an AIS option for Maxsea?

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