Love for AIS

Re: EasyAIS link update

Yep, that's the page I read which made me a more relaxed re the 'dual channel' type of receiver like Nasa's.

Does anyone on here use the EasyAIS engine (or other makes) and could give us a heads-up?
 
The NASA AIS engine takes GPS data via an NMEA input and merges it with the AIS data (at a higher data rate). This saves having another serial input to the PC or data splitting software such as Fransongate and is fully compatible with SeaClear.
 
Early NASA only listened to one channel.. The ones on sale now, do both.

I achieved your 7-8 miles on the pushpit when I was using a short helical coil antenna. I changed it for a 1metre whip from JG tech and more than doubled the range. If I want more, I do a change over beteen radio and AIS so that my VHF radio has the shorter range.
 
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Early NASA only listened to one channel.. The ones on sale now, do both.


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any idea of serial numbers/dates of change over. I have had one for couple (maybe 3) years. Works fine but if there is an improvement to have I will take it since they are cheap enough. Not bothered about class B though - we have AIS for big ships.
 
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I would welcome seeing a comparison between shipplotter and seaclear if anyone has done one. I use the later a good deal and rate it highly, but shipplotter does seem to be mentioned on the forums a lot.

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Well, for a start ShipPlotter is not just an AIS plotting utility, most importantly it can decode AIS signals from any VHF FM receiver that can receive marine band and has an FM discriminator output. Thus ShipPlotter doesn't need an AIS "engine", just a receiver and a decent PC sound chip. If you don't have such a receiver (an Icom PCR-1000 communications receiver does the job very well) then it will plot from the NMEA output of an "engine". ShipPlotter will also output AIS data on a COM port in NMEA format so other units can use the output. It can also pass the data out on a network so you can have more than one PC showing the plot at the same time.

Both Seaclear and ShipPlotter have to use self scanned or screen-dumped charts which you have to calibrate. However, for collision avoidance assistance these are not necessary as a radar type display is all you need. On ShipPlotter at least, the radar dispaly can be used North-up or Head-up but I don't know about Seaclear. ShipPlotter can be programmed to to produce audio and visual alerts, the latter giving ship's MMSI or Name if received, CPA and time to CPA.

Does that help? ShipPlotter is my preference, especailly as I don't use an AIS "engine".
 
Hey Oldhand,

AIS is brand new to me, but are you saying that I could use an HF transceiver like my Icom 706 MkII for example to feed directly to Shipplotter via my laptop? This set will receive/transmit on VHF bands as well as AM so would seem to be suitable. If so, this would be a super answer to AIS for me, and save a good few pennies!

I have downloaded Seaclear but have not got Shipplotter on the laptop yet.

I assume that either will work with my Tsunami 99 charts.
 
I have no expereince of your particular Icom transceiver but what is required for using ShipPlotter as the decoder as well as a plotter is:
1. A direct FM discriminator output. If it doesn't have this then it may be able to be modified to provide one. The ShipPlotter web-site has a link to pages on how to modify some common receivers but your Icom may need professional intervention if it hasn't got this output. The normal audio output always has some filtering which will affect the the modulated AIS signal and it won't decode.
2. Obviously from the above, a FM receiving mode, which you say you have.
3. An FM reception bandwith of at least 9kHz, I use 15kHz.
4. The ability to tune the frequency in 10Hz steps helps to tune out possible receiver frequency errors, i.e. the frequency displayed may not be quite what you actually get.
5. A screened cable to connect the receiver's discriminator output directly to the line-in or microphone-in sockets on your PC.
6. P.C. should have a decent sound chip, preferably SoundBlaster compatable, and the sound system must not have high interference from other sources, internal or otherwise. If the PC's sound system is not good enough, like on my boat PC, a Trust USB external sound "card" (a small box) works just fine.

The FM discriminator output is the crucial bit and I suspect your transceiver lacks this. If so you could try asking Icom where to attach a wire in the circuitry to go to a connector you could install in the case. This output on the PCR-1000 receiver is a BNC co-ax socket.

Neither ShipPlotter nor SaeClear can use your Tsunami 99 charts directly. You will have to arrange for Tsunami to display the chart areas you want, screen-dump them, crop them in a picture editor and then save them as Windows bitmap files. When loaded into ShipPlotter they can be calibrated directly by entering the co-ordinates of 3 known points, not very difficult but needs to be done accurately. If I remember correctly, you have to use a separate utility to calibrate charts for SeaClear but then that is just a plotter and won't decode your AIS signals from the Icom.

If you can get the required output from your Icom and use ShipPlotter, you should be very pleased with the end result as you won't need any additional hardware or antenna.
 
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