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Old 06-06-2012, 00:10   #1
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How do I know my AIS is working ?

I just received my Digital Yacht uAIS receiver, an all in one AIS receiver with an antenna that connect via a usb. I installed it, and my Vista laptop set it as com 13. I have opencpn set for com13 38,400 baud. Since it can't pickup any vessels I have no idea if it is working.

I also set it up on Seaclear II because you can monitor the data stream and nothing is coming from the AIS, only the GPS is sending data. I don't know enough about how AIS works, should I be seeing some data in the data stream even if no transmitters are in range?

Can wait to try this out on the water.
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Old 06-06-2012, 00:25   #2
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Re: How do I know my AIS is working?

I'm not positive 100% on this, but I don't think the AIS will send a sentence until it receives something. Are you hundreds of miles from a port?

if the gps is sending data I think you have your connections and baud rate right.
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Old 06-06-2012, 00:50   #3
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Re: How do I know my AIS is working?

Some small help on offer. You first need to click on the AIS Icon, (centre top), but you have probably done this. If it then has a question mark over it you are not receiving. If the icon only shows a yellow and a green ship, your settings are ok and receiving, (if there are ships in range), best way to check that is use Marinetraffic.com at the same time. I have been trialing this today in my car and moving to various elevations and antenna height was critical. Regards MB
PS I am now at home 6 miles from the sea with a high antenna, an hour ago I had 9 targets, now none but I know there are still there. Landbased receiving must be subject to many variables.
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Old 06-06-2012, 00:56   #4
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Re: How do I know my AIS is working?

I am probably 15 miles from any ais transmitting vessel. I believe that the question mark in the icon mean that Opencpn has been set to filter out something like boats at anchor. I can make the question mark go away by unclicking that setting.

Maybe it doesn't send any sentences unless it receives something. I know the gps works, but it's a separate device. I guess I will have to take a drive to a harbor soon. Thanks for the help.
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Old 06-06-2012, 08:30   #5
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Re: How do I know my AIS is working?

Quote:
Originally Posted by StargazerWA View Post
I just received my Digital Yacht uAIS receiver, an all in one AIS receiver with an antenna that connect via a usb. I installed it, and my Vista laptop set it as com 13. I have opencpn set for com13 38,400 baud. Since it can't pickup any vessels I have no idea if it is working.

I also set it up on Seaclear II because you can monitor the data stream and nothing is coming from the AIS, only the GPS is sending data. I don't know enough about how AIS works, should I be seeing some data in the data stream even if no transmitters are in range?

Can wait to try this out on the water.
AIS is based on VHF radio, bascially line of sight. That means your reception is based on location of both the transmit and receiving antennas.

In other words higher is better. I have two VHF antennas on my boat and experimented with switching the AIS from the stern antenna, which is 15 feet off the water to the mast head antenna, which is about 65 feet of the water.

Reception in the San Francisco Bay area was improved by about 25 miles using the mast head VHF antenna.

I did a quick internet search on your unit and on one of the sales pages was the below quote:

* NOTE similar to hand-held VHFs, which have a reduced range compared to fixed mount VHFs (no antenna ground plane), the uAIS does not have the same range as the AIS100/200 black box AIS units. If maximum AIS range is your highest priority then one of the other Digital Yacht receivers should be used, but for small boats with the aerial mounted at deck level, 10 miles is a good range for AIS and the uAIS is recommended

With that in mind you should go down to the marina and see what happens.

You can judge how far your distance is by comparing targets to an internet based AIS receiver (See link below). That should get you an idea of the range of your unit, which again will be impacted by antenna heights and weather conditions.

Fair winds

Live Ships Map - AIS - Vessel Traffic and Positions

or

http://ais3.siitech.net/VTSLite/AView.aspx
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Old 06-06-2012, 09:53   #6
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Re: How do I know my AIS is working?

I got my AIS antenna over the bimini top, perhaps 10 feet of the water and have picked up targets 29 miles away. (The transmitting antenna was probably 100 feet up)

If you are close to a port you should pick up targets within minutes...
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Old 06-06-2012, 10:11   #7
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Re: How do I know my AIS is working?

The AIS receivers don't put out any sentences unless there is an AIS signal in range. You should be able to use hyperterminal to look at the output, unless Microsoft took that off Vista.
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Old 06-06-2012, 10:17   #8
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Re: How do I know my AIS is working?

Thanks, I didnt really expect to pickup a signal at home, it's just that without a signal there doesn't seem to be anyway to see if my unit is working and that it is connected to opencpn properly. I did some more research after my post and this seems to be the case for all ais units. Thanks, I will let everyone know how it works.
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Old 06-06-2012, 13:25   #9
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Re: How do I know my AIS is working?

In the Mediterranian you might see AIS signals 200 miles and more away due to tropospheric ducting especially in the evening.

Gerhard

Using an AIS capable VHF (RO4800 from Radio Ocean/Furuno) attached to OpenCPN.
VHF antenna in mast top.
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Old 26-06-2012, 16:41   #10
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Re: How do I know my AIS is working?

Just to confirm (from the Horse's mouth so to speak), all Digital Yacht Receivers only send out AIS data (VDM message) when they receive an AIS position report from another vessel. If you are outside of AIS reception range when you are testing an AIS receiver you will not see any AIS data coming on on the USB COM port.

If you have an AIS100USB, AIS100Pro or iAIS, then you can check that data is being transmitted on the USB port by turning the unit off and then on, which causes it to send out a Boot-Up text message which can be displayed on an NMEA monitoring program - like our free NMEA Display program (click here to download)

Do bear in mind that typically you should expect to receive Class A targets at a minimum of 10-15 miles even with an aerial at deck level. Class B targets (due to their 2W transmit power) are unlikely to be detected over 7-8 miles even in perfect conditions.

Hope this answer is useful.
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Old 01-07-2012, 02:30   #11
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Re: How do I know my AIS is working?

Thanks for the the link to the nema checker !
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