AIS recommendations?

n4jri

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#1
I live in an area not covered by online AIS, and am wondering what the best options might be for receiving local signals myself. Was looking at some iPad apps, but couldn't be sure about what I was seeing. Would love to be able to plot the stuff on a map, but would be happy just to receive the datal

Would like to know what works well for those of you who use it. Am thinking I could use the IF-out option in the BC436 or the PSR800 for the radio end.

73/Allen (N4JRI)

ps - also a related question. Does anyone feel like there's a reduction of traffic on Ch-13 as a result of AIS?
 

kma371

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#2
I live in an area not covered by online AIS, and am wondering what the best options might be for receiving local signals myself. Was looking at some iPad apps, but couldn't be sure about what I was seeing. Would love to be able to plot the stuff on a map, but would be happy just to receive the datal

Would like to know what works well for those of you who use it. Am thinking I could use the IF-out option in the BC436 or the PSR800 for the radio end.

73/Allen (N4JRI)

ps - also a related question. Does anyone feel like there's a reduction of traffic on Ch-13 as a result of AIS?
you could try a cheap ($15) SDR radio. i tried it and it worked here, but i'm too far inland to receive much traffic.
 

n4jri

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#5
Suggestions all appreciated, but are very high-dollar. I live in Richmond, VA which is very limited as a port and am too far from the river to be an effective AIS contributor--not likely to attract the grant of a free receiver from MarineTraffic...whose iPad app I'm currently using. Have been unable to make the RTL dongle work, but still like it (or the AIS dongle) as a possible solution if I can overcome the computer issues.

Am more interested in interfacing the signal from the IF of a scanner (I have several with the appropriate capability) with an iPad or even my PC if necessary. It would be a mobile solution as I try to get a feel for what goes on. (There is an AIS site in Hopewell, VA about 20 miles away, and vessels disappear just a few miles upstream as the river begins to bend and twist.

73/Allen (N4JRI)
 
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#6
The first to-do, before you try to decode: are you positive you can even receive the signal? Can you hear it, or, can you see it using your RTL dongle?
 
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#7
Why not apply for some FREE equipment, if your area is not covered.
https://www.marinetraffic.com/en/p/expand-coverage

I live in an area not covered by online AIS, and am wondering what the best options might be for receiving local signals myself. Was looking at some iPad apps, but couldn't be sure about what I was seeing. Would love to be able to plot the stuff on a map, but would be happy just to receive the datal

Would like to know what works well for those of you who use it. Am thinking I could use the IF-out option in the BC436 or the PSR800 for the radio end.

73/Allen (N4JRI)

ps - also a related question. Does anyone feel like there's a reduction of traffic on Ch-13 as a result of AIS?
 

n4jri

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#8
Why not apply for some FREE equipment, if your area is not covered.

https://www.marinetraffic.com/en/p/expand-coverage


Actually I don't have a good home receiving setup, but have spoken to a local ham repeater owner about applying for a free receiver and plugging it into an unused site where we wouldn't need a big investment in transmission line, etc. Was thinking that it might make good publicity for hams--helping make the info more available to small boaters who could use their mobile devices w/Internet instead of buying a high dollar plotter.

But the interest I'm expressing in this thread is for something that would work for my own casual mobile/portable use. There are lots of holes on the James River--particularly near Richmond.

The nearest online receiver at this point is actually on a buoy, maintained by local college students who are also taking tidal and other measurements and sharing with NOAA.

73/Allen (N4JRI)


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#9
Keep in mind it's not about covering a WIDE AREA, the local coverage is more important, which is where the site you mentioned has vessels drop off just up the river.

BTW if you click on the link for that site, you will see it indicate "Low Coverage"
but they do cover about 95 sq/mi

As to navigation via the internet, a boater should invest
that would be like relying on a cellphone instead of a marine radio [IMHO ]:roll:

Actually I don't have a good home receiving setup, but have spoken to a local ham repeater owner about applying for a free receiver and plugging it into an unused site where we wouldn't need a big investment in transmission line, etc. Was thinking that it might make good publicity for hams--helping make the info more available to small boaters who could use their mobile devices w/Internet instead of buying a high dollar plotter.

But the interest I'm expressing in this thread is for something that would work for my own casual mobile/portable use. There are lots of holes on the James River--particularly near Richmond.

The nearest online receiver at this point is actually on a buoy, maintained by local college students who are also taking tidal and other measurements and sharing with NOAA.

73/Allen (N4JRI)


Sent from my iPad using Tapatalk
 

n4jri

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#10
Keep in mind it's not about covering a WIDE AREA, the local coverage is more important, which is where the site you mentioned has vessels drop off just up the river.



BTW if you click on the link for that site, you will see it indicate "Low Coverage"

but they do cover about 95 sq/mi



As to navigation via the internet, a boater should invest

that would be like relying on a cellphone instead of a marine radio [IMHO ]:roll:


Yes, the buoy is out of the water for maintenance, sitting in the marina. Hopefully back to full power soon. I myself can't even provide low coverage--I live about 6 miles from the city. Just looking for something I can use in the field--and standing by to assist anyone near the river who is interested in increasing coverage.

As for iPhone use, some small boaters don't even have a radio. But they might enjoy the benefits of seeing what's out there with a $5 app.


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#11
Hi Guys,

First-time post and thought I would jump in with my recent new experiences with AIS. I have just set up my own AIS station here in Adelaide Australia with compliments of Marinetraffic.com. They included everything required including receiver, antenna and 10Mt of cable with connections.

I applied with MT knowing that there were other stations within my vicinity, but they were only too happy to take me on board.

My station is https://www.marinetraffic.com/en/ais/details/stations/4365/_:8e628a30aaa2dcdcbcc90b848dfb9cf8

As you can see from my stats I'm getting plenty of coverage, but I'm not far off the coast and do have a direct line of sight to the sea from my kitchen window, and I'm also about 30Mt ASL.

There are a couple of questions I would like to ask about antennas but I don't want to hijack this thread and I'm not sure if I should be asking here or in the amateur antenna forum?

Cheers,
John :cool:
 
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#12
There are a couple of questions I would like to ask about antennas but I don't want to hijack this thread and I'm not sure if I should be asking here or in the amateur antenna forum?
Just create a thread in the Marine forum. AIS is not amateur-related.

Probably the best thing you can do for your AIS station is to find a tight VHF bandpass filter. This can be tricky and newer models tend to be pretty expensive; however, you can find all sorts of models on E-Bay. The downside is they usually have too much bandwidth.

If you keep searching you'll probably find a used filter for a fair price. Ideally, something between 155-165 Mhz would be ideal. Anything tighter than that would be likely be very expensive.

You can buy a tuned AIS antenna from DPDProductions.com but the filter is a better investment.
 
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#13
This'll probably get split off into it's own thread, but I'll add a bit…

The kit that MarineTraffic.com sent out included (when I got mine) a halfway decent 5/8th's wave antenna that they had measured and marked to be resonate on the VHF marine spectrum.

I put it up until I could get a better antenna, however that was a couple of years ago and I never got around to replacing it.

Direct line of sight is good. I've got mine about 900 feet above sea level. Currently I'm picking up ships a bit over 700 miles out. When atmospheric conditions are right (local summer time), it works really well due to tropospheric ducting. In the winter when the ducting goes away, it drops down to 70 mile range.

One thing I did do is to use better coaxial cable. Not for any reason other than I had a piece of LMR-600 up there from another project and it wasn't doing anything. It also allowed me to run just the amount of cable I needed.

As for interference, I haven't had any issues with mine. It's on one of my tower sites where I have a couple of 100 watt VHF public safety repeaters, an 800MHz conventional repeater, and a node for a cellular DAS system running all the major carriers on all their bands.

So, getting yours up high will certainly help, but tropospheric ducting might help it out.

https://www.marinetraffic.com/en/ais/details/stations/3455



On the flip side, I had an ADS-B station up there at the same location. Worked great until Verizon added their 700MHz LTE radios. Then I dropped from around 380 mile range to about 15. Ended up moving to another site to get away from Verizon. Filtering didn't address the issue.
 
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#14
Just create a thread in the Marine forum. AIS is not amateur-related.

Probably the best thing you can do for your AIS station is to find a tight VHF bandpass filter. This can be tricky and newer models tend to be pretty expensive; however, you can find all sorts of models on E-Bay. The downside is they usually have too much bandwidth.

If you keep searching you'll probably find a used filter for a fair price. Ideally, something between 155-165 Mhz would be ideal. Anything tighter than that would be likely be very expensive.

You can buy a tuned AIS antenna from DPDProductions.com but the filter is a better investment.
Hi devicelab,

All this new tech I'm still learning about and now I can add bandpass filter to the list. :)

I was looking at the DPDP website last week where he had an LP (?) tuned array which he claims is better than a Yagi, why I'm not sure, but now there is no reference to the tuned array whatsoever and all he currently has is a couple of tuned vertical sticks?

Cheers,
John
 
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#15
Hi mmckenna and thanks for the reply.

This'll probably get split off into it's own thread, but I'll add a bit…

The kit that MarineTraffic.com sent out included (when I got mine) a halfway decent 5/8th's wave antenna that they had measured and marked to be resonate on the VHF marine spectrum.
The antenna they supplied me was a GP 3-E so I'm not sure if we got the same or not?

Direct line of sight is good. I've got mine about 900 feet above sea level. Currently I'm picking up ships a bit over 700 miles out. When atmospheric conditions are right (local summer time), it works really well due to tropospheric ducting. In the winter when the ducting goes away, it drops down to 70 mile range.
You certainly have the height to your advantage that's for sure. Yes we are in the middle of winter here at the moment and I have noticed my area of coverage drop off significantly at night.

One thing I did do is to use better coaxial cable.
My cable run is 20 Mt long so I replaced the supplied cable with a more heavier duty cable suitable for the longer run.

There is another AIS station slightly South of me that seems to have far greater area coverage than what I get and he also gets attributed at marinetraffic as the station which identifies the vessels in the Port of Adelaide to the North of us, not sure why this is really?
https://www.marinetraffic.com/en/ais/details/stations/1511/_:8e628a30aaa2dcdcbcc90b848dfb9cf8

I can see I have a lot to learn. :confused:

Cheers,
John
 
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#16
Further to my look into bandpass filters, is this the thing I'm looking for or are there other alternatives?
https://www.antennas-amplifiers.com/162mhz-ais-preamplifier-bandpass-filter

Also as you scroll to the bottom of that page there is a review from Leigh VK2KRR who also has this company's 4 X 11 element array. Mind you his set up is on a mast etc and I'm not sure I could imagine a single array on my house roof given the length of the boom?

Cheers,
John
 
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#18
Further to my look into bandpass filters, is this the thing I'm looking for or are there other alternatives?
https://www.antennas-amplifiers.com/162mhz-ais-preamplifier-bandpass-filter
That's a LNA (low noise amplifier) + bandpass filter. The amp looks to be fairly generic but the bandpass filter is tight and looks like it would be worthy. The price suggests it may not be of super high-quality (a commercial version would probably run you 300 Euro or more) but it should work fine. (Again you can verify it's effectiveness with a VHF antenna analyzer.)

Remember, this LNA should be mast-mounted or very close to the antenna feedpoint. I see the AIS antenna uses a UHF connector, so you'd want a short run (< 3m) UHF to N into the LNA and then coax from the LNA into the house. You also need to provide 12v DC to the LNA as well.

You don't *have* to use this at the mast but it'll be more effective there.
 
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#19
I was looking at the DPD website last week where he had an LP tuned array which he claims is better than a Yagi, why I'm not sure, but now there is no reference to the tuned array whatsoever and all he currently has is a couple of tuned vertical sticks?
Yeah you're best bet is to email Dave and see if he can build you a proper LP antenna. The LP is a log periodic and they generally work across a broad range -- such as 75 Mhz thru 1000 Mhz. Yagi antennas tend to be more frequency specific.

It depends on the application of course but a tuned Yagi would be nice for AIS; however, I would have to look at the numbers because it would depend on a lot of factors.

The yagi antenna is like a narrow-beam flashlight and might be too focused. I don't recall how far you were from the coastline but if you're too close then the Yagi would certainly miss a lot of signals. It might pull in more distant ships along a specific path but you'd likely ships that were out of your line of sight.

If you're fairly close then I would stick with your current antenna for now. I think the LNA would be a great investment (as would a VHF antenna analyzer) for maximizing your current setup and verifying your antenna efficiency.
 
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#20
The antenna looks to be fine as long as you've tuned for 162 Mhz AIS. If you really want to be picky you can borrow a HAM's antenna analyzer and measure it to verify it's frequency center.
Hopefully, it's tuned properly, I just followed the instructions and set it to the specified length.

Gee looks like I will have to join an amateur radio club.

Cheers,
John
 
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