Ship Plotter Software, And AIS Questions

[BOBRR]

Hi,

A few questions, please:

Live about 25 miles due west of Boston.

Have lots of trouble picking up any marine broadcasts, but do occasionally.

I have no trouble at any time in receiving marine weather broadcasts on 162.550

So, I'm wondering:

Where do these broadcasts originate from ?
Wouldn't they be aimed solely out to sea ?
Surprised I'm getting them so reliably.

Would love to buy the AIS Ship Plotter program, but not at all sure I would receive any of the position reports, my being 25 miles from the coast.

Since I do receive the weather ones fine even at my location, do you think I "might" be able to get these AIS ship broadcasts also, as I imagine a ship's Tx antenna is omni, and possibly have a fair amount of power ?

What do you think ?

BTW: anyone here using the Ship Plotter software package ?
Opinions on ?

And, if you are using it, are you using the discriminator output tap from your radio ?
I have a Uniden 996, and a JRC NRD 545, both of which cover the applicable freq's.
But neither has a discriminator output jack (that would feed the PC's soundcard).
Not sure how I could handle this.

Any way to make the regular audio output work ?

Thanks,
Bob

 

[ka3jjz]

Bob there's a dedicated Yahoo group for the Shipplotter software, and that's probably the best way to find dedicated users of the software.

As to a discriminator tap - there are services out there that do this, for a fee (G&G, the Radio Doctor in Virginia, and no doubt others). However, I would bet that the easiest - and maybe the least painful - way to go is to get an el-cheapo old scanner that covers the marine band (many do) and put the tap in there. That way you don't void out the warranty of the 996....this is hamfest season after all.

By the way, if you're a ham and have a relatively recently-built 2 meter radio, the discriminator tap is often found as an unused pin on the mic jack. Then it's just a matter of wiring the correct mating plug. It's often referred to as a '9600 baud out' pin (due to the fact that it would nominally be used for TCP/IP ham packet operations).

I don't use the software myself, but the rap on it is that, for a hobby level application only, it's quite comprehensive and well thought of. Well worth it if you are interested in that side of the hobby. However, like most applications of this type, the better the antenna and scanner (yes, it's a system....) the better the results.

73s Mike

 

[jpryor]

Your best test would be to sit on 161.975 MHz or 162.025 MHz and listen for the data bursts from the AIS transmitters. These are lower power (12 watt) ship based transmissions, so your distance from the water may be a challenge. The ShipPlotter software does however allow you to share and see data from other users. I usually only see a handful of ships here on western Lake Erie, but the sharing feature allows us to see elsewhere. You will need to use a discriminator tap and possibly in your situtation a directional antenna may help if you pointed out towards to water.

 

[holyshipmon]

Ais

If you can pick up vhf from ships you can pick up AIS from those ships as well. You might not get 100%, it might be spotty, or the stars might align and you will see ships down in New Orleans. I know you die hard radio guys will cringe when I meantion a dedicated AIS receiver but if all goes well with your initial testing then you should consider one. I use a SR 161 from Milletech marine priced under $200 and shipplotter software. This is a very easy and inexpensive way to watch shipping traffic in my area. I also set up my software to share with www.shipplotting.com so that I can view my data on the internet from home or work. I am sure you'll have no problem and I hope to one day see data from your nearest port. Good luck.

Chris Shelby
www.shipplotting.com