Maximum Receive Range?

[54901 - Jim]

I'm landlocked ... closest ships would be 50 miles (80km) from me.  What is the effective receive range for ShipTrax?

Thanks!

Jim

[AirNav Development]

About 50 miles. But it will have a real-time network just like RadarBox so you could see ships being tracked at your location.

[54901 - Jim]

Thank you!  Not that I need yet another hobby, but I'll be interested in seeing the new product when it's released.

Jim

[jannuh]

Normal AIS range from coastal area's will be around 35 nm (outside antenna on roof).
Harbour area's gives a lot less coverage, if interested in inland shipping (only active in netherlands/belgium/germany/austria/hungary) make abt. 15 nm of the coverage area.

[tarbat]

I guess the network feature will be very important for ShipTrax, given the limited AIS reception range.

[jannuh]

I upload AIS data, beside to Shipplotter, also to MarineTraffic.
Coverage area:
http://www.marinetraffic.com/ais/default.aspx?zoom=7&centerx=5.9871&centery=51.2591&oldmmsi=263

MarineTraffic is the cheapest way to be involved in AIS, in the way you get free software to upload data to them, you just need a scanner with discriminator output and their free software.
More info on dicriminator output: www.discriminator.nl (in dutch and english)

You will notice when viewing on marinetraffic that the AIS freq. in VHF are much more under influeance of VHF ducting (tropo conditions) then the ADS freq. are.

My own all time DX is 900 nm, but in the Med and PG (Persian Gulf) 300-500 nm is quit common.

[tarbat]

you just need a scanner with discriminator output

Easier said than done.  I tried doing the discriminator modification on my Yupiteru MVT-5000, without success.  I suspect I fried the IC when trying to solder the 10k resistor onto pin 9 :(

I'm waiting to see what the Airnav receiver hardware is like - something that gives TCP output would be best for me.  In the meantime, I use the ShipPlotter network.

[tarbat]

Maximum range I've had recently on AIS is just over 60nm.  Okay, that was a SAR helicopter, but it demonstrates the range you can expect with clear line-of-sight.

That's with an antenna in the loft of our bungalow.  I could probably get better range with an external antenna with a bit more height.


http://www.flickr.com/photos/tarbat/5243702576/sizes/o/in/photostream/

Interesting to compare this to the "theoretical" maximum range predicted for targets below 1000ft (ie sea level):


http://www.flickr.com/photos/tarbat/5243233419/sizes/o/in/photostream/

[jannuh]

Hi Tarbat,

A SAR Helicopter ain't daily stuff on AIS, max. range has more to do with tropoducts.
My max range was abt. 300 nm within a tropoduct period.

Daily average max. (inland ships) is abt. 15 nm.

[tarbat]

Interesting observation comparing Radarbox and ShipTrax reception - both antenna are in the loft.  I've been tracking the SAR helicopter again this evening, and it dissapeared from both the Radarbox and ShipTrax reception at the same time, at a distance of 65NM and altitude of 5500ft.  I guess that is line-of-sight from my location.