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-   -   Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles ! (http://www.cruisersforum.com/forums/f134/fast-cheap-ais-using-20-rtl-sdr-dvb-t-sdr-dongles-84234.html)

Sailor_Hutch 17-07-2014 13:04

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Quote:

Originally Posted by larsed (Post 1586588)
Perhaps you're no longer interested, but I remembered having seen something about chipset/frequency ranges and finally found it:
RTL-SDR compatibility list v.2 [work in progress, please help!] : RTLSDR
rtl-sdr – OsmoSDR
As you can see the listed chipsets all cover the range you wanted blocked.

(had on my tongue to say something about legality, legitimacy and electronic communications after a.D. 2012, but I will not risk offending someone :devil:)

I'm not an expert either, but as far as I've understood the chipsets are only tuners with a high bandwidth. It's the software you apply to it that makes it tune, scan, decode or decrypt.

Thanks for the link!

Yes, the software is the rub. As more functionality is offloaded to the SD part of the SDR, it becomes less difficult to modify the overall operation, and frequency capability. Given a situation where there is nothing intrinsic to the hardware/firmware for purposes like forbidden frequency range blocking, it'd be mighty difficult to formulate a tamper proof system.

goboatingnow 17-07-2014 17:34

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Software defined radios are brilliant technology and will overtake conventional radio receivers. There are several well known SDR units on the market with open source software and hardware.

As to the legalities. Much of the western worlds telecommunications laws were written in a different era and there are many situations where illegal albeit harmless law breaking goes unnoticed, that of course doesn't make it legal !

As for building a radio, most laws do not ban the possession of radio apparatus, they forbid its use in certain areas. You can build what you like , it's when you turn it on , the trouble starts !

Dave


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Jacekpio 18-07-2014 07:26

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Hi Lars,
unfortunately I had not enough time to answer questions from Boat_alexandra this week. I will do it on monday - right now it is no possible to check my dongle model and so on.
Thank you for your comment.

Jacekpio 18-07-2014 07:29

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Quote:

Originally Posted by boat_alexandra (Post 1584683)
The plugin has no manual.

What operating system, which dongle do you have and which decoder are you using (gnuradio or aisdecoder) ?

Thank you for your answer, I will check all needed details on monday. Have a nice weekend

xynium 12-08-2014 12:59

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Hi,
https://sites.google.com/site/f4eyuradio/ais-decoder
This has a direct conection for Marine Traffic or OpenCpn.
Pete.

sbfreddie 12-08-2014 14:06

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Hi Guys:
I just wanted to say to Sean thanks for the code to make this $20 device work so well on my Cubietruck.
I'm getting AIS signals from up to 147 miles away!!!!
With OpenCPN running and the RTLSDR dongle receiving and decoding AIS signals, and receiving GPS, it only uses about 20-30 percent of the CPU's available power.
OpenGL-ES is enabled and working very well.

Thanks,
Freddie

boat_alexandra 22-08-2014 22:58

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
aisdecoder uses only 1/10th the cpu as gnuradio, but I would like to compare the two for range as gnuradio may implement better filters.

AISFan 22-10-2014 22:25

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
I have developed a similar rtlsdr AIS receiver for rtl2832u in Windows. It uses all available digital processing techniques I know. If you want to try it, you can give me a message. I am a fan of AIS and an engineer in wireless communication. I am not allowed to post a link here.

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boat_alexandra 23-10-2014 00:28

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Why can you not post a link?

Do you have the source code available? If so, then it can be integrated into the rtlsdr plugin for opencpn, and easily tested alongside aisdecoder and gnuradio.

Basically we want the software to use little cpu, and decode as many ais messages as possible (noisy signal) as well as ideally automatically calibrate the sdr dongle, and receive both ais A and B channels at the same time.

AISFan 23-10-2014 01:07

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
The kernel source code is not available. It runs in two power comsuption modes. The lowest mode consumes less than 3% cpu load in my computer. The full version supports all A/B channels and all 27 types of AIS messages with NMEA0183 outputs. lt currently runs in Windows, Linux, and Android systems. It runs in X86 and ARM platforms. I am considering making the one channel lite version free to all people. In my test, the lite version is powerful enough for normal users. Again, I cannot post a link here.

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rgleason 23-10-2014 01:23

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Aisfan - I am sure you know this is an open software forum. What is your purpose here if you can't help? Do you have any useful suggestions or techniques. Can you help improve our program in some way?

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AISFan 23-10-2014 01:41

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
I agree with what you said. At less, it helps people use dongles with opencpn.

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rgleason 23-10-2014 02:01

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
http://ca.linkedin.com/in/allanisfan Isfan Solutions and author of slideshow Them=Us. A good force. -- You should hire Sean freelance. He is brilliant but very expensive for non open software. If you aren't serious don't even ask him.

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AISFan 23-10-2014 02:21

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
I am a small guy. I would better wait to use his open software.

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rgleason 23-10-2014 02:51

Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
 
Then give him some good referals. Tell them he is very busy. He is brilliant, though expensive for non-open software. He is ready to freelance, but don't ask if they. are not serious Thanks.

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