New rtlsdr Plugin

[rgleason]

Thank you sbFeddie, piluso and LeoA. I have now downloaded and installed SDR# followed those zadig install instructions (which seemed to come up with the same results and drivers, even after deletion of the current one, and also followed SDR# instructions to get the db for the dongle. The results were inconclusive. Tried HDSR with same. The graphs are not good coming out of DVB-T+DAB+FM. It is a Realtek RTL2838.

So I then installed piluso's version of rtl-dsr plugin into Opencpn 4.1.602 and ran it.
It has different instructions and seems to be a little smoother operation when getting the correction, however the first dongle failed again with -98. I am running the second one now and if it fails I am in the market for a new and better one. I don't think these are working correctly.

Any suggestions for a good reliable manufacturer and model available on Amazon? This will be the second purchase. I have messed with these two (second one sent by manuf when first did not work about 7 months ago.) for too long now. Need to start over.

Our VHF works fine so the antenna is good, that should not be the problem. I have installed the drivers a dozen times just this go round. I have learned three new programs to get the calibration number for the device and I have tried many configs for Opencpn connections with absolutely no sign of AIS working (Ais is left on in the icons of course.)

I've been blown out of the water on this simple task.

[rgleason]

PS: Second Rtl-sdr dongle came up with -98 too. Maybe I should try my Dell Laptop with Win7 and the VHF antenna on board to see if Windows 8.1 is causing the problem? --Perhaps not allowing the correct drivers to be installed?

[piluso]

The graphs are not good coming out of DVB-T+DAB+FM

Are you able to tune radio stations and hear audio from them using SDR# or HDSDR ? If that doesn't work, the AIS surely will fail too.
If you can hear radio stations through these programs, the rtl_fm and rtl_ais should work too, after setting a correct ppm value.Try first to get working these graphical tools, and then switch to rtl_fm or rtl_ais.
David

[LeoA]

I used this page to figure how to use and get my rtl dongle setup and working.

SDR# Quick Start Guide
To use SDR# for AIS, you will also need an ais decoder program to decode the radio signal. I use AisMon for this. If you can sdr# setup to receive fm or vhf stations, then you can use rtl-ais.

This is the rtl-sdr stick that I use
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I have 2 of them. PPM is 55 on one and 73 on the other

[rgleason]

Thanks Guys, I have been using

Are you able to tune radio stations and hear audio from them using SDR# or HDSDR ? If that doesn't work, the AIS surely will fail too.
If you can hear radio stations through these programs, the rtl_fm and rtl_ais should work too, after setting a correct ppm value.Try first to get working these graphical tools, and then switch to rtl_fm or rtl_ais.
David

SDR# and HDSR I can see a peak at 161,950,000 and can try to tune it but there are not various colors as shown in the Quick Start Guide, and I am unable to be sure about what the required -db calibration is supposed to be. I am new to these programs but have been following the quick start guide and it may be a user knowledge error, but I doubt it. Why would calibrating with the new version of rtlsdr_pi that pilous created fail on both of this manufacturer's dongles?

SDR# Quick Start Guide
To use SDR# for AIS, you will also need an ais decoder program to decode the radio signal. I use AisMon for this. If you can sdr# setup to receive fm or vhf stations, then you can use rtl-ais.

Yes this is a very helpful guide, and I followed it, reinstalling the drivers from zadig2.1.2.exe and reinstalling SDR# and then trying to follow the Calibration routine. It is well detailed and presented. I could not get anything conclusive. I ended up with something like -105db and Sean says when it is -98db it has failed.

Freddie - I am wondering now where the *.rules file should go and if I should try that. Is this script used when compiling or when we start rtlsdr_pi? I could not find the location of the old script so I don't know where to put it.

This is the rtl-sdr stick that I use
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I have 2 of them. PPM is 55 on one and 73 on the other

I am still going to think about this, and may try one more time, and post a pic, but I may get exactly that dongle on Amazon, just to be sure that all the heaps of trouble I've had are not due to the off market "DVB-T+DAB+FM" no name dongles.

[seandepagnier]

Originally Posted by sbfreddie

What does this mean? Does anyone know what I must do to fix it?

You probably need to add your user to the right group to have access to the dongle.

[seandepagnier]

Originally Posted by piluso

I've successfully merged the ais decoder into the rtl_ais binary, so there is no need to pipe data from one program to another.

I've added command line options for the aisdecoder part of rtl_ais (host and port) and I've added a feature from the original gnuais code for printing statistics about complete e incomplete messages (-S option). I see this feature very useful for coding an improved auto ppm discovery routine.

Great news.

Did you manage to code an improved auto ppm routine? Mine was basically garbage as it could only work if there is plenty of ais traffic and even then could take several minutes.

I believe if you use the wrong error correction you might receive channel A as channel B, or vice versa and then not get the other channel at all. This would be a pitfall if the routine were too simplistic, but perhaps you know from the message itself if it is channel A or B and can use this to detect this case?

Sean

[sbfreddie]

Originally Posted by rgleason

Freddie - I am wondering now where the *.rules file should go and if I should try that. Is this script used when compiling or when we start rtlsdr_pi? I could not find the location of the old script so I don't know where to put it.

Rick:
These lines are a small excerpt from a script to not only install OpenCPN & most of the Plugins, but also to prep the system before hand to work properly (user password, user groups, user privilege, udev rules, and all the prerequisites to build and install OpenCPN and the Plugins).

These rules go into /etc/udev/rules.d/80-rtl-sdr_udev.rules on Linux based systems. They are there to give the system information on which dongle has what characteristics and USB codes. Without them the dongle will not work because the systems' USB drivers will not recognize it as a valid device.
Like Sean says your user has to be part of the dialout group or your user will not have access to the USB device.

These issues are true for Linux, however I have no idea how this works on Windows.

Thanks,
Freddie

[sbfreddie]

Originally Posted by boat_alexandra

Great news.

Did you manage to code an improved auto ppm routine? Mine was basically garbage as it could only work if there is plenty of ais traffic and even then could take several minutes.

I believe if you use the wrong error correction you might receive channel A as channel B, or vice versa and then not get the other channel at all. This would be a pitfall if the routine were too simplistic, but perhaps you know from the message itself if it is channel A or B and can use this to detect this case?

Sean

Sean:
I use this program to check the PPM offset for all of my rtlsdr dongles:
RTLSDR Scanner | Ear to Ear Oak
I has a very good calibration section, all you have to do is find a nearby radio station that is broadcasting continuously (I use 162.425 MHz, its a marine weather broadcast) and it gives the offset in a matter of seconds. The only problem is all the code is written in Python. You might check it out to see how he does the calibration.

Thanks,
Freddie

[piluso]

Did you manage to code an improved auto ppm routine?

No, but this topic deserves an effort. The information about messages with errors is very valuable here because shows that something is partially decoded.

perhaps you know from the message itself if it is channel A or B and can use this to detect this case?

Yes indeed, the statistics are independent for each channel, and the messages come with a channel mark.
I think a calibration routine could be coded inside rtl_ais where the ppm value can be set anytime without restart, saving a lot of time.

I use this program to check the PPM offset for all of my rtlsdr dongles:
RTLSDR Scanner | Ear to Ear Oak

This is a great tool, may be including a graphical calibration tool in the plugin as Sean suggested, or pointing to some tutorials, could make easy get working the dongle.

Regards, David

[rgleason]

I have downloaded rtlsdr scanner. It appears to need python code in addition. Do I just install that to? 32 bit or 64 bit version?

Have checked the inf files in windows/inf. The most recent (sort by date) look for oemxxx.inf and open with notepad indicate that the zadig files installed successfully copyright 2010-2014 libusb (gnu lgpl) several times and they show the right source. Also file serupapi.dev.log shows that user frederick installled it. I assume I have device permissions though I have never seen this need or requirement on windows.

I found that the program rtl-ais.exe is looking for the "rules" file. Tried freddies and it was not satisfied. I don't think win has this requirement so maybe this is a linux program.

Have tried tunning rtlsdr_pi again and it failed again with -98

Might try rtlsdr scanner if can solve python request.



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[rgleason]

Dont have good wifi cant dwnld python yet. I've been thinking about the usb driver problem. The drivers and rtlsdr dongle seem to work with HDSDR and SDRsharp as there is definitely a peak at 161975000 and I think the calibration is -38db if I am doing it right.

So why doesnt the dongle appear to work under opencpn 4.0 or 4.1.602 rtlsdr_pi calibration or just pucking up ais?

SDRsharp install instructions said specifically that the usb drivers had to be installed under each application and went to great lengths to have the user do this installing lib files under the application directory.

I see all the rtlsdr_pi files are installed under plugins/rtldsr_pi/bin where the two programs rtl_fm and aisdecoder are located.

When I run
Rtl_fm -f 1619750 -p 35 -s 48k ! Piped to aisdecoder -h 127.0.0.1 -p 10110 -a file -c mono -d -f /dev/stdin

From the bin directory it runs. From the plugin/rtlsdr_pi directory it does not. Is this a problem?

Are the usb driver files needed in the bin directory? How would i determine if the correct ones are there?

Zidag2.1.2.exe does not have a user selectable destination diretory, but SDRsharp specifically states that the rtlsdr usb driver files must be under the application directory.

For windows users using opencpn and rtlsdr what dorectory would that be?

Are there any Windows users v7 or v8 (please be specific) that have this plugin working properly? with Good AIS aignals on a regular basis?

If so what is your setup? How did you get it working?
I am only interested in windows experience. Not linux, sorry but the permissions re devices are very different.

Thanks
Rick

[LeoA]

Rick, I am unable to get the rtlsdr.pi plugin to run from within OCPN, however I can receive AIS targets with sdr#, rtl_ais program furnished by piluso, and with pnais program mentioned earlier in this thread. I let Windows 8.1 install the zadig.exe drivers like any other usb driver.

[seandepagnier]

Originally Posted by LeoA

Rick, I am unable to get the rtlsdr.pi plugin to run from within OCPN, however I can receive AIS targets with sdr#, rtl_ais program furnished by piluso, and with pnais program mentioned earlier in this thread. I let Windows 8.1 install the zadig.exe drivers like any other usb driver.

It is very difficult to control external process correctly from windows without using window specific syscalls. For this reason I would like to see rtl_ais also built to be used like a library, then it can just link with the plugin and no external program would be needed.

I'm not sure how feasible this will be though if libusb is all build with mingw if you want to use visual studio to compile opencpn. It should be possible anyway, but requires also, some extra work.

For now I think I would like to focus on good autocalibration of the error code, but as for using the plugin with windows I cannot really support unless we switch to the mingw compiler.

[CarCode]

What about an AIS/USB stick? Might be easier for some people.
SEANEXX USB Receiver » Seaangel

Gerhard