Rasp Pi, funcube dongle and cleaning a Wfax file

[conachair]

Might be one or two on here with a fun cube dongle pro plus usb radio receiver..



Great little receivers, and the good news is someone has tweaked some software so it will work on a Raspberry Pi. Pi 3 anyway, which I use.
http://gqrx.dk/download/gqrx-sdr-for-the-raspberry-pi
It's on the edge but largely stutter free if you keep the FFT refresh to very low or off and narrow filters push it a bit far. I've a hifiberry hifi amp as well so the Pi is nav system, music system and now wfax receiver as well. Great having a quality receiver from near DC to 2GHz running on SDR over the boat speakers, control works from a laptop over VNC so you can recline and surf the airwaves


So long shot but you never know....
The dongle can record a wfax transmission straight to file then with some changes to the bit rate the weatherfax plug in can import the file into opencpn - so the question ->
Is there anything can be done in audacity to clean up the audio before it decoding it in opencpn? Or maybe SOX?

Have to say, openplotter on a Pi 3 is nothing short of astounding!

[conachair]

Well not sure any of that made much difference.
Tried normalising and compressing, made big difference to the displayed wavefrom in audacity but the displayed imaged looked pretty much the same in opencpn.
Main thing is it WORKS!!

No idea what this is, maybe ice or something and the coords were from some other chart so it's in the wrong place but the main thing is the image is usable and this in a boatyard surrounded by masts - be a better image out at sea. Yay, been after something like this for ages rather than have to dig the laptop out and plug in into the ham radio, so now just a couple of mouse clicks to record a weatherfax. Might be able to automate it but maybe not, you can load gqrx probably at set times from node red but you might have to manually hit the play button.
Fun cube dongle ain't pennies though, but then it's being a FM/AM shortwave receiver as well for day to day use and great fun for listening in on ham bands or the marine vhf/hf frequencies. All in all a good day, the mighty Pi does even more!

[ohgary]

Fun cubes are nice but a bit pricey. Might just look for the USB-T dongles, They will work with gqrx just as well and typically cost under $20.

[conachair]

Originally Posted by ohgary

Fun cubes are nice but a bit pricey. Might just look for the USB-T dongles, They will work with gqrx just as well and typically cost under $20.

Cheap and fun but the rtl dongles only receive from about 50Mhz so no good for receiving weatherfax. Upconverters available on ebay but the price difference isn't so great considering the difference in quality. People have had success receiving sat images with them though.

[conachair]

Now I'm sure a while ago I had a wfax decoder which could move just sections of the image if the audio stuttered half way through and the sync went out, can't find it now - anyone know?

[Paul Elliott]

The RSP1A from SDRplay (https://www.sdrplay.com/rsp1a/) is slightly less expensive than the Funcube Dongle Pro+ (FUNcube Dongle | A radio that's out of this world!), and in practice works very well.

While the Funcube is smaller and cuter than the RSP1A, I find the Funcube to be a bit mechanically fragile, and unless I have the Funcube safely tucked away where it can't be moved, I end up using a USB extension cable with it to keep from stressing and breaking the USB connector-to-board solder joints. I also put a short SMA jumper cable on the Funcube to protect the SMA jack.

The SDRplay unit is much larger, but the packaging is more robust.

[conachair]

Originally Posted by Paul Elliott

The RSP1A from SDRplay (https://www.sdrplay.com/rsp1a/) is slightly less expensive than the Funcube Dongle Pro+ (FUNcube Dongle | A radio that's out of this world!), and in practice works very well.

While the Funcube is smaller and cuter than the RSP1A, I find the Funcube to be a bit mechanically fragile, and unless I have the Funcube safely tucked away where it can't be moved, I end up using a USB extension cable with it to keep from stressing and breaking the USB connector-to-board solder joints. I also put a short SMA jumper cable on the Funcube to protect the SMA jack.

The SDRplay unit is much larger, but the packaging is more robust.

Looks nice, 10Mhz bandwidth! Didn't see any drivers in gqrx, suspect the Pi would struggle with that bandwidth running signalk and broadcasting everything on it's wifi access point - it just copes with the FCD. But it does cope, which is great ! More and more stuff is getting made redundant by the Pi, hifi amp gone, ipod gone, now am/fm radio gone..

[conachair]

Originally Posted by Paul Elliott

and in practice works very well.
.

Do you use it for wfax onboard? What setup?

The Pi is coming along nicely here, record a transmission to file, a little SOX command easy to get to in node-red changes the sample rate, make it mono and copies to a temp folder then straight into opencpn with the weatherfax plugin. Sometimes a bit of stutter happens which messes the sync but usually it's OK with GQRX minimized, I need to see what else I can turn off to free up another crumb of processor power.

[flyingnut40]

Following; ;-)

[alansmith]

I have no background in radio transmission. But am very interested in hearing this. I have s boat in San Carlos. Will be out of cell tower range on Baja’s eastern side for weeks on end. Does it mean I could pick up my weather with a hifi radio and using Pine able to download the weather. Be gentle! I know next to nothing about Ham
Or hifi radio set ups.

I have a relatively new iPad which I run Navionics on. That is it.

[Paul Elliott]

(regarding the SDRplay, and the Funcube Dongle)

Originally Posted by conachair

Do you use it for wfax onboard? What setup?

The Pi is coming along nicely here, record a transmission to file, a little SOX command easy to get to in node-red changes the sample rate, make it mono and copies to a temp folder then straight into opencpn with the weatherfax plugin. Sometimes a bit of stutter happens which messes the sync but usually it's OK with GQRX minimized, I need to see what else I can turn off to free up another crumb of processor power.

On board I generally use Iridium for wfax images via saildocs.com, and I use the Pactor wfax demodulator with my SSB as a wfax backup. I have used the SDRplay and Funcube SDRs for wfax as an experiment, with various Windows PCs (laptop, fanless box, and NUC style). The wfax display programs are the OCPN wfax plug-in, and JVCOMM, and sometimes other wfax programs.

I would have to dig around to find the specific setup, and with Win10 the audio routing seems a lot more complicated, but I've always managed to make it work after some fuss. I did find that the small $199 Minix NEO (https://www.amazon.com/gp/product/B0749NR2KJ) worked fairly well for this, but the wfax / SDR combination was getting close to running out of CPU cycles. Here's something I posted about that on Sailing Anarchy: Sign In - Sailing Anarchy Forums (It's a prettty good thread, even if it's on a competing forum!)