dl-fldigi on the Raspberry Pi 2

[Roel Kroes]

Hi all,

I am trying to build a pocket size, battery powered tracking station which I can use on my bike, and in my car. I am planning to use it for HAB tracking and other HAM related things.

Main components are:

Raspberry Pi 2
USB Funcubedongle pro+
dl-fldigi
small portable LCD screen
portable Yagi

I got dl-fldigi to compile and run on the Raspberry Pi 2 and basically everything is working now. But…. I do not get RTTY to decode correctly.

I made an Arduino RTTY transmitter which I tested with dl-fldigi on a standard laptop. This works fine. It decodes perfectly.

However on the Pi, RTTY is only decoding partially. Usually I see strings of 10 to 15 characters decoded correctly and then it is garbage. I know that RTTY is CPU intensive to decode but this might not be the issue here as CPU usage is only around 20%.

Anybody, any idea where I should look next?

Thanks!

Roel
PD7R

[Mike Axford]

Roel

How are you decoding the datastream from the FCD Pro+ into usable demodulated audio. Whilst the FCD Pro+ might appear as an audio device it's not a standard audio stream, You'll need something to convert the raw IQ samples it outputs into demodulated audio (usually done with something like SDR Sharp on windows or gqrx on Linux/Mac).

An alternative approach (although possibly not as sensitive as the FCD Pro+) would be to try an rtl-sdr dongle and rtl_fm (the newer versions have support for SSB demodulation). This should provide an audio stream suitable for dl-fldigi to use.

Regards

Mike

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[stuart....@catvog.org]

I have found that my the Funcube Pro+ needs a reasonably powerful (Windows) machine to run on.

My cheap laptop, a 2Ghz Celeron machine with 4GB, just will not run the Funcube properly at all.

[Roel Kroes]

Op zondag 4 oktober 2015 14:30:28 UTC+2 schreef mfa298:

> Roel
>
> How are you decoding the datastream from the FCD Pro+ into usable demodulated audio. Whilst the FCD Pro+ might appear as an audio device it's not a standard audio stream, You'll need something to convert the raw IQ samples it outputs into demodulated audio (usually done with something like SDR Sharp on windows or gqrx on Linux/Mac).
>

Hi Mike,

Thanks for your answer and tip, I will look into that. I might be doing it all wrong, I am not sure.

Currently, I use qthid to control the FCD Pro+ and set the correct frequency. Then I select the FCD Pro+ as an input device in dl-fldigi. I can see the datastream in the waterfall and it does decode parts correctly, 10 chars in a row or so and then it stops decoding correctly.

Regards,

Roel
PD7R

[Roel Kroes]

> I have found that my the Funcube Pro+ needs a reasonably powerful (Windows) machine to run on.
>
> My cheap laptop, a 2Ghz Celeron machine with 4GB, just will not run the Funcube properly at all.

I don't think that is an issue with the Raspberry PI 2. fldigi uses less than 20% cpu time when running. That should be okay.

Roel.
PD7R

[Wouter Weggelaar [PA3WEG]]

>
> Currently, I use qthid to control the FCD Pro+ and set the correct frequency. Then I select the FCD Pro+ as an input device in dl-fldigi. I can see the datastream in the waterfall and it does decode parts correctly, 10 chars in a row or so and then it stops decoding correctly.

You are now using a "hack" to receive the IQ data as normal audio without knowing it.
What happens is that if you tune sufficiently close with the dongle to the actual reception frequency, the IQ data can also be seen as already demodulated data if you just take the I (or Q) channel, i.e. mono output.

various things can upset this hack, including mixing the I and Q together to form a mono signal, and so-called phase noise of the dongle. In any case, you probably now see a lot of DC content (zero hertz has a lot of power around it).

Like hinted, you can not really input IQ data straight into the dongle. you should use some demodulator to decode the audio first.

This makes me wonder: it should not be too hard to modify DL-FLdigi (or upstream FLdigi) to accept IQ streams? Maybe a nice project for someone?

73

Wouter

[Wouter Weggelaar [PA3WEG]]

> Like hinted, you can not really input IQ data straight into the dongle. you should use some demodulator to decode the audio first.

Obviously I meant input IQ data into DL-fldigi, not dongle...
I have too much FUNcube work going on at the moment I guess....;)

[Dave Baxter]

IIRC.  There was once a project to support simple SDR type input (I/Q inputs) from such things as SoftRocks and FCD's.  And that was for the regular Fldigi.  However, I've seen hide nor hair of that for a few years now, sadly.

It's all Open source of course...

That's how Dl-Fldigi came about anyway I suspect.

73.

Dave G0WBX

[Ian Gibbs]

Although it takes a long time, GQRX compiles fairly reliably so I
should just install GQRX and do it properly if I were you. If you have
any trouble, https://github.com/jacobzelek/rtl_sdr_kit should help
(you will will end up with some extra drivers for the RTL based
dongles, but that shouldn't hurt).

On 7 October 2015 at 19:54, 'Dave Baxter' via UKHAS

[Joe]

Has anyone here installed WSPR in a rasberry Pi?

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

[Oliver de Peyer]

I assume you mean the WSPR-X application?

I haven't tried installing this on a Pi, but I did try installing it on Linux in general. It didn't work. Basically it was written in Windows originally and then ported to Linux and MacOS (I checked with the author).‎ The MacOS version for instance works in a limited sense but has reference to COM ports etc which don't exist on a Mac - it's a straight port of a Windows feature.

With regard to Linux, I tried installing the distributions for various versions of Linux but none of them worked. It looks like it has only been ported for 32 bit Linux. But it still didn't work even when I set up a 32 bit Ubuntu installation just for WSPR-X! The installation process always fails at some point.

My advice is to find an old Windows machine and use that for WSPR-X. I have the greatest respect for the author of the software and he told me frankly that he just didn't have time to learn all the different OS and had just tried various porting environments from the Windows original.

Ol

2E0LVR

Sent from my BlackBerry 10 smartphone on the EE network.

From: Joe Sent: Thursday, 8 October 2015 16:04 To: uk...@googlegroups.com Reply To: uk...@googlegroups.com Subject: Re: [UKHAS] dl-fldigi on the Raspberry Pi 2

[Joe]

I had a page that showed it was dedicated to running it in a rasberry pi the whole page. now can't find it UG!

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

[Apostolos Kefalas]

Hello Joe,

I am running WSPR 4.0 r5489 on a Debian 8.2 (jessie) 64-bit for some
time now with no problems.

I have not tried to install it on Raspberry but I suppose it is straight
forward.

73
Apostolos SV1LJJ

On Πεμ, 2015-10-08 at 08:37 -0500, Joe wrote:
> Has anyone here installed WSPR in a rasberry Pi?
>
> Joe WB9SBD
>

[Oliver de Peyer]

‎How did you get it to install please?
I will check the version number that I tried to install when I get home today.
I can only reiterate that none of the WSPR-X linux packages would install. Some of the error messages seemed to concern Python.
Did you alter the MAKE file etc?

Ol

2E0LVR

Sent from my BlackBerry 10 smartphone on the EE network.

  Original Message  
From: Apostolos Kefalas
Sent: Thursday, 8 October 2015 16:54

To: uk...@googlegroups.com
Reply To: uk...@googlegroups.com

Subject: Re: [UKHAS] dl-fldigi on the Raspberry Pi 2

[namor rellek]

dear roel
did you finally get funcube an dl-fldigi running on your pi? i tried hours with a model 2 and and was unable to get the dongle working with any of the software options (we only need to visualize and listen to a certain frequency). any hints and directions very welcome ;o)

[David Lundberg]

Hi!

I'm working on getting fl-digi or similar (wsprd etc) working with rtl_fm but have run into weird results from usb/lsb-mode. Can't get proper usb-audio yet. Working on finding out why.

Kind regards,

// David