Gqrx and Strange Behaviour

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Vincenzo Mone

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Aug 3, 2025, 8:16:39 AMAug 3
to Gqrx SDR
Hello Guys,
please anybody can help me to solve my problem?
I ma using GQRX v. 2.17.6 with Ubuntu 25.04 in a VMware Machine.
Since last year all worked perfectly. I had to do qrt on satellites for about one year due to problems with my elevation rotators.
Now i am back again but noticing problems on GQRX i am noticing that when i satrt GQRX i hear the audio with intermitting for about a minute or less then the audio goes OK.
ALso i have noticed that the Top screen and the bottom screen of the gQRX are totally black and both slides: Plot dB and WF db are on the right side and inhibit so i cannot interact with them. As HW to listen i am using a FUNCUBE DONGLE PRO PLUS.
Here attached is how i see the program wqhen i launch it.
Please anybody can help me to solve the problem?
Thnaks 

73's de Enzo IK8OZV

GQRX.png

Dave Baxter

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Aug 4, 2025, 4:10:08 AMAug 4
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Hi.

Has your system updated since the last time GQRX worked?   I do know that later Debian (12) based systems have a serious problem, even the repo supplied version fails to run correctly.  (As here on LMDE 6.)

I also found in the not too distant past, that support for some of the FCD devices was removed.  :-(

I've also failed to get it to build from source too, with the usual chain of unresolvable dependency problems, probably fixable, but there are not enough hours in the day, even for even us retired types to wade through all that.

I'm guessing the author's have moved onto other things.  Shame really.  That's the peril of using a relatively specialised open source application.

There are other SDR software options for Linux users, but I'm not sure how many still support the otherwise excellent FCD's.   It all seems to be going proprietary using dedicated Windows app's for specific SDR hardware these days.

Hope you find a working solution.  I haven't yet, too many other things going on here.

GQRX v2.17 is available (at https://github.com/gqrx-sdr/gqrx/releases/tag/v2.17 )as an app-image as well as sources, but that doesn’t seem to let me specify any other "device" than it currently lists, and that is a very small selection.   I can't screen scrape from it either.  :-(

Again, no time just now to explore other options.

73.

Dave G8KBV.

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Robin Gape

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Aug 19, 2025, 9:50:30 AMAug 19
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Vincenzo, Dave,

there is an issue with the 2.17 series of AppImages, concerning, IIRC, some changes that are being made with hardware support in GNU Radio.

For the benefit of humanity, I've just tried a series of tests—whilst waiting for something else to finish—of various releases of AppImages.

The tests are performed on a recent installation of Ubuntu 24.04. The udev files to support recognition of the hardware will have come from a separate installation of GNU Radio. The attached note from 2019 contains a suitable udev rule, and instructions for installing it.

The tested versions of GQRX Appimage that worked were:

  • 2.16
  • 2.15.10
  • 2.14.5
  • 2.13

When selecting FCD Pro+ (FCDPP) GQRX would complain about ALSA, and usually refuse to start processing. However, on a restart of the AppImage, then processing would start and all would, apparently, be well.

Version 2.17.7 did not work correctly. It also complained about ALSA, whether the FCDPP was selected from the input device menu or simply on a restart. [This is probably due to using the most recent version of GNU Radio.]

One virtue of the AppImage is that it carries its necessary support libraries within itself. Thus multiple AppImages can be installed at the same time.

HTH

Robin, G8DQX (who has been using GQRX the FCD, the FCDPP, and various other bits of RF hardware for quite a while now!)

On 03/08/2025 13:16, Vincenzo Mone wrote:
FCD on Ubuntu 2019 version.pdf

Vincenzo Mone

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Aug 19, 2025, 10:40:45 AMAug 19
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Robin,
i have tried to instal the version 2.16 but have noticed the same issue
Please any Advices?
Thnaks

73's de Enzo IK8OZV
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Dave Baxter

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Aug 19, 2025, 11:28:02 AMAug 19
to 'Roger David Powers' via Gqrx SDR
Robin.

As you say you use the FCD (Not Pro) as well as the FCD Pro+.   What is the secret sauce to get the plain (original) FCD working?   I've failed to achieve that with the last full install (from OS repo) and a later AppImage.

(Sorry, but I don't have the version info to hand for that instance of GQRX.)

That is on LMDE6 a Deb' 12 derivative, in full OS feature and security update support.

Similarly, I'd like to get my original SDRPlay working again too, but trying to build from the sources resulted in (mostly) lots of QT issues, even with (eventually) the correct version library's installed.

Everything was working well with LMDE5 (where I built it all from source, linking with the SDRPlay API, and the SoapySDR libs too) but after the upgrade, none of the GQRX stuff I had/have works, or can be made to work (or build.)

I know things advance over time, but many of us silent types out here like stability rather than being at the bleeding edge.

AppImages are OK, but I (and others) find it near impossible to get what's inside the Appimage, to use hardware devices etc, outside of that environment.

Fun eh?  Not!

73.

Dave G8KBV 


If it aint broke, hit it harder.

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Robin Gape

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Sep 3, 2025, 5:06:56 AM (4 days ago) Sep 3
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Dave, Enzo,

1) knowing the version of a GQRX AppImage is essential!

2) a properly constructed udev file is also essential, as noted in the attachment to my earlier email https://groups.google.com/g/gqrx/c/8EbZw2GT4X8/m/ZBiu9K3wAQAJ

To check point 2), install package qthid-fcd-controller, available in Ubuntu but not, AFAIK, in Mint. Not sure about LMDE.

HTH, 73,

Robin, G8DQX

Dave Baxter

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Sep 3, 2025, 9:17:42 AM (4 days ago) Sep 3
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Hi Robin.

Thanks for the information and advice.

The AppImage of GQRX I've tried, is 2.17 (and the earlier 2.16) both for x86_64 architecture.


Re the FDD.

qthid-fcd-controller though not available using apt install.  IS available via synaptic, as version 4.1-6

This as earlier is with LMDE 6, a Deb' 12 derivative.  (In essence, Mint minus the Ubuntu influences.)

Synaptic installed it, and a couple of lib's (with no errors or warnings) and it shows up in the "Accessories" menu as two entries.  Both launch without issue.

"qthid" who's properties say:-  "full support for the Funcube Dongle API available with firmware 18f or later"

And "qthid-2.2", where the properties show :- "limited support for devices with older firmware"

Both versions launch, show different UI's, but (as yet*) don't identify any FCD.

* Probably as I've put them somewhere in a "safe place"! 😳

(I "presume" I need the -2.2 version for the original non + FCD, when I find them.  Yes/No ? )

(I did find a web page with sources, but that was by accident, and also accidentally closed the page before I'd bookmarked it!  There is a sourcecforge project, but that seems stuck/abandoned at V3.x .)

I have several other rules installed in  /etc/udev/rules.d  for other shack hardware.  (Interfaces to other conventional radios and some other non radio things.)  As well as those for the FCD's.

    20-FCD-FCDPP.rules

    99-shack.rules

The shack rules all work fine, so I (again) "presume" the FCD-FCDPP rules will be found when I find one of the things again, and plug it in!

When I find one, I'll try again and report back.  Hopefully with a dmesg capture of what happens when one is inserted in a vacant USB hole!

Hope the above makes sense, and perhaps a little bit of help to others.

73.

Dave G8KBV.

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