No sound using Ubuntu.

[olddave]

HI, I'm trying to use an RTL.SDR RTL2832U R8202TU TCX) + Bias T+HF

Via GQRX 2.15.18

The display works ok, but no sound at all.

Volume is turned up.

Sound works ok on other applications. So the computer is ok.

Any ideas, anyone.

Dave.

[Charlie Hotel]

Hi Dave

You may want to check a demodulator is selected (AM, FM…) and the squelsh is set to the minimum level.

Also set AGC to something else than « off ».

Cheers

Bernard 

Le 17 févr. 2024 à 19:52, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[olddave]

Hi Bernard,

Thanks.

I have demod on Wide FM, AGC on Medium and squelch at -28.0 db .

No different.  (I'm looking at the Broadcast FM frequencies)

Dave.

[Charlie Hotel]

Then next comes Paul’s advice!

Although -28 for squelsh does not look

Good… -160 would be better !

Cheers

Bernard 

Le 17 févr. 2024 à 21:58, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[olddave]

Gone to -150 (as far as it goes) no different.

Any other hints ?

Dave.

[olddave]

Just let me throw in a couple of other things.

Receiver options -272.700Khz

Hardware frequency 9988.000 Khz

Does that look right ?

[Charlie Hotel]

Also:

There is an audio device selection in the same window box as the sdr device selection. You may Check that.

And there is an audio spectrum (bottom right if enabled).

If the spectrum ok and no sound its a routing problem.

If nothing on the audio spectrum: its in gqrx!

Bernard 

Le 17 févr. 2024 à 22:09, Charlie Hotel <charli...@free.fr> a écrit :

Then next comes Paul’s advice!

[olddave]

The audio spectrum is showing33.3 dB (nearly full scale).

I have the Audio Output on default. Sample rate 48K

Looks like it's time for a coffee and a head scratch.

Thanks for your help so far.

Cheers,

Dave.

[Charlie Hotel]

Hi 

9988.000khz is like 10Mhz, not 100MHz…

Offset looks OK.

Bernard 

Le 17 févr. 2024 à 22:22, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[Charlie Hotel]

BTW, there is a ‘mute’ button below the AF spectrum as well as a volume slider… on my system, that slider is at about 25% for reasonnable audio but that’s system dependant…

Also check IF and AF filter bandwidths just in case some is set to zero…

Bernard 

Le 17 févr. 2024 à 22:41, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[olddave]

Hi, Bernard,

Well, I have sound.  Took the machine back off, waggled plugs.  Seemed to work.

But while I'm here.

I'm new to GQRX (and Ubuntu),  At the moment I am listening to 98.9 Mhz. And this shows at the top of the screen.

But the Hardware frequency shows -295.7 Khz.  What doe this indicate ?

Also, are there any good tutorials for GQRX on the web.

Best regards and thanks for your help.

Dave.

[Leonard Mabele]

Hi Dave,

Is it possible to post some screenshots from your GQRX interface while you are running the above?

Also, I found this to be a great beginner's reference: https://www.amazon.com/Explore-Software-Defined-Radio-Satellite/dp/1680507591/ref=sr_1_6?dib=eyJ2IjoiMSJ9.0cRqNN4cBuB19FkZS3MqBAjRe78TsJDEjnZUc49njFzTFzH_q9JjMH-9yJtGYRBQgB0FvcOvCVL2DG3pKkdE8WEN-Lj6CaTsKzkQ3njA5Cg6VXDaFEDX49bS1KJ0Zvsg-py6MJYS9QgW4sj8l7d9PWmmglQ1tCZAJn9C0JKnhplRaYLY7h5qpe2ilJ1OQcIndFLy9TwsiA_WG6aqKqhEwBxhAx70fKIOf2TbtNnLy8I.6btZ_Sa2t2RZThCtcAh-sYbnRcDlgTm4wNFXYJ5mQos&dib_tag=se&keywords=rtl-sdr&qid=1708305098&s=books&sr=1-6

I have also attached another great reference I used a while back.

Hopefully it helps on both GQRX and Ubuntu for you.

Cheers

Leonard

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[Charlie Hotel]

Hello Dave

Glad sound is back ; it is much easier to listen to radio…

Normally, hw frequency should indicate the rtl dongle LO frequency and be the display center frequency .

The offset frequency should be where the demod sits in the converted bandwidth, so it varies between -fs/2 and +fs/2 ie about +/-1MHz or whatever the s’amplifie frequency is set at.

The main dial frequency is therefore HW freq+offset and is the frequency you are listening at.

For every day use, gqrx manages Hw and offset, but you can set them if you need to.

Basically, tuning HW changes things in rhe dongle and changing offset only affects the SW (gqrx) and is usually faster.

Cheers

Bernard 

Le 18 févr. 2024 à 19:54, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[Ersoy YILMAZ]

Do you have a DHMI device?
Had the same problem. Restarting ALSA helped me.
Try to test it with a earphone.
Most probably you will have sound :-)
And if you can use the VGA output.

If HDMI is connected, the "intelligent" system thinks the audio must be also diverted to thei HDMI channel/output.
I bought also a extra sound card and had always sound, even HDMI was connected.

--

[olddave]

Ersoy,

I have an HDMI socket on the computer, but don't have a monitor so equipped. Something I will be getting later.

Leonard,

Thanks for those links. Every bit of help is much appreciated.  (old dog learning new tricks).

Bernard,

I did discover that the computer doesn't have a built in loudspeaker. No big problem as I can easily use an external one.

You've all been very helpful with this problem.  On this computer I am running openSuse Leap. It works well for me, though I am really using it via the GUI and thus pretty much as one would use Windows. I'm still learning to use the terminal. But having used DOS in the past, it isn't all that different.; Just more detailed.

One question.

As I want to be able to use GQRX 'in the field', do any of you use Ubuntu on a laptop ? I hear it isn't such an easy thing to do. Or is it better to use a different Linux distro ?

Regards all,

Dave,

M1BZD

[Tim Finley]

Dave,

I have a RTL-SDR mounted to the back of the screen using double-sided 3m (so called 100 MPH) tape. I have a small USB extender I use when I need to use the dongle. Since I'm generally right under the transmit antenna, I use a wifi antenna on the dongle (I've also used a paper clip).

I have AppLauncher installed and use the AppImage for GQRX as it is the easiest way to keep the software updated.

The laptop is a System76 brand with the default Pop_OS! installed. Pop_OS! is basically Ubuntu, but tweaked by the System76 team.

I use my laptop to monitor radio stations that I am working on since there are many sites that don't have a simple receiver present. My only gripe with GQRX is the RDS seems to be the European RDS rather than the American RBDS and there's no way to toggle that. But it's really not that big of a deal.

The biggest problem I've faced with using Linux laptops has nothing to do with GQRX. There's a long standing issue with the way Linux utilizes sleep, deep sleep, and battery power management (citation needed). To circumvent this issue, I shutdown my laptop whenever I close the lid. This ensures it will at least power on when I need it. To my knowledge, every Linux distro suffers from this issue. I've been in the Debian camp for many, many years. So my experience is limited to Debian based systems.

To view this discussion on the web visit https://groups.google.com/d/msgid/gqrx/d93fe789-8325-4b57-afc6-dc8540049383n%40googlegroups.com.

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[Mister Mistopheles]

Hi olddave ,

One question.

As I want to be able to use GQRX 'in the field', do any of you use Ubuntu on a laptop ? I hear it isn't such an easy thing to do. Or is it better to use a different Linux distro ?

I have the Linux Mint on my Hamradio Laptop. That works well and the most hamradio Software is able to install and runs proper.

Not easy to install,but possible with Internet Help.

Or... You use the raspberry 4 . He works also well with gqrx and wsjtx and the other Software.

Some SW is easier to install....

73, from Karl oe3jag 

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[Charlie Hotel]

Hi Dave

I do run Ubuntu on an old laptop and it works ok, including gqrx, gnuradio and Arduino IDE.

You can just they it as a live distro from a usb stick before you install. If it fonds your hw (wifi, sound chipset…) the install will be fine, no risk in trying!

(I’m also a GUI guy !)

Have fun with gqrx, a great application!

73 de

Bernard F1EVY

Le 19 févr. 2024 à 15:39, 'olddave' via Gqrx SDR <gq...@googlegroups.com> a écrit :



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[olddave]

Plenty to be going on with there.

The laptop I am going to use is a HP 14 cm0506sa.  It was bought because it has Windows 10 installed and was intended for Cubic.  But it is a real pain to try installing anything on.  I will get it changed to (probably) Ubuntu. With Windows I stopped at XP' which is pretty bullet-proof.

Karl,

What is that object behind you ?

Tim,

Do you have any problems with electrical interference from your car with that set up ?

Leonard,

I'll try taking a few screen shots next time I use the system.  It's easy enough using openSuse, but I haven't tried on >Ubuntu.

Anyone here using the RTL.SDR as a spectrum analyser ? For normal electronic use.

Dave,

M1BZD

[Richard Bown]

Hi, rather than Ubuntu , I would really recommend using LINUX MINT, it uses ubuntu libs, but ,it does not suffer from the Ubuntu

habit of early release of updates , which break things.

It is more up to date than debian, which I personally Hate .

Linux Mint installs without a problem and has a very good user forum

HTH

Richard G8JVM

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[Mister Mistopheles]

Hi Dave,

 Karl,

What is that object behind you ?

Which background object do you mean ?

By the way... I agree, Mint is ufb !

And the raspberry as well !!!

@Richard: My last Windows is also XP. From now on I continue with Linux Mint...

73, Karl oe3jag

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