Unintelligible and very low audio

Ve3uky
Posts: 16
Joined: Tue Jan 28, 2025 5:23 pm

Unintelligible and very low audio

#1

Unread post by Ve3uky »

I have posted this message on the Kenwood 570 group on Facebook but I thought that I would do the same here as it may be a software rather than a hardware issue.

I'm attempting to set up a panadapter display using an RTL-SDR dongle and SDR Console. I tapped the IF signal at CN3 as described in a couple of YouTube videos. This tap connects to the dongle via an SMD connector. I've downloaded SDR Console and it appears to be running well. I set the software to accept an IF signal at 73.05 MHz. I'm running OmniRig for CAT control (it's working well).

However, I'm not getting any intelligible audio in the Console. I hear an extremely slight hint of a voice, but it is garbled and unintelligible. The software appears to recognize the signal, as there are spikes in the spectrum but no real audio. I do hear threshold static, which I can vary in volume by adjusting the volume levels in the software.

I've tested the dongle using an antenna and it receives well. I originally attempted to set it all up on a Windows 7 based computer, but when that didn't work, I did it all over again on a Windows 11 computer, thinking that it was a Win7 issue. But I got the same result on the new computer.

I systematically checked every adjustable parameter in the software that I could find (which took most of a day) but to no avail. I have toggled “Invert Spectrum” and have adjusted the bandwidth to a wider parameter on the advice of a fellow ham.

Any suggestions?

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KA1GJU
Posts: 366
Joined: Tue Aug 11, 2020 2:16 pm

Re: Unintelligible and very low audio

#2

Unread post by KA1GJU »

This guy uses 72.6127 for the SDR frequency:



73 Kriss KA1GJU
73 Kriss KA1GJU Home of the KA1GJU Super Station SDRC Servers in NH, USA (FN42mw, FN43na, and FN42lt)

Ve3uky
Posts: 16
Joined: Tue Jan 28, 2025 5:23 pm

Re: Unintelligible and very low audio

#3

Unread post by Ve3uky »

Oh... OK I'll try that this evening. Thanks!

Ve3uky
Posts: 16
Joined: Tue Jan 28, 2025 5:23 pm

Re: Unintelligible and very low audio

#4

Unread post by Ve3uky »

Hi Kriss. Well I had high hopes and tried that different IF, but it did not work for me. I'm listening to the voice that I'm hearing via the software and it's very similar the the effect that you get when you listen to 50 meters on USB rather than LSB. It's kind of Donald Ducky. And there is a whistle of sorts mixed in with the audio. It's a mystery.

jdow
Posts: 1025
Joined: Mon Aug 10, 2020 8:17 pm

Re: Unintelligible and very low audio

#5

Unread post by jdow »

Just for jollies try IQ inversion. On the definitions panel down just above "Save" is "Invert spectrum". That might do the trick.
{^_^}

Ve3uky
Posts: 16
Joined: Tue Jan 28, 2025 5:23 pm

Re: Unintelligible and very low audio

#6

Unread post by Ve3uky »

Hi jdow. Thanks for your comment. I've tried inverting. It didn't work.

jdow
Posts: 1025
Joined: Mon Aug 10, 2020 8:17 pm

Re: Unintelligible and very low audio

#7

Unread post by jdow »

Well, with the images posted on your second posting for this question you're not going to get useful reception. Switch to LSB. Tune until it sounds right. Ignore the frequency. Just tune until it sounds right. If LSB allows you to tune to get good audio, ignoring the frequency indications, then you do want to invert the spectrum. Be sure you save the definition again when you make that invert spectrum change. Otherwise it will get lost. You MAY have to alter the SDRC center frequency setting. Worst case you may need to use different settings for USB and LSB. (That's a arithmetic thing for some radios.)

{^_^}

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