Distortion in Audio When using BC-FM Mode - SOLVED

[AussieLand]

When using SDR-Console in BC-FM mode (listening to a local radio station) I get quite bad distortion. I have been through all the settings to try and eliminate this but to no avail!

I've taken a video which I've posted on youtube, however, the sound on the video is better (for some reason) than the sound heard from the SDR-Console

Any ideas anyone?

[jdow]

The video captured within SDRC can have cleaner audio than you hear if your audio setup is off. Try running audio level down both in the sound control panel and SDRC itself. Then run it up slowly. That music is, to me, pure noise so finding additional noise on it is difficult.

I notice you are using an RTL dongle. Set the sample rate to 2.4 ksps. The screen suggests you have it set to 3 ksps. Don't Do That. I've never seen one happy at 3 Msps. They tend to top off at 2.4 Msps. I also always run with the dongle AGC off in case you went in and turned it on. I also run at a gain around "19 dB" give or take a dB or two. Too little gain can introduce noise. Too much gain can introduce cross modulation noise. If you are using the wee little antenna that often comes with the dongles - rig up something better. A 5 or 6 inch spike is puny. And get the antenna as far from the computer as possible.

{^_^} Joanne

[G0OFE]

Hard to say from that if there is any distortion due to the style of music, as Joanne points out.

Try and upload a recording with something less harsh, or some speech or something.

[Simon G4ELI]

i would like to see just a screenshot so I can clearly see the settings, make sure the ribbon bar, Home panel is visible.

Please make sure you don't have any audio EQ enabled, but I don't see clipping so doubt this is the case.

I see the signal is not super strong, what's it like with a strong signal?

[AussieLand]

The video captured within SDRC can have cleaner audio than you hear if your audio setup is off. Try running audio level down both in the sound control panel and SDRC itself. Then run it up slowly. That music is, to me, pure noise so finding additional noise on it is difficult.

I notice you are using an RTL dongle. Set the sample rate to 2.4 ksps. The screen suggests you have it set to 3 ksps. Don't Do That. I've never seen one happy at 3 Msps. They tend to top off at 2.4 Msps. I also always run with the dongle AGC off in case you went in and turned it on. I also run at a gain around "19 dB" give or take a dB or two. Too little gain can introduce noise. Too much gain can introduce cross modulation noise. If you are using the wee little antenna that often comes with the dongles - rig up something better. A 5 or 6 inch spike is puny. And get the antenna as far from the computer as possible.

{^_^} Joanne

Hi Joanne,
Well, I couldn't find the sound control panel and I've set the sample rate to 2.5Mhz and bingo the sound is almost perfect now. I've done a little more fiddling and it's pretty good. I've also set the gain to around 19 dB. The only thing now is that the antenna needs improvement (as you said), bc there is a slight amount of noise due to a less than ideal signal.

Thank you so much for your help!

[AussieLand]

Hard to say from that if there is any distortion due to the style of music, as Joanne points out.

Try and upload a recording with something less harsh, or some speech or something.

Thanks Jim. Sound is sorted now!

[AussieLand]

i would like to see just a screenshot so I can clearly see the settings, make sure the ribbon bar, Home panel is visible.

Please make sure you don't have any audio EQ enabled, but I don't see clipping so doubt this is the case.

I see the signal is not super strong, what's it like with a strong signal?

Hi Simon,
First of all, I would like to congratulate you on all your hard work in producing such a fantastic program! Will be donating more funds next week.

The sound seems to be sorted now. I just need to improve on the antenna and then start listening to some other signals, as I'm sure the world is our oyster!

''Please make sure you don't have any audio EQ enabled'' Hmm, not sure where to find that setting.

Here is the screenshot in case something is a miss.

Cheers!

[Simon G4ELI]

Hi John,

Depending on the dongle 2.5 MHz is just too much. get a decent antenna and you'll see the RDS text. I also suggest zooming to the max to see more stations.

[AussieLand]

Hi John,

Depending on the dongle 2.5 MHz is just too much. get a decent antenna and you'll see the RDS text. I also suggest zooming to the max to see more stations.

Hi Simon,
I tried a lower frequency, but I found that I couldn't get the span in the spectrum section, it was cut on the ends. It seems happy at 2.5 Mhz.

Anyways, I've been playing with it and this is the configuration I've come up with.'

[Simon G4ELI]

Hi John,

Depending on the dongle 2.5 MHz is just too much. get a decent antenna and you'll see the RDS text. I also suggest zooming to the max to see more stations.

Hi Simon,
I tried a lower frequency, but I found that I couldn't get the span in the spectrum section, it was cut on the ends. It seems happy at 2.5 Mhz.

Anyways, I've been playing with it and this is the configuration I've come up with.'

Screenshot-2022-11-05-211333.jpeg

Looks better. Now switch on the RDS:

Ribbon Bar, Receive, Mode, Broadcast FM, Spectrum. If the signal's strong enough you'll see the data.