Gurgling audio

General discussion and support for the Peaberry SDR V2.

Gurgling audio

Postby jcaulkins » Wed Feb 18, 2015 2:42 am

Hi all,

I have been using my Peaberry V2 for some time now on a daily basis and make contacts daily. Lately I have noticed that the receive audio sounds ever so slightly gurgily. It sounds like a receiver on a unfiltered power supply. Only the Peaberry is experiencing this. Could this be a regulation issue? I'm not sure but I believe this happens after the Peaberry has been on for a long time, I have been leaving it on 24/7, I'm going to check this in the morning when it's cold. I'm using HDSDR. I can record this audio if anybody wants to hear it. Any ideas?

Joel
KB6QVI
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Re: Gurgling audio

Postby AE9RB » Wed Feb 18, 2015 3:32 am

I've had radios running for months at a time. It's not likely that. But there's several oscillators/PLLs in the design. It's possible one of them became unstable. If thermal changes or a quick reboot causes the problem to present differently, information about that could help narrow it down.
73 David AE9RB
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Re: Gurgling audio

Postby jcaulkins » Wed Feb 18, 2015 3:37 am

Hi David,

Thanks for the reply, rebooting doesn't seem to change anything but starting from a cold start I'm pretty sure the problem is not there. I'll know more in the morning when I can check it out. By the way, I really like the CW program, it's going to be nice, thanks.

Joel
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Re: Gurgling audio

Postby jcaulkins » Sun Feb 22, 2015 3:45 am

I have transferred my Peaberry over to my laptop due to a monitor failure on my main computer that I have been using for the PB. After 3-4 days I have not experience the gurgling audio problem again, so I must conclude that the problem was with the other computer. It was always short on resources anyway, now I'm using a laptop with a i5 proc and 6 gig of ram. Hope this helps anybody in the future that might experience this same problem.

Joel
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Re: Gurgling audio

Postby jcaulkins » Mon Feb 23, 2015 11:23 pm

Well,

I take back what I said in my previous post, the gurgling sound is back. Not only can you hear it, but you can see it in the audio waterfall.
http://www.youtube.com/watch?v=1xTQZhzOq8E

Joel
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Re: Gurgling audio

Postby W4MMP » Tue Feb 24, 2015 12:39 am

Hi Joel,
Yes, that really does appear to be a power supply issue. Have you scoped your power supply? Then check all three LDO voltage regulators.
73
Ron / W4MMP
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Re: Gurgling audio

Postby AE9RB » Tue Feb 24, 2015 1:36 am

There was a QRM tone in there that wasn't changing pitch so I'd guess your oscillators and PLLs are working fine. At least as far as I could tell with all the YouTube compression.

Are you sure it's not the AGC setting? Atmospheric conditions change so that at certain times it will resonate with the AGC speed you have selected.
73 David AE9RB
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Re: Gurgling audio

Postby jcaulkins » Fri Feb 27, 2015 8:04 pm

David,

Just a note to bring you up to date on the audio problem. I have tried running without AGC turned on and the problem still persists. I have checked all my PS's and they are within specs for AC ripple, I have even run from 12V gel cell and still have the audio problem. The curious thing is, I have made a IQ recording while its gurgling real bad and sent it to my Brother in Law who is also a member of this board, it was crystal clear when he played it on his computer under HDSDR. What is this saying? The problem seems to be localized to my QTH. Could something in my shop be mixing with the LO of the PB? I don't know, I'm grabbing at straws, any help would be appreciated.

Joel
KB6QVI
jcaulkins
 
Posts: 25
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Re: Gurgling audio

Postby AE9RB » Fri Feb 27, 2015 8:22 pm

An I/Q recording from HDSDR is an exact digital dump of what the Peaberry sends your computer. All the hardware mixing is already done at this point. If the I/Q recording is clean, the Peaberry hardware is not the problem. I think you need to be looking at things on your computer. Most of the interesting things happen on the computer. If a local signal is mixing in your audio it's being done in your computer.
73 David AE9RB
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