HDSDR Noise

General discussion and support for the Peaberry SDR V2.

HDSDR Noise

Postby pilotcfii » Tue Jan 07, 2014 5:42 pm

HDSDR.JPG
HDSDR picture with noise
HDSDR.JPG (246.37 KiB) Viewed 3150 times


Attached is a picture of HDSDR. It obviously does not look like the pictures in the build manual. The noise sounds like a harsh buzz. My first thought was power supply since I use a high efficiency Alinco DM330MV. It's a good supply and the ICOM it powers doesn't have a problem with noise. But to make sure I connected a gel cell battery. Noise is no different. From reading on here I suspect I still have a solder problem, either on the PSoC or PCM3060, so will continue that investigation. I would like suggestions of specific places to look instead of my just looking in general.

Looking at the pictures I notice the middle window (the one that looks like a band scope) looks like the build manual on page 16 but with the red vertical line and blue vertical line reversed. No idea what that could be.

Last I did try the Tx button in HDSDR and it seemed to work but the diagnostic LED did not flash. Perhaps that is related to the noise problem.

Update 1/7/2014 19:48Z - Reflowed some soldering on the PSoC & PMC3060 and now the Tx button does cause the diagnostic LED to flash. Still have the "buzz" though.
73
Dan Malcolm
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Re: HDSDR Noise

Postby KC5SB » Tue Jan 07, 2014 11:35 pm

Sounds very similar to my problem described in my post 'HDSDR Testing Question' of July 23, 2013. I described the sound as a 'buzzsaw' and my screen shots looked similar to yours. I don't remember the exact solution, but every problem I encountered was caused by soldering problems of one kind of another. This is probably not much help, but my suggestion is to very carefully check all solder joints with magnification and a good light.

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Re: HDSDR Noise

Postby pilotcfii » Wed Jan 08, 2014 12:24 am

Thanks Bill. That confirms my own suspicions. Every problem I've fixed so far has been a soldering problem.
73
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Re: HDSDR Noise

Postby n2dts » Wed Jan 08, 2014 1:30 am

Also make sure you do not have a shorted transformer.
I must have shorted my input transformer to the core ( I did not deburr the holes enough) and had various odd problems till I rewound it.
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Re: HDSDR Noise

Postby AE9RB » Wed Jan 08, 2014 6:42 pm

This is a bad connection between the PCM3060 and PSoC. Between this and the way you described the short in your USB problem leads me to believe you are not using enough flux or it is not of suitable quality.
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Re: HDSDR Noise

Postby pilotcfii » Wed Jan 08, 2014 7:25 pm

Reversed trace.JPG
JPG showing reversed traces
Reversed trace.JPG (31.76 KiB) Viewed 3108 times
Thanks David,

I was using a flux pen but I think you're right. I had to clear a couple solder bridges and tried the flux syringe I bought that dispenses a more past like flux. After the bridges were clear and I re-flowed the solder joints I now get just static in HDSDR. I also found that the flux paste works better when using solder wick. I have now cleared all known faults except the one in the attached picture. The vertical traces are reversed from what is shown in the build instructions.

Update @ 1431: I found that problem. It's the USB versus LSB selection in HDSDR. In the picture David has selected LSB, while I was using USB. :D
73
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Re: HDSDR Noise

Postby W4MMP » Tue Jan 14, 2014 7:14 pm

Hi,
I had the same exact problem with the buzz saw noise. While performing a complete review of the build, I found one side of R6 not on the pad. Actually I had not soldered one leg at all :shock: . Really stupid mistake, but I thought I would pass that along as the symptom it presented was exactly as the issue presented in this post.

73

Ron / W4MMP
73
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Re: HDSDR Noise

Postby pilotcfii » Tue Jan 14, 2014 8:26 pm

Thanks Ron. In my case I found several pins on the PCM3060 were not soldered. Took a really close look to see it but it's working now.
73
Dan Malcolm
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Re: HDSDR Noise

Postby W4MMP » Tue Jan 14, 2014 9:35 pm

Hi,
I have found the easiest and so far the best way to solder the SMD semiconductor chips is to use the method I believe David AE9RB has mentioned. That is not to try and keep the solder bridges from happening in the first place. Tack two pins first to hold the chip in place. Apply soldering flux to all pins and then apply the solder to each pin and NOT worry about bridges. Then use desoldering braid across one side of the chip and then the other. This removed all the bridges and cleaned up the soldering job quite nicely. I have not had an issue (knock on wood) so far with bad chip connections.

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