SDR-Bridge, CwSkimmer and the panadapter shake

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  • Updated 6 years ago
Using CwSkimmer with SDR-Bridge.  Occasionally CwSkimmer gets out of synch with the SSDR panadapter/slice.  Shaking/wiggling the pandapter display synchs them up again.

Is anyone else seeing this?

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com


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Al / NN4ZZ

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Posted 6 years ago

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Lee, Elmer

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Generally skimmer stays synced but not to the hz because of the way skimmer interfaces. Usually you will have to tune maybe 100 to 200 hz before skimmer will respond to a sync.
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Al / NN4ZZ

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Hi Lee,
Thanks, I noticed that also. It might be better if it synched at about 50 hz but not sure if its a problem.  

In addition I found 2 other conditions where shaking the panadapter is needed.

1 - If I view the SETTINGs in CwSkimmer, and then click OK, the frequency is changed on the skimmer display and skimmer waterfall until I shake the SSDR panadapter.  

2 - If I click tune a new signal on the SSDR panadapter, the skimmer display jumps to the right signal but the decoding does not start unless I shake the SSDR panadapter.

Have you seen either of these?

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com




(Edited)
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Lee, Elmer

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I told you...this is the nature of skimmer. I think ed is workng on trying to reduce the granularity of the step size, not sure where that stands. He does not have control over how skimmer is coded. I'm not sure but I think skimmer may have a bit of a AFC built in to peak the Sig in the passband so there may need to be a little slop to allow the AFC to peak.

73 w9oy
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Ed - W2RF

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Skimmer tuning  is currently limited to 100hz. The next Skimmer update will increase the tuning resolution to 10hz. When the new version of Skimmer is available I will post an updated SDR-Bridge.

I haven't been able to reproduce either of the other two items. Please post more details.

Thanks,

73 Ed W2RF
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Al / NN4ZZ

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Lee,
Thanks for confirming, I wasn't sure if you had the same experience on the 2 conditions above.  Will wait to see if Ed or others have any additional feedback.

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com

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Ed - W2RF

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Al,

It occurred to me that you may be running at  near 100% CPU utilization. That causes response to get a bit jumpy. Check in task mananger. CPU can be reduced a lot by lowering the display FPS to about 20 and the waterfall rate to about 75.

73 Ed W2RF
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Al / NN4ZZ

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Ed,
Here is the example of the click tune issue.

CPU is at about 60%  (slowing rate reduces CPU further but has no effect on issue)

See the video below, the decoding works sometimes but not on the click at 7.039 until I shake the panadapter about 7 seconds later.  

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com




Watch the click on 7.039 at 0:08 seconds and then at 0:15 the decoding begins



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Ed - W2RF

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Al,

The  click shown in the screenshot misses the frequency by a small amount. It  isn't much, but Skimmer only decodes when the frequency is very close.

A solution for this would be to go over to Skimmer and correct the click. Perhaps in the future the radio will auto-zero beat on the clicked station. I am not sure why shaking the panadapter helps.

73 Ed W2RF
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Al / NN4ZZ

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Ed,
Thanks, I noticed that clicking on the CwSkimmer waterfall works 100% of the time for me.  

I noticed that clicking on the panadapter is less accurate (or I'm just a little clumsy), depending on the zoom.  

I also thought it was odd that shaking the panadapter fixes it.   

Auto-zero beat would be a nice feature for SSDR.  I think it has been requested already.  In the mean time clicking on the CwSkimmer call or signal works fine.

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com



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Al / NN4ZZ

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Ed,
Here is an example of the CwSkimmer "settings view"  issue.

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com

Screenshot before looking at the settings on CwSkimmer - all is good





After looking at the settings, no changes, just click OK to close the settings.

Note: the frequency on the skimmer has changed, and the waterfall has moved. 

Shake the panadapter and it re-synchs




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Ed - W2RF

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Oh it's the Skimmer settings. Skimmer restarts when you press OK from settings (but not when you press CANCEL).  Skimmer does not announce that it has been suspended or when it restarts, so SDR-Bridge is unaware of these events. When it restarts, there is no synchronization. In this case the proper way to restore synchronization is to shake the panadapter, as you are doing. Or shake the Skimmer waterfall.

73 Ed W2RF

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Al / NN4ZZ

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Ed, Thanks, that explains it.   Cancel also works fine as you noted.  This is pretty minor anyway (how often do you need to go into settings anyway).   

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com

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K1UO - Larry

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Just as an aside..  I have been seeing  the same minor errors here.  I have learned to shake the panadapter for a quick fix of the sync.  Occasionally skimmer will come up and not start and I just unclick and restart from SDR-Bridge to get it going again.  It worked like a charm today to pick up a big 6M opening to CE and LU land.   NICE!