Sensitivity on one slice depends on which band oposite slice is on

  • 1
  • Problem
  • Updated 3 years ago
  • Solved
  • (Edited)
I am running SSDR v1.7.30 on a Flex 6300.

I just thought we were going through a bad period in the current sunspot cycle. No matter which band I chose, there were either no signals or very few, especially weak CW. This has been going on for at least a month. Then today, I had slice A tuned to 20M and B on 15 and decided to try tuning B to other bands and lo and behold, when I put B on 40M, both slices began acting normally, i.e. there was activity on both, (I'm guessing about 15-20 dB increase i signal strength)

I've also noticed a great change in waterfall sensitivity on one slice when changing bands with the opposite slice which may or not be related.

This problem didn't show up till I updated to v1.7.30

Documenting this would be a pain since I would have to do screenshots of every instance, but I will if needed.
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Robert AA6UP

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Posted 3 years ago

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K2CM

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Not sure if this is the same problem. When I put up two slices, only one slice has good sensitivity.....the slice that I operated on most recently. If I retune on the new slice, sensitivity is normal on the new slice. I believe this normal.
(Edited)
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Robert AA6UP

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I dunno, but I would think both slices should have normal sensitivity.
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George Molnar, KF2T, Elmer

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Is the internal ATU operating? Tuner memory may be a factor.
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W7NGA

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Official Response
Take note that the preamp gain doesn't change when changing slices if it is not desired. I suspect one slice sets the preamp gain to a new value and you are experiencing the result.
(Edited)
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Robert AA6UP

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Thanks for putting me on the right track Dan. Pp 91-95 in the SmartSDR User's Guide explains this in a little more detail but doesn't make clear why one slice/band should affect the other slice/band.  In any event, it was the preamp gain being affected and all I needed to do was to turn the preamp on and Presto - I'm back on 20 CW!

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