Possible Bulld 2645 NR4 Bug & Workaround

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RadioSDR1
Posts: 59
Joined: Sun Jun 26, 2022 4:41 pm

Possible Bulld 2645 NR4 Bug & Workaround

#1

Unread post by RadioSDR1 »

The new NR4 is great. However if one switches mode, say between LSB and SAM, undesired noise artifacts that sound like garbled water appear. Almost the same sound as not enough smoothing applied.

As a workaround to fix it, all one needs to do is just move the Reduction or the Smoothing or the Rescale slider (doesn’t matter which one) and either put it back exactly where it was or leave it after it was moved and the artifacts completely disappear. Interestingly, this is the only way that I have found as of yet to fix it except for shutting down and reopening SDR Console. If you merely stop and restart SDR Console, it will not fix it nor will turning off and on NR4.

To recreate the problem, open SDR Console (if already open then close and reopen). Tune to any frequency clear of any station or interference (not absolutely required but makes it easier to notice). Turn on NR4 if not already on with default settings. Toggle between AM and LSB. Observe how (after it settles down from the change after a couple seconds), the garbled waterfall sound appears. Then move any NR4 slider as little as 1db and then put it back. Problem goes away until you switch modes again. But you can switch between some modes and not have a problem.

For example, this does not seem to be a problem switching between USB and LSB or between SAM and AM but it is a problem switching between either Wide-U/Wide-L to either USB/LSB even if the filter bandwidth is exactly the same between the wide and narrow side band modes. Also the problem occurs switching between any FM mode.

To confirm my observations as I did this write up, I used an SDR Play RSP1A and was tuned to a frequency of 500kHz with a low IF sample bandwidth of 500kHz though I do not believe the bandwidth or frequency matters so far as I know. This behavior also seems to occur on the RTL-SDR Blog V3 so I do not think the problem is tied to hardware.

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